diff options
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/Makefile | 2 | ||||
| -rw-r--r-- | virt/kvm/Kconfig | 120 | ||||
| -rw-r--r-- | virt/kvm/Makefile.kvm | 15 | ||||
| -rw-r--r-- | virt/kvm/async_pf.c | 241 | ||||
| -rw-r--r-- | virt/kvm/async_pf.h | 24 | ||||
| -rw-r--r-- | virt/kvm/binary_stats.c | 144 | ||||
| -rw-r--r-- | virt/kvm/coalesced_mmio.c | 190 | ||||
| -rw-r--r-- | virt/kvm/coalesced_mmio.h | 39 | ||||
| -rw-r--r-- | virt/kvm/dirty_ring.c | 272 | ||||
| -rw-r--r-- | virt/kvm/eventfd.c | 1050 | ||||
| -rw-r--r-- | virt/kvm/guest_memfd.c | 1032 | ||||
| -rw-r--r-- | virt/kvm/irqchip.c | 261 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 6596 | ||||
| -rw-r--r-- | virt/kvm/kvm_mm.h | 100 | ||||
| -rw-r--r-- | virt/kvm/pfncache.c | 484 | ||||
| -rw-r--r-- | virt/kvm/vfio.c | 359 | ||||
| -rw-r--r-- | virt/kvm/vfio.h | 18 | ||||
| -rw-r--r-- | virt/lib/Kconfig | 3 | ||||
| -rw-r--r-- | virt/lib/Makefile | 2 | ||||
| -rw-r--r-- | virt/lib/irqbypass.c | 214 |
20 files changed, 11166 insertions, 0 deletions
diff --git a/virt/Makefile b/virt/Makefile new file mode 100644 index 000000000..1cfea9436 --- /dev/null +++ b/virt/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-y += lib/ diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig new file mode 100644 index 000000000..794976b88 --- /dev/null +++ b/virt/kvm/Kconfig @@ -0,0 +1,120 @@ +# SPDX-License-Identifier: GPL-2.0 +# KVM common configuration items and defaults + +config KVM_COMMON + bool + select EVENTFD + select INTERVAL_TREE + select MMU_NOTIFIER + select PREEMPT_NOTIFIERS + +config HAVE_KVM_PFNCACHE + bool + +config HAVE_KVM_IRQCHIP + bool + +config HAVE_KVM_IRQ_ROUTING + bool + +config HAVE_KVM_DIRTY_RING + bool + +# Only strongly ordered architectures can select this, as it doesn't +# put any explicit constraint on userspace ordering. They can also +# select the _ACQ_REL version. +config HAVE_KVM_DIRTY_RING_TSO + bool + select HAVE_KVM_DIRTY_RING + depends on X86 + +# Weakly ordered architectures can only select this, advertising +# to userspace the additional ordering requirements. +config HAVE_KVM_DIRTY_RING_ACQ_REL + bool + select HAVE_KVM_DIRTY_RING + +# Allow enabling both the dirty bitmap and dirty ring. Only architectures +# that need to dirty memory outside of a vCPU context should select this. +config NEED_KVM_DIRTY_RING_WITH_BITMAP + bool + depends on HAVE_KVM_DIRTY_RING + +config KVM_MMIO + bool + +config KVM_ASYNC_PF + bool + +# Toggle to switch between direct notification and batch job +config KVM_ASYNC_PF_SYNC + bool + +config HAVE_KVM_MSI + bool + +config HAVE_KVM_READONLY_MEM + bool + +config HAVE_KVM_CPU_RELAX_INTERCEPT + bool + +config KVM_VFIO + bool + +config HAVE_KVM_INVALID_WAKEUPS + bool + +config KVM_GENERIC_DIRTYLOG_READ_PROTECT + bool + +config KVM_GENERIC_PRE_FAULT_MEMORY + bool + +config KVM_COMPAT + def_bool y + depends on KVM && COMPAT && !(S390 || ARM64 || RISCV) + +config HAVE_KVM_IRQ_BYPASS + tristate + select IRQ_BYPASS_MANAGER + +config HAVE_KVM_VCPU_RUN_PID_CHANGE + bool + +config HAVE_KVM_NO_POLL + bool + +config VIRT_XFER_TO_GUEST_WORK + bool + +config HAVE_KVM_PM_NOTIFIER + bool + +config KVM_GENERIC_HARDWARE_ENABLING + bool + +config KVM_ELIDE_TLB_FLUSH_IF_YOUNG + bool + +config KVM_MMU_LOCKLESS_AGING + bool + +config KVM_GENERIC_MEMORY_ATTRIBUTES + bool + +config KVM_GUEST_MEMFD + select XARRAY_MULTI + bool + +config HAVE_KVM_ARCH_GMEM_PREPARE + bool + depends on KVM_GUEST_MEMFD + +config HAVE_KVM_ARCH_GMEM_INVALIDATE + bool + depends on KVM_GUEST_MEMFD + +config HAVE_KVM_ARCH_GMEM_POPULATE + bool + depends on KVM_GUEST_MEMFD diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm new file mode 100644 index 000000000..d047d4cf5 --- /dev/null +++ b/virt/kvm/Makefile.kvm @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for Kernel-based Virtual Machine module +# + +KVM ?= ../../../virt/kvm + +kvm-y := $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/binary_stats.o +kvm-$(CONFIG_KVM_VFIO) += $(KVM)/vfio.o +kvm-$(CONFIG_KVM_MMIO) += $(KVM)/coalesced_mmio.o +kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o +kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o +kvm-$(CONFIG_HAVE_KVM_DIRTY_RING) += $(KVM)/dirty_ring.o +kvm-$(CONFIG_HAVE_KVM_PFNCACHE) += $(KVM)/pfncache.o +kvm-$(CONFIG_KVM_GUEST_MEMFD) += $(KVM)/guest_memfd.o diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c new file mode 100644 index 000000000..b8aaa96b7 --- /dev/null +++ b/virt/kvm/async_pf.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kvm asynchronous fault support + * + * Copyright 2010 Red Hat, Inc. + * + * Author: + * Gleb Natapov <gleb@redhat.com> + */ + +#include <linux/kvm_host.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/mmu_context.h> +#include <linux/sched/mm.h> + +#include "async_pf.h" +#include <trace/events/kvm.h> + +static struct kmem_cache *async_pf_cache; + +int kvm_async_pf_init(void) +{ + async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); + + if (!async_pf_cache) + return -ENOMEM; + + return 0; +} + +void kvm_async_pf_deinit(void) +{ + kmem_cache_destroy(async_pf_cache); + async_pf_cache = NULL; +} + +void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) +{ + INIT_LIST_HEAD(&vcpu->async_pf.done); + INIT_LIST_HEAD(&vcpu->async_pf.queue); + spin_lock_init(&vcpu->async_pf.lock); +} + +static void async_pf_execute(struct work_struct *work) +{ + struct kvm_async_pf *apf = + container_of(work, struct kvm_async_pf, work); + struct kvm_vcpu *vcpu = apf->vcpu; + struct mm_struct *mm = vcpu->kvm->mm; + unsigned long addr = apf->addr; + gpa_t cr2_or_gpa = apf->cr2_or_gpa; + int locked = 1; + bool first; + + might_sleep(); + + /* + * Attempt to pin the VM's host address space, and simply skip gup() if + * acquiring a pin fail, i.e. if the process is exiting. Note, KVM + * holds a reference to its associated mm_struct until the very end of + * kvm_destroy_vm(), i.e. the struct itself won't be freed before this + * work item is fully processed. + */ + if (mmget_not_zero(mm)) { + mmap_read_lock(mm); + get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, &locked); + if (locked) + mmap_read_unlock(mm); + mmput(mm); + } + + /* + * Notify and kick the vCPU even if faulting in the page failed, e.g. + * so that the vCPU can retry the fault synchronously. + */ + if (IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC)) + kvm_arch_async_page_present(vcpu, apf); + + spin_lock(&vcpu->async_pf.lock); + first = list_empty(&vcpu->async_pf.done); + list_add_tail(&apf->link, &vcpu->async_pf.done); + spin_unlock(&vcpu->async_pf.lock); + + /* + * The apf struct may be freed by kvm_check_async_pf_completion() as + * soon as the lock is dropped. Nullify it to prevent improper usage. + */ + apf = NULL; + + if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first) + kvm_arch_async_page_present_queued(vcpu); + + trace_kvm_async_pf_completed(addr, cr2_or_gpa); + + __kvm_vcpu_wake_up(vcpu); +} + +static void kvm_flush_and_free_async_pf_work(struct kvm_async_pf *work) +{ + /* + * The async #PF is "done", but KVM must wait for the work item itself, + * i.e. async_pf_execute(), to run to completion. If KVM is a module, + * KVM must ensure *no* code owned by the KVM (the module) can be run + * after the last call to module_put(). Note, flushing the work item + * is always required when the item is taken off the completion queue. + * E.g. even if the vCPU handles the item in the "normal" path, the VM + * could be terminated before async_pf_execute() completes. + * + * Wake all events skip the queue and go straight done, i.e. don't + * need to be flushed (but sanity check that the work wasn't queued). + */ + if (work->wakeup_all) + WARN_ON_ONCE(work->work.func); + else + flush_work(&work->work); + kmem_cache_free(async_pf_cache, work); +} + +void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) +{ + /* cancel outstanding work queue item */ + while (!list_empty(&vcpu->async_pf.queue)) { + struct kvm_async_pf *work = + list_first_entry(&vcpu->async_pf.queue, + typeof(*work), queue); + list_del(&work->queue); + +#ifdef CONFIG_KVM_ASYNC_PF_SYNC + flush_work(&work->work); +#else + if (cancel_work_sync(&work->work)) + kmem_cache_free(async_pf_cache, work); +#endif + } + + spin_lock(&vcpu->async_pf.lock); + while (!list_empty(&vcpu->async_pf.done)) { + struct kvm_async_pf *work = + list_first_entry(&vcpu->async_pf.done, + typeof(*work), link); + list_del(&work->link); + + spin_unlock(&vcpu->async_pf.lock); + kvm_flush_and_free_async_pf_work(work); + spin_lock(&vcpu->async_pf.lock); + } + spin_unlock(&vcpu->async_pf.lock); + + vcpu->async_pf.queued = 0; +} + +void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) +{ + struct kvm_async_pf *work; + + while (!list_empty_careful(&vcpu->async_pf.done) && + kvm_arch_can_dequeue_async_page_present(vcpu)) { + spin_lock(&vcpu->async_pf.lock); + work = list_first_entry(&vcpu->async_pf.done, typeof(*work), + link); + list_del(&work->link); + spin_unlock(&vcpu->async_pf.lock); + + kvm_arch_async_page_ready(vcpu, work); + if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC)) + kvm_arch_async_page_present(vcpu, work); + + list_del(&work->queue); + vcpu->async_pf.queued--; + kvm_flush_and_free_async_pf_work(work); + } +} + +/* + * Try to schedule a job to handle page fault asynchronously. Returns 'true' on + * success, 'false' on failure (page fault has to be handled synchronously). + */ +bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, + unsigned long hva, struct kvm_arch_async_pf *arch) +{ + struct kvm_async_pf *work; + + if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) + return false; + + /* Arch specific code should not do async PF in this case */ + if (unlikely(kvm_is_error_hva(hva))) + return false; + + /* + * do alloc nowait since if we are going to sleep anyway we + * may as well sleep faulting in page + */ + work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); + if (!work) + return false; + + work->wakeup_all = false; + work->vcpu = vcpu; + work->cr2_or_gpa = cr2_or_gpa; + work->addr = hva; + work->arch = *arch; + + INIT_WORK(&work->work, async_pf_execute); + + list_add_tail(&work->queue, &vcpu->async_pf.queue); + vcpu->async_pf.queued++; + work->notpresent_injected = kvm_arch_async_page_not_present(vcpu, work); + + schedule_work(&work->work); + + return true; +} + +int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) +{ + struct kvm_async_pf *work; + bool first; + + if (!list_empty_careful(&vcpu->async_pf.done)) + return 0; + + work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); + if (!work) + return -ENOMEM; + + work->wakeup_all = true; + INIT_LIST_HEAD(&work->queue); /* for list_del to work */ + + spin_lock(&vcpu->async_pf.lock); + first = list_empty(&vcpu->async_pf.done); + list_add_tail(&work->link, &vcpu->async_pf.done); + spin_unlock(&vcpu->async_pf.lock); + + if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first) + kvm_arch_async_page_present_queued(vcpu); + + vcpu->async_pf.queued++; + return 0; +} diff --git a/virt/kvm/async_pf.h b/virt/kvm/async_pf.h new file mode 100644 index 000000000..90d1a7d8c --- /dev/null +++ b/virt/kvm/async_pf.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * kvm asynchronous fault support + * + * Copyright 2010 Red Hat, Inc. + * + * Author: + * Gleb Natapov <gleb@redhat.com> + */ + +#ifndef __KVM_ASYNC_PF_H__ +#define __KVM_ASYNC_PF_H__ + +#ifdef CONFIG_KVM_ASYNC_PF +int kvm_async_pf_init(void); +void kvm_async_pf_deinit(void); +void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu); +#else +#define kvm_async_pf_init() (0) +#define kvm_async_pf_deinit() do {} while (0) +#define kvm_async_pf_vcpu_init(C) do {} while (0) +#endif + +#endif diff --git a/virt/kvm/binary_stats.c b/virt/kvm/binary_stats.c new file mode 100644 index 000000000..76ce697c7 --- /dev/null +++ b/virt/kvm/binary_stats.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM binary statistics interface implementation + * + * Copyright 2021 Google LLC + */ + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/errno.h> +#include <linux/uaccess.h> + +/** + * kvm_stats_read() - Common function to read from the binary statistics + * file descriptor. + * + * @id: identification string of the stats + * @header: stats header for a vm or a vcpu + * @desc: start address of an array of stats descriptors for a vm or a vcpu + * @stats: start address of stats data block for a vm or a vcpu + * @size_stats: the size of stats data block pointed by @stats + * @user_buffer: start address of userspace buffer + * @size: requested read size from userspace + * @offset: the start position from which the content will be read for the + * corresponding vm or vcp file descriptor + * + * The file content of a vm/vcpu file descriptor is now defined as below: + * +-------------+ + * | Header | + * +-------------+ + * | id string | + * +-------------+ + * | Descriptors | + * +-------------+ + * | Stats Data | + * +-------------+ + * Although this function allows userspace to read any amount of data (as long + * as in the limit) from any position, the typical usage would follow below + * steps: + * 1. Read header from offset 0. Get the offset of descriptors and stats data + * and some other necessary information. This is a one-time work for the + * lifecycle of the corresponding vm/vcpu stats fd. + * 2. Read id string from its offset. This is a one-time work for the lifecycle + * of the corresponding vm/vcpu stats fd. + * 3. Read descriptors from its offset and discover all the stats by parsing + * descriptors. This is a one-time work for the lifecycle of the + * corresponding vm/vcpu stats fd. + * 4. Periodically read stats data from its offset using pread. + * + * Return: the number of bytes that has been successfully read + */ +ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header, + const struct kvm_stats_desc *desc, + void *stats, size_t size_stats, + char __user *user_buffer, size_t size, loff_t *offset) +{ + ssize_t len; + ssize_t copylen; + ssize_t remain = size; + size_t size_desc; + size_t size_header; + void *src; + loff_t pos = *offset; + char __user *dest = user_buffer; + + size_header = sizeof(*header); + size_desc = header->num_desc * sizeof(*desc); + + len = KVM_STATS_NAME_SIZE + size_header + size_desc + size_stats - pos; + len = min(len, remain); + if (len <= 0) + return 0; + remain = len; + + /* + * Copy kvm stats header. + * The header is the first block of content userspace usually read out. + * The pos is 0 and the copylen and remain would be the size of header. + * The copy of the header would be skipped if offset is larger than the + * size of header. That usually happens when userspace reads stats + * descriptors and stats data. + */ + copylen = size_header - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = (void *)header + pos; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* + * Copy kvm stats header id string. + * The id string is unique for every vm/vcpu, which is stored in kvm + * and kvm_vcpu structure. + * The id string is part of the stat header from the perspective of + * userspace, it is usually read out together with previous constant + * header part and could be skipped for later descriptors and stats + * data readings. + */ + copylen = header->id_offset + KVM_STATS_NAME_SIZE - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = id + pos - header->id_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* + * Copy kvm stats descriptors. + * The descriptors copy would be skipped in the typical case that + * userspace periodically read stats data, since the pos would be + * greater than the end address of descriptors + * (header->header.desc_offset + size_desc) causing copylen <= 0. + */ + copylen = header->desc_offset + size_desc - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = (void *)desc + pos - header->desc_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* Copy kvm stats values */ + copylen = header->data_offset + size_stats - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = stats + pos - header->data_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + pos += copylen; + } + + *offset = pos; + return len; +} diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c new file mode 100644 index 000000000..6b1d90161 --- /dev/null +++ b/virt/kvm/coalesced_mmio.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM coalesced MMIO + * + * Copyright (c) 2008 Bull S.A.S. + * Copyright 2009 Red Hat, Inc. and/or its affiliates. + * + * Author: Laurent Vivier <Laurent.Vivier@bull.net> + * + */ + +#include <kvm/iodev.h> + +#include <linux/kvm_host.h> +#include <linux/slab.h> +#include <linux/kvm.h> + +#include "coalesced_mmio.h" + +static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev) +{ + return container_of(dev, struct kvm_coalesced_mmio_dev, dev); +} + +static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev, + gpa_t addr, int len) +{ + /* is it in a batchable area ? + * (addr,len) is fully included in + * (zone->addr, zone->size) + */ + if (len < 0) + return 0; + if (addr + len < addr) + return 0; + if (addr < dev->zone.addr) + return 0; + if (addr + len > dev->zone.addr + dev->zone.size) + return 0; + return 1; +} + +static int coalesced_mmio_write(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, gpa_t addr, + int len, const void *val) +{ + struct kvm_coalesced_mmio_dev *dev = to_mmio(this); + struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring; + __u32 insert; + + if (!coalesced_mmio_in_range(dev, addr, len)) + return -EOPNOTSUPP; + + spin_lock(&dev->kvm->ring_lock); + + /* + * last is the index of the entry to fill. Verify userspace hasn't + * set last to be out of range, and that there is room in the ring. + * Leave one entry free in the ring so that userspace can differentiate + * between an empty ring and a full ring. + */ + insert = READ_ONCE(ring->last); + if (insert >= KVM_COALESCED_MMIO_MAX || + (insert + 1) % KVM_COALESCED_MMIO_MAX == READ_ONCE(ring->first)) { + spin_unlock(&dev->kvm->ring_lock); + return -EOPNOTSUPP; + } + + /* copy data in first free entry of the ring */ + + ring->coalesced_mmio[insert].phys_addr = addr; + ring->coalesced_mmio[insert].len = len; + memcpy(ring->coalesced_mmio[insert].data, val, len); + ring->coalesced_mmio[insert].pio = dev->zone.pio; + smp_wmb(); + ring->last = (insert + 1) % KVM_COALESCED_MMIO_MAX; + spin_unlock(&dev->kvm->ring_lock); + return 0; +} + +static void coalesced_mmio_destructor(struct kvm_io_device *this) +{ + struct kvm_coalesced_mmio_dev *dev = to_mmio(this); + + list_del(&dev->list); + + kfree(dev); +} + +static const struct kvm_io_device_ops coalesced_mmio_ops = { + .write = coalesced_mmio_write, + .destructor = coalesced_mmio_destructor, +}; + +int kvm_coalesced_mmio_init(struct kvm *kvm) +{ + struct page *page; + + page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + if (!page) + return -ENOMEM; + + kvm->coalesced_mmio_ring = page_address(page); + + /* + * We're using this spinlock to sync access to the coalesced ring. + * The list doesn't need its own lock since device registration and + * unregistration should only happen when kvm->slots_lock is held. + */ + spin_lock_init(&kvm->ring_lock); + INIT_LIST_HEAD(&kvm->coalesced_zones); + + return 0; +} + +void kvm_coalesced_mmio_free(struct kvm *kvm) +{ + if (kvm->coalesced_mmio_ring) + free_page((unsigned long)kvm->coalesced_mmio_ring); +} + +int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm, + struct kvm_coalesced_mmio_zone *zone) +{ + int ret; + struct kvm_coalesced_mmio_dev *dev; + + if (zone->pio != 1 && zone->pio != 0) + return -EINVAL; + + dev = kzalloc_obj(struct kvm_coalesced_mmio_dev, GFP_KERNEL_ACCOUNT); + if (!dev) + return -ENOMEM; + + kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops); + dev->kvm = kvm; + dev->zone = *zone; + + mutex_lock(&kvm->slots_lock); + ret = kvm_io_bus_register_dev(kvm, + zone->pio ? KVM_PIO_BUS : KVM_MMIO_BUS, + zone->addr, zone->size, &dev->dev); + if (ret < 0) + goto out_free_dev; + list_add_tail(&dev->list, &kvm->coalesced_zones); + mutex_unlock(&kvm->slots_lock); + + return 0; + +out_free_dev: + mutex_unlock(&kvm->slots_lock); + kfree(dev); + + return ret; +} + +int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm, + struct kvm_coalesced_mmio_zone *zone) +{ + struct kvm_coalesced_mmio_dev *dev, *tmp; + int r; + + if (zone->pio != 1 && zone->pio != 0) + return -EINVAL; + + mutex_lock(&kvm->slots_lock); + + list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list) { + if (zone->pio == dev->zone.pio && + coalesced_mmio_in_range(dev, zone->addr, zone->size)) { + r = kvm_io_bus_unregister_dev(kvm, + zone->pio ? KVM_PIO_BUS : KVM_MMIO_BUS, &dev->dev); + /* + * On failure, unregister destroys all devices on the + * bus, including the target device. There's no need + * to restart the walk as there aren't any zones left. + */ + if (r) + break; + } + } + + mutex_unlock(&kvm->slots_lock); + + /* + * Ignore the result of kvm_io_bus_unregister_dev(), from userspace's + * perspective, the coalesced MMIO is most definitely unregistered. + */ + return 0; +} diff --git a/virt/kvm/coalesced_mmio.h b/virt/kvm/coalesced_mmio.h new file mode 100644 index 000000000..36f84264e --- /dev/null +++ b/virt/kvm/coalesced_mmio.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __KVM_COALESCED_MMIO_H__ +#define __KVM_COALESCED_MMIO_H__ + +/* + * KVM coalesced MMIO + * + * Copyright (c) 2008 Bull S.A.S. + * + * Author: Laurent Vivier <Laurent.Vivier@bull.net> + * + */ + +#ifdef CONFIG_KVM_MMIO + +#include <linux/list.h> + +struct kvm_coalesced_mmio_dev { + struct list_head list; + struct kvm_io_device dev; + struct kvm *kvm; + struct kvm_coalesced_mmio_zone zone; +}; + +int kvm_coalesced_mmio_init(struct kvm *kvm); +void kvm_coalesced_mmio_free(struct kvm *kvm); +int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm, + struct kvm_coalesced_mmio_zone *zone); +int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm, + struct kvm_coalesced_mmio_zone *zone); + +#else + +static inline int kvm_coalesced_mmio_init(struct kvm *kvm) { return 0; } +static inline void kvm_coalesced_mmio_free(struct kvm *kvm) { } + +#endif + +#endif diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c new file mode 100644 index 000000000..572b854ed --- /dev/null +++ b/virt/kvm/dirty_ring.c @@ -0,0 +1,272 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM dirty ring implementation + * + * Copyright 2019 Red Hat, Inc. + */ +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/vmalloc.h> +#include <linux/kvm_dirty_ring.h> +#include <trace/events/kvm.h> +#include "kvm_mm.h" + +int __weak kvm_cpu_dirty_log_size(struct kvm *kvm) +{ + return 0; +} + +u32 kvm_dirty_ring_get_rsvd_entries(struct kvm *kvm) +{ + return KVM_DIRTY_RING_RSVD_ENTRIES + kvm_cpu_dirty_log_size(kvm); +} + +bool kvm_use_dirty_bitmap(struct kvm *kvm) +{ + lockdep_assert_held(&kvm->slots_lock); + + return !kvm->dirty_ring_size || kvm->dirty_ring_with_bitmap; +} + +#ifndef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP +bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm) +{ + return false; +} +#endif + +static u32 kvm_dirty_ring_used(struct kvm_dirty_ring *ring) +{ + return READ_ONCE(ring->dirty_index) - READ_ONCE(ring->reset_index); +} + +static bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring) +{ + return kvm_dirty_ring_used(ring) >= ring->soft_limit; +} + +static bool kvm_dirty_ring_full(struct kvm_dirty_ring *ring) +{ + return kvm_dirty_ring_used(ring) >= ring->size; +} + +static void kvm_reset_dirty_gfn(struct kvm *kvm, u32 slot, u64 offset, u64 mask) +{ + struct kvm_memory_slot *memslot; + int as_id, id; + + as_id = slot >> 16; + id = (u16)slot; + + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) + return; + + memslot = id_to_memslot(__kvm_memslots(kvm, as_id), id); + + if (!memslot || offset >= memslot->npages || + offset + __fls(mask) >= memslot->npages) + return; + + KVM_MMU_LOCK(kvm); + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, offset, mask); + KVM_MMU_UNLOCK(kvm); +} + +int kvm_dirty_ring_alloc(struct kvm *kvm, struct kvm_dirty_ring *ring, + int index, u32 size) +{ + ring->dirty_gfns = vzalloc(size); + if (!ring->dirty_gfns) + return -ENOMEM; + + ring->size = size / sizeof(struct kvm_dirty_gfn); + ring->soft_limit = ring->size - kvm_dirty_ring_get_rsvd_entries(kvm); + ring->dirty_index = 0; + ring->reset_index = 0; + ring->index = index; + + return 0; +} + +static inline void kvm_dirty_gfn_set_invalid(struct kvm_dirty_gfn *gfn) +{ + smp_store_release(&gfn->flags, 0); +} + +static inline void kvm_dirty_gfn_set_dirtied(struct kvm_dirty_gfn *gfn) +{ + gfn->flags = KVM_DIRTY_GFN_F_DIRTY; +} + +static inline bool kvm_dirty_gfn_harvested(struct kvm_dirty_gfn *gfn) +{ + return smp_load_acquire(&gfn->flags) & KVM_DIRTY_GFN_F_RESET; +} + +int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring, + int *nr_entries_reset) +{ + /* + * To minimize mmu_lock contention, batch resets for harvested entries + * whose gfns are in the same slot, and are within N frame numbers of + * each other, where N is the number of bits in an unsigned long. For + * simplicity, process the current set of entries when the next entry + * can't be included in the batch. + * + * Track the current batch slot, the gfn offset into the slot for the + * batch, and the bitmask of gfns that need to be reset (relative to + * offset). Note, the offset may be adjusted backwards, e.g. so that + * a sequence of gfns X, X-1, ... X-N-1 can be batched. + */ + u32 cur_slot, next_slot; + u64 cur_offset, next_offset; + unsigned long mask = 0; + struct kvm_dirty_gfn *entry; + + /* + * Ensure concurrent calls to KVM_RESET_DIRTY_RINGS are serialized, + * e.g. so that KVM fully resets all entries processed by a given call + * before returning to userspace. Holding slots_lock also protects + * the various memslot accesses. + */ + lockdep_assert_held(&kvm->slots_lock); + + while (likely((*nr_entries_reset) < INT_MAX)) { + if (signal_pending(current)) + return -EINTR; + + entry = &ring->dirty_gfns[ring->reset_index & (ring->size - 1)]; + + if (!kvm_dirty_gfn_harvested(entry)) + break; + + next_slot = READ_ONCE(entry->slot); + next_offset = READ_ONCE(entry->offset); + + /* Update the flags to reflect that this GFN is reset */ + kvm_dirty_gfn_set_invalid(entry); + + ring->reset_index++; + (*nr_entries_reset)++; + + if (mask) { + /* + * While the size of each ring is fixed, it's possible + * for the ring to be constantly re-dirtied/harvested + * while the reset is in-progress (the hard limit exists + * only to guard against the count becoming negative). + */ + cond_resched(); + + /* + * Try to coalesce the reset operations when the guest + * is scanning pages in the same slot. + */ + if (next_slot == cur_slot) { + s64 delta = next_offset - cur_offset; + + if (delta >= 0 && delta < BITS_PER_LONG) { + mask |= 1ull << delta; + continue; + } + + /* Backwards visit, careful about overflows! */ + if (delta > -BITS_PER_LONG && delta < 0 && + (mask << -delta >> -delta) == mask) { + cur_offset = next_offset; + mask = (mask << -delta) | 1; + continue; + } + } + + /* + * Reset the slot for all the harvested entries that + * have been gathered, but not yet fully processed. + */ + kvm_reset_dirty_gfn(kvm, cur_slot, cur_offset, mask); + } + + /* + * The current slot was reset or this is the first harvested + * entry, (re)initialize the metadata. + */ + cur_slot = next_slot; + cur_offset = next_offset; + mask = 1; + } + + /* + * Perform a final reset if there are harvested entries that haven't + * been processed, which is guaranteed if at least one harvested was + * found. The loop only performs a reset when the "next" entry can't + * be batched with the "current" entry(s), and that reset processes the + * _current_ entry(s); i.e. the last harvested entry, a.k.a. next, will + * always be left pending. + */ + if (mask) + kvm_reset_dirty_gfn(kvm, cur_slot, cur_offset, mask); + + /* + * The request KVM_REQ_DIRTY_RING_SOFT_FULL will be cleared + * by the VCPU thread next time when it enters the guest. + */ + + trace_kvm_dirty_ring_reset(ring); + + return 0; +} + +void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset) +{ + struct kvm_dirty_ring *ring = &vcpu->dirty_ring; + struct kvm_dirty_gfn *entry; + + /* It should never get full */ + WARN_ON_ONCE(kvm_dirty_ring_full(ring)); + + entry = &ring->dirty_gfns[ring->dirty_index & (ring->size - 1)]; + + entry->slot = slot; + entry->offset = offset; + /* + * Make sure the data is filled in before we publish this to + * the userspace program. There's no paired kernel-side reader. + */ + smp_wmb(); + kvm_dirty_gfn_set_dirtied(entry); + ring->dirty_index++; + trace_kvm_dirty_ring_push(ring, slot, offset); + + if (kvm_dirty_ring_soft_full(ring)) + kvm_make_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu); +} + +bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu) +{ + /* + * The VCPU isn't runnable when the dirty ring becomes soft full. + * The KVM_REQ_DIRTY_RING_SOFT_FULL event is always set to prevent + * the VCPU from running until the dirty pages are harvested and + * the dirty ring is reset by userspace. + */ + if (kvm_check_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu) && + kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) { + kvm_make_request(KVM_REQ_DIRTY_RING_SOFT_FULL, vcpu); + vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; + trace_kvm_dirty_ring_exit(vcpu); + return true; + } + + return false; +} + +struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset) +{ + return vmalloc_to_page((void *)ring->dirty_gfns + offset * PAGE_SIZE); +} + +void kvm_dirty_ring_free(struct kvm_dirty_ring *ring) +{ + vfree(ring->dirty_gfns); + ring->dirty_gfns = NULL; +} diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c new file mode 100644 index 000000000..93ad2ebc9 --- /dev/null +++ b/virt/kvm/eventfd.c @@ -0,0 +1,1050 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kvm eventfd support - use eventfd objects to signal various KVM events + * + * Copyright 2009 Novell. All Rights Reserved. + * Copyright 2010 Red Hat, Inc. and/or its affiliates. + * + * Author: + * Gregory Haskins <ghaskins@novell.com> + */ + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/kvm_irqfd.h> +#include <linux/workqueue.h> +#include <linux/syscalls.h> +#include <linux/wait.h> +#include <linux/poll.h> +#include <linux/file.h> +#include <linux/list.h> +#include <linux/eventfd.h> +#include <linux/kernel.h> +#include <linux/srcu.h> +#include <linux/slab.h> +#include <linux/seqlock.h> +#include <linux/irqbypass.h> +#include <linux/unaligned.h> +#include <trace/events/kvm.h> + +#include <kvm/iodev.h> + +#ifdef CONFIG_HAVE_KVM_IRQCHIP + +static struct workqueue_struct *irqfd_cleanup_wq; + +bool __attribute__((weak)) +kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args) +{ + return true; +} + +static void +irqfd_inject(struct work_struct *work) +{ + struct kvm_kernel_irqfd *irqfd = + container_of(work, struct kvm_kernel_irqfd, inject); + struct kvm *kvm = irqfd->kvm; + + if (!irqfd->resampler) { + kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1, + false); + kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0, + false); + } else + kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, + irqfd->gsi, 1, false); +} + +static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler) +{ + struct kvm_kernel_irqfd *irqfd; + + list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link, + srcu_read_lock_held(&resampler->kvm->irq_srcu)) + eventfd_signal(irqfd->resamplefd); +} + +/* + * Since resampler irqfds share an IRQ source ID, we de-assert once + * then notify all of the resampler irqfds using this GSI. We can't + * do multiple de-asserts or we risk racing with incoming re-asserts. + */ +static void +irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) +{ + struct kvm_kernel_irqfd_resampler *resampler; + struct kvm *kvm; + int idx; + + resampler = container_of(kian, + struct kvm_kernel_irqfd_resampler, notifier); + kvm = resampler->kvm; + + kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, + resampler->notifier.gsi, 0, false); + + idx = srcu_read_lock(&kvm->irq_srcu); + irqfd_resampler_notify(resampler); + srcu_read_unlock(&kvm->irq_srcu, idx); +} + +static void +irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd) +{ + struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler; + struct kvm *kvm = resampler->kvm; + + mutex_lock(&kvm->irqfds.resampler_lock); + + list_del_rcu(&irqfd->resampler_link); + + if (list_empty(&resampler->list)) { + list_del_rcu(&resampler->link); + kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier); + /* + * synchronize_srcu_expedited(&kvm->irq_srcu) already called + * in kvm_unregister_irq_ack_notifier(). + */ + kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, + resampler->notifier.gsi, 0, false); + kfree(resampler); + } else { + synchronize_srcu_expedited(&kvm->irq_srcu); + } + + mutex_unlock(&kvm->irqfds.resampler_lock); +} + +/* + * Race-free decouple logic (ordering is critical) + */ +static void +irqfd_shutdown(struct work_struct *work) +{ + struct kvm_kernel_irqfd *irqfd = + container_of(work, struct kvm_kernel_irqfd, shutdown); + struct kvm *kvm = irqfd->kvm; + u64 cnt; + + /* Make sure irqfd has been initialized in assign path. */ + synchronize_srcu_expedited(&kvm->irq_srcu); + + /* + * Synchronize with the wait-queue and unhook ourselves to prevent + * further events. + */ + eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt); + + /* + * We know no new events will be scheduled at this point, so block + * until all previously outstanding events have completed + */ + flush_work(&irqfd->inject); + + if (irqfd->resampler) { + irqfd_resampler_shutdown(irqfd); + eventfd_ctx_put(irqfd->resamplefd); + } + + /* + * It is now safe to release the object's resources + */ +#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) + irq_bypass_unregister_consumer(&irqfd->consumer); +#endif + eventfd_ctx_put(irqfd->eventfd); + kfree(irqfd); +} + + +static bool irqfd_is_active(struct kvm_kernel_irqfd *irqfd) +{ + /* + * Assert that either irqfds.lock or SRCU is held, as irqfds.lock must + * be held to prevent false positives (on the irqfd being active), and + * while false negatives are impossible as irqfds are never added back + * to the list once they're deactivated, the caller must at least hold + * SRCU to guard against routing changes if the irqfd is deactivated. + */ + lockdep_assert_once(lockdep_is_held(&irqfd->kvm->irqfds.lock) || + srcu_read_lock_held(&irqfd->kvm->irq_srcu)); + + return list_empty(&irqfd->list) ? false : true; +} + +/* + * Mark the irqfd as inactive and schedule it for removal + */ +static void irqfd_deactivate(struct kvm_kernel_irqfd *irqfd) +{ + lockdep_assert_held(&irqfd->kvm->irqfds.lock); + + BUG_ON(!irqfd_is_active(irqfd)); + + list_del_init(&irqfd->list); + + queue_work(irqfd_cleanup_wq, &irqfd->shutdown); +} + +int __attribute__((weak)) kvm_arch_set_irq_inatomic( + struct kvm_kernel_irq_routing_entry *irq, + struct kvm *kvm, int irq_source_id, + int level, + bool line_status) +{ + return -EWOULDBLOCK; +} + +/* + * Called with wqh->lock held and interrupts disabled + */ +static int +irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) +{ + struct kvm_kernel_irqfd *irqfd = + container_of(wait, struct kvm_kernel_irqfd, wait); + __poll_t flags = key_to_poll(key); + struct kvm_kernel_irq_routing_entry irq; + struct kvm *kvm = irqfd->kvm; + unsigned seq; + int idx; + int ret = 0; + + if (flags & EPOLLIN) { + /* + * WARNING: Do NOT take irqfds.lock in any path except EPOLLHUP, + * as KVM holds irqfds.lock when registering the irqfd with the + * eventfd. + */ + u64 cnt; + eventfd_ctx_do_read(irqfd->eventfd, &cnt); + + idx = srcu_read_lock(&kvm->irq_srcu); + do { + seq = read_seqcount_begin(&irqfd->irq_entry_sc); + irq = irqfd->irq_entry; + } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq)); + + /* + * An event has been signaled, inject an interrupt unless the + * irqfd is being deassigned (isn't active), in which case the + * routing information may be stale (once the irqfd is removed + * from the list, it will stop receiving routing updates). + */ + if (unlikely(!irqfd_is_active(irqfd)) || + kvm_arch_set_irq_inatomic(&irq, kvm, + KVM_USERSPACE_IRQ_SOURCE_ID, 1, + false) == -EWOULDBLOCK) + schedule_work(&irqfd->inject); + srcu_read_unlock(&kvm->irq_srcu, idx); + ret = 1; + } + + if (flags & EPOLLHUP) { + /* The eventfd is closing, detach from KVM */ + unsigned long iflags; + + /* + * Taking irqfds.lock is safe here, as KVM holds a reference to + * the eventfd when registering the irqfd, i.e. this path can't + * be reached while kvm_irqfd_add() is running. + */ + spin_lock_irqsave(&kvm->irqfds.lock, iflags); + + /* + * We must check if someone deactivated the irqfd before + * we could acquire the irqfds.lock since the item is + * deactivated from the KVM side before it is unhooked from + * the wait-queue. If it is already deactivated, we can + * simply return knowing the other side will cleanup for us. + * We cannot race against the irqfd going away since the + * other side is required to acquire wqh->lock, which we hold + */ + if (irqfd_is_active(irqfd)) + irqfd_deactivate(irqfd); + + spin_unlock_irqrestore(&kvm->irqfds.lock, iflags); + } + + return ret; +} + +static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd) +{ + struct kvm_kernel_irq_routing_entry *e; + struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; + int n_entries; + + lockdep_assert_held(&kvm->irqfds.lock); + + n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); + + write_seqcount_begin(&irqfd->irq_entry_sc); + + e = entries; + if (n_entries == 1) + irqfd->irq_entry = *e; + else + irqfd->irq_entry.type = 0; + + write_seqcount_end(&irqfd->irq_entry_sc); +} + +struct kvm_irqfd_pt { + struct kvm_kernel_irqfd *irqfd; + struct kvm *kvm; + poll_table pt; + int ret; +}; + +static void kvm_irqfd_register(struct file *file, wait_queue_head_t *wqh, + poll_table *pt) +{ + struct kvm_irqfd_pt *p = container_of(pt, struct kvm_irqfd_pt, pt); + struct kvm_kernel_irqfd *irqfd = p->irqfd; + struct kvm *kvm = p->kvm; + + /* + * Note, irqfds.lock protects the irqfd's irq_entry, i.e. its routing, + * and irqfds.items. It does NOT protect registering with the eventfd. + */ + spin_lock_irq(&kvm->irqfds.lock); + + /* + * Initialize the routing information prior to adding the irqfd to the + * eventfd's waitqueue, as irqfd_wakeup() can be invoked as soon as the + * irqfd is registered. + */ + irqfd_update(kvm, irqfd); + + /* + * Add the irqfd as a priority waiter on the eventfd, with a custom + * wake-up handler, so that KVM *and only KVM* is notified whenever the + * underlying eventfd is signaled. + */ + init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); + + /* + * Temporarily lie to lockdep about holding irqfds.lock to avoid a + * false positive regarding potential deadlock with irqfd_wakeup() + * (see irqfd_wakeup() for details). + * + * Adding to the wait queue will fail if there is already a priority + * waiter, i.e. if the eventfd is associated with another irqfd (in any + * VM). Note, kvm_irqfd_deassign() waits for all in-flight shutdown + * jobs to complete, i.e. ensures the irqfd has been removed from the + * eventfd's waitqueue before returning to userspace. + */ + spin_release(&kvm->irqfds.lock.dep_map, _RET_IP_); + p->ret = add_wait_queue_priority_exclusive(wqh, &irqfd->wait); + spin_acquire(&kvm->irqfds.lock.dep_map, 0, 0, _RET_IP_); + if (p->ret) + goto out; + + list_add_tail(&irqfd->list, &kvm->irqfds.items); + +out: + spin_unlock_irq(&kvm->irqfds.lock); +} + +#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) +void __attribute__((weak)) kvm_arch_irq_bypass_stop( + struct irq_bypass_consumer *cons) +{ +} + +void __attribute__((weak)) kvm_arch_irq_bypass_start( + struct irq_bypass_consumer *cons) +{ +} + +void __weak kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd, + struct kvm_kernel_irq_routing_entry *old, + struct kvm_kernel_irq_routing_entry *new) +{ + +} +#endif + +static int +kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) +{ + struct kvm_kernel_irqfd *irqfd; + struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; + struct kvm_irqfd_pt irqfd_pt; + int ret; + __poll_t events; + int idx; + + if (!kvm_arch_intc_initialized(kvm)) + return -EAGAIN; + + if (!kvm_arch_irqfd_allowed(kvm, args)) + return -EINVAL; + + irqfd = kzalloc_obj(*irqfd, GFP_KERNEL_ACCOUNT); + if (!irqfd) + return -ENOMEM; + + irqfd->kvm = kvm; + irqfd->gsi = args->gsi; + INIT_LIST_HEAD(&irqfd->list); + INIT_WORK(&irqfd->inject, irqfd_inject); + INIT_WORK(&irqfd->shutdown, irqfd_shutdown); + seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock); + + CLASS(fd, f)(args->fd); + if (fd_empty(f)) { + ret = -EBADF; + goto out; + } + + eventfd = eventfd_ctx_fileget(fd_file(f)); + if (IS_ERR(eventfd)) { + ret = PTR_ERR(eventfd); + goto out; + } + + irqfd->eventfd = eventfd; + + if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) { + struct kvm_kernel_irqfd_resampler *resampler; + + resamplefd = eventfd_ctx_fdget(args->resamplefd); + if (IS_ERR(resamplefd)) { + ret = PTR_ERR(resamplefd); + goto fail; + } + + irqfd->resamplefd = resamplefd; + INIT_LIST_HEAD(&irqfd->resampler_link); + + mutex_lock(&kvm->irqfds.resampler_lock); + + list_for_each_entry(resampler, + &kvm->irqfds.resampler_list, link) { + if (resampler->notifier.gsi == irqfd->gsi) { + irqfd->resampler = resampler; + break; + } + } + + if (!irqfd->resampler) { + resampler = kzalloc_obj(*resampler, GFP_KERNEL_ACCOUNT); + if (!resampler) { + ret = -ENOMEM; + mutex_unlock(&kvm->irqfds.resampler_lock); + goto fail; + } + + resampler->kvm = kvm; + INIT_LIST_HEAD(&resampler->list); + resampler->notifier.gsi = irqfd->gsi; + resampler->notifier.irq_acked = irqfd_resampler_ack; + INIT_LIST_HEAD(&resampler->link); + + list_add_rcu(&resampler->link, &kvm->irqfds.resampler_list); + kvm_register_irq_ack_notifier(kvm, + &resampler->notifier); + irqfd->resampler = resampler; + } + + list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); + synchronize_srcu_expedited(&kvm->irq_srcu); + + mutex_unlock(&kvm->irqfds.resampler_lock); + } + + /* + * Set the irqfd routing and add it to KVM's list before registering + * the irqfd with the eventfd, so that the routing information is valid + * and stays valid, e.g. if there are GSI routing changes, prior to + * making the irqfd visible, i.e. before it might be signaled. + * + * Note, holding SRCU ensures a stable read of routing information, and + * also prevents irqfd_shutdown() from freeing the irqfd before it's + * fully initialized. + */ + idx = srcu_read_lock(&kvm->irq_srcu); + + /* + * Register the irqfd with the eventfd by polling on the eventfd, and + * simultaneously and the irqfd to KVM's list. If there was en event + * pending on the eventfd prior to registering, manually trigger IRQ + * injection. + */ + irqfd_pt.irqfd = irqfd; + irqfd_pt.kvm = kvm; + init_poll_funcptr(&irqfd_pt.pt, kvm_irqfd_register); + + events = vfs_poll(fd_file(f), &irqfd_pt.pt); + + ret = irqfd_pt.ret; + if (ret) + goto fail_poll; + + if (events & EPOLLIN) + schedule_work(&irqfd->inject); + +#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) + if (kvm_arch_has_irq_bypass()) { + irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer; + irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer; + irqfd->consumer.stop = kvm_arch_irq_bypass_stop; + irqfd->consumer.start = kvm_arch_irq_bypass_start; + ret = irq_bypass_register_consumer(&irqfd->consumer, irqfd->eventfd); + if (ret) + pr_info("irq bypass consumer (eventfd %p) registration fails: %d\n", + irqfd->eventfd, ret); + } +#endif + + srcu_read_unlock(&kvm->irq_srcu, idx); + return 0; + +fail_poll: + srcu_read_unlock(&kvm->irq_srcu, idx); +fail: + if (irqfd->resampler) + irqfd_resampler_shutdown(irqfd); + + if (resamplefd && !IS_ERR(resamplefd)) + eventfd_ctx_put(resamplefd); + + if (eventfd && !IS_ERR(eventfd)) + eventfd_ctx_put(eventfd); + +out: + kfree(irqfd); + return ret; +} + +bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) +{ + struct kvm_irq_ack_notifier *kian; + int gsi, idx; + + idx = srcu_read_lock(&kvm->irq_srcu); + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); + if (gsi != -1) + hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list, + link, srcu_read_lock_held(&kvm->irq_srcu)) + if (kian->gsi == gsi) { + srcu_read_unlock(&kvm->irq_srcu, idx); + return true; + } + + srcu_read_unlock(&kvm->irq_srcu, idx); + + return false; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_irq_has_notifier); + +void kvm_notify_acked_gsi(struct kvm *kvm, int gsi) +{ + struct kvm_irq_ack_notifier *kian; + + hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list, + link, srcu_read_lock_held(&kvm->irq_srcu)) + if (kian->gsi == gsi) + kian->irq_acked(kian); +} + +void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) +{ + int gsi, idx; + + trace_kvm_ack_irq(irqchip, pin); + + idx = srcu_read_lock(&kvm->irq_srcu); + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); + if (gsi != -1) + kvm_notify_acked_gsi(kvm, gsi); + srcu_read_unlock(&kvm->irq_srcu, idx); +} + +void kvm_register_irq_ack_notifier(struct kvm *kvm, + struct kvm_irq_ack_notifier *kian) +{ + mutex_lock(&kvm->irq_lock); + hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); + mutex_unlock(&kvm->irq_lock); + kvm_arch_post_irq_ack_notifier_list_update(kvm); +} + +void kvm_unregister_irq_ack_notifier(struct kvm *kvm, + struct kvm_irq_ack_notifier *kian) +{ + mutex_lock(&kvm->irq_lock); + hlist_del_init_rcu(&kian->link); + mutex_unlock(&kvm->irq_lock); + synchronize_srcu_expedited(&kvm->irq_srcu); + kvm_arch_post_irq_ack_notifier_list_update(kvm); +} + +/* + * shutdown any irqfd's that match fd+gsi + */ +static int +kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) +{ + struct kvm_kernel_irqfd *irqfd, *tmp; + struct eventfd_ctx *eventfd; + + eventfd = eventfd_ctx_fdget(args->fd); + if (IS_ERR(eventfd)) + return PTR_ERR(eventfd); + + spin_lock_irq(&kvm->irqfds.lock); + + list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { + if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) + irqfd_deactivate(irqfd); + } + + spin_unlock_irq(&kvm->irqfds.lock); + eventfd_ctx_put(eventfd); + + /* + * Block until we know all outstanding shutdown jobs have completed + * so that we guarantee there will not be any more interrupts on this + * gsi once this deassign function returns. + */ + flush_workqueue(irqfd_cleanup_wq); + + return 0; +} + +int +kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) +{ + if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE)) + return -EINVAL; + + if (args->flags & KVM_IRQFD_FLAG_DEASSIGN) + return kvm_irqfd_deassign(kvm, args); + + return kvm_irqfd_assign(kvm, args); +} + +/* + * This function is called as the kvm VM fd is being released. Shutdown all + * irqfds that still remain open + */ +void +kvm_irqfd_release(struct kvm *kvm) +{ + struct kvm_kernel_irqfd *irqfd, *tmp; + + spin_lock_irq(&kvm->irqfds.lock); + + list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) + irqfd_deactivate(irqfd); + + spin_unlock_irq(&kvm->irqfds.lock); + + /* + * Block until we know all outstanding shutdown jobs have completed + * since we do not take a kvm* reference. + */ + flush_workqueue(irqfd_cleanup_wq); + +} + +/* + * Take note of a change in irq routing. + * Caller must invoke synchronize_srcu_expedited(&kvm->irq_srcu) afterwards. + */ +void kvm_irq_routing_update(struct kvm *kvm) +{ + struct kvm_kernel_irqfd *irqfd; + + spin_lock_irq(&kvm->irqfds.lock); + + list_for_each_entry(irqfd, &kvm->irqfds.items, list) { +#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) + /* Under irqfds.lock, so can read irq_entry safely */ + struct kvm_kernel_irq_routing_entry old = irqfd->irq_entry; +#endif + + irqfd_update(kvm, irqfd); + +#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) + if (irqfd->producer) + kvm_arch_update_irqfd_routing(irqfd, &old, &irqfd->irq_entry); +#endif + } + + spin_unlock_irq(&kvm->irqfds.lock); +} + +bool kvm_notify_irqfd_resampler(struct kvm *kvm, + unsigned int irqchip, + unsigned int pin) +{ + struct kvm_kernel_irqfd_resampler *resampler; + int gsi, idx; + + idx = srcu_read_lock(&kvm->irq_srcu); + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); + if (gsi != -1) { + list_for_each_entry_srcu(resampler, + &kvm->irqfds.resampler_list, link, + srcu_read_lock_held(&kvm->irq_srcu)) { + if (resampler->notifier.gsi == gsi) { + irqfd_resampler_notify(resampler); + srcu_read_unlock(&kvm->irq_srcu, idx); + return true; + } + } + } + srcu_read_unlock(&kvm->irq_srcu, idx); + + return false; +} + +/* + * create a host-wide workqueue for issuing deferred shutdown requests + * aggregated from all vm* instances. We need our own isolated + * queue to ease flushing work items when a VM exits. + */ +int kvm_irqfd_init(void) +{ + irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", WQ_PERCPU, 0); + if (!irqfd_cleanup_wq) + return -ENOMEM; + + return 0; +} + +void kvm_irqfd_exit(void) +{ + destroy_workqueue(irqfd_cleanup_wq); +} +#endif + +/* + * -------------------------------------------------------------------- + * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal. + * + * userspace can register a PIO/MMIO address with an eventfd for receiving + * notification when the memory has been touched. + * -------------------------------------------------------------------- + */ + +struct _ioeventfd { + struct list_head list; + u64 addr; + int length; + struct eventfd_ctx *eventfd; + u64 datamatch; + struct kvm_io_device dev; + u8 bus_idx; + bool wildcard; +}; + +static inline struct _ioeventfd * +to_ioeventfd(struct kvm_io_device *dev) +{ + return container_of(dev, struct _ioeventfd, dev); +} + +static void +ioeventfd_release(struct _ioeventfd *p) +{ + eventfd_ctx_put(p->eventfd); + list_del(&p->list); + kfree(p); +} + +static bool +ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) +{ + u64 _val; + + if (addr != p->addr) + /* address must be precise for a hit */ + return false; + + if (!p->length) + /* length = 0 means only look at the address, so always a hit */ + return true; + + if (len != p->length) + /* address-range must be precise for a hit */ + return false; + + if (p->wildcard) + /* all else equal, wildcard is always a hit */ + return true; + + /* otherwise, we have to actually compare the data */ + switch (len) { + case 1: + _val = get_unaligned((u8 *)val); + break; + case 2: + _val = get_unaligned((u16 *)val); + break; + case 4: + _val = get_unaligned((u32 *)val); + break; + case 8: + _val = get_unaligned((u64 *)val); + break; + default: + return false; + } + + return _val == p->datamatch; +} + +/* MMIO/PIO writes trigger an event if the addr/val match */ +static int +ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr, + int len, const void *val) +{ + struct _ioeventfd *p = to_ioeventfd(this); + + if (!ioeventfd_in_range(p, addr, len, val)) + return -EOPNOTSUPP; + + eventfd_signal(p->eventfd); + return 0; +} + +/* + * This function is called as KVM is completely shutting down. We do not + * need to worry about locking just nuke anything we have as quickly as possible + */ +static void +ioeventfd_destructor(struct kvm_io_device *this) +{ + struct _ioeventfd *p = to_ioeventfd(this); + + ioeventfd_release(p); +} + +static const struct kvm_io_device_ops ioeventfd_ops = { + .write = ioeventfd_write, + .destructor = ioeventfd_destructor, +}; + +/* assumes kvm->slots_lock held */ +static bool +ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) +{ + struct _ioeventfd *_p; + + list_for_each_entry(_p, &kvm->ioeventfds, list) + if (_p->bus_idx == p->bus_idx && + _p->addr == p->addr && + (!_p->length || !p->length || + (_p->length == p->length && + (_p->wildcard || p->wildcard || + _p->datamatch == p->datamatch)))) + return true; + + return false; +} + +static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags) +{ + if (flags & KVM_IOEVENTFD_FLAG_PIO) + return KVM_PIO_BUS; + if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY) + return KVM_VIRTIO_CCW_NOTIFY_BUS; + return KVM_MMIO_BUS; +} + +static int kvm_assign_ioeventfd_idx(struct kvm *kvm, + enum kvm_bus bus_idx, + struct kvm_ioeventfd *args) +{ + + struct eventfd_ctx *eventfd; + struct _ioeventfd *p; + int ret; + + eventfd = eventfd_ctx_fdget(args->fd); + if (IS_ERR(eventfd)) + return PTR_ERR(eventfd); + + p = kzalloc_obj(*p, GFP_KERNEL_ACCOUNT); + if (!p) { + ret = -ENOMEM; + goto fail; + } + + INIT_LIST_HEAD(&p->list); + p->addr = args->addr; + p->bus_idx = bus_idx; + p->length = args->len; + p->eventfd = eventfd; + + /* The datamatch feature is optional, otherwise this is a wildcard */ + if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) + p->datamatch = args->datamatch; + else + p->wildcard = true; + + mutex_lock(&kvm->slots_lock); + + /* Verify that there isn't a match already */ + if (ioeventfd_check_collision(kvm, p)) { + ret = -EEXIST; + goto unlock_fail; + } + + kvm_iodevice_init(&p->dev, &ioeventfd_ops); + + ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length, + &p->dev); + if (ret < 0) + goto unlock_fail; + + kvm_get_bus(kvm, bus_idx)->ioeventfd_count++; + list_add_tail(&p->list, &kvm->ioeventfds); + + mutex_unlock(&kvm->slots_lock); + + return 0; + +unlock_fail: + mutex_unlock(&kvm->slots_lock); + kfree(p); + +fail: + eventfd_ctx_put(eventfd); + + return ret; +} + +static int +kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx, + struct kvm_ioeventfd *args) +{ + struct _ioeventfd *p; + struct eventfd_ctx *eventfd; + struct kvm_io_bus *bus; + int ret = -ENOENT; + bool wildcard; + + eventfd = eventfd_ctx_fdget(args->fd); + if (IS_ERR(eventfd)) + return PTR_ERR(eventfd); + + wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); + + mutex_lock(&kvm->slots_lock); + + list_for_each_entry(p, &kvm->ioeventfds, list) { + if (p->bus_idx != bus_idx || + p->eventfd != eventfd || + p->addr != args->addr || + p->length != args->len || + p->wildcard != wildcard) + continue; + + if (!p->wildcard && p->datamatch != args->datamatch) + continue; + + kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); + bus = kvm_get_bus(kvm, bus_idx); + if (bus) + bus->ioeventfd_count--; + ret = 0; + break; + } + + mutex_unlock(&kvm->slots_lock); + + eventfd_ctx_put(eventfd); + + return ret; +} + +static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) +{ + enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags); + int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); + + if (!args->len && bus_idx == KVM_MMIO_BUS) + kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); + + return ret; +} + +static int +kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) +{ + enum kvm_bus bus_idx; + int ret; + + bus_idx = ioeventfd_bus_from_flags(args->flags); + /* must be natural-word sized, or 0 to ignore length */ + switch (args->len) { + case 0: + case 1: + case 2: + case 4: + case 8: + break; + default: + return -EINVAL; + } + + /* check for range overflow */ + if (args->addr + args->len < args->addr) + return -EINVAL; + + /* check for extra flags that we don't understand */ + if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) + return -EINVAL; + + /* ioeventfd with no length can't be combined with DATAMATCH */ + if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)) + return -EINVAL; + + ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args); + if (ret) + goto fail; + + /* When length is ignored, MMIO is also put on a separate bus, for + * faster lookups. + */ + if (!args->len && bus_idx == KVM_MMIO_BUS) { + ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); + if (ret < 0) + goto fast_fail; + } + + return 0; + +fast_fail: + kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); +fail: + return ret; +} + +int +kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) +{ + if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN) + return kvm_deassign_ioeventfd(kvm, args); + + return kvm_assign_ioeventfd(kvm, args); +} + +void +kvm_eventfd_init(struct kvm *kvm) +{ +#ifdef CONFIG_HAVE_KVM_IRQCHIP + spin_lock_init(&kvm->irqfds.lock); + INIT_LIST_HEAD(&kvm->irqfds.items); + INIT_LIST_HEAD(&kvm->irqfds.resampler_list); + mutex_init(&kvm->irqfds.resampler_lock); +#endif + INIT_LIST_HEAD(&kvm->ioeventfds); +} diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c new file mode 100644 index 000000000..db57c5766 --- /dev/null +++ b/virt/kvm/guest_memfd.c @@ -0,0 +1,1032 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/anon_inodes.h> +#include <linux/backing-dev.h> +#include <linux/falloc.h> +#include <linux/fs.h> +#include <linux/kvm_host.h> +#include <linux/mempolicy.h> +#include <linux/pseudo_fs.h> +#include <linux/pagemap.h> + +#include "kvm_mm.h" + +static struct vfsmount *kvm_gmem_mnt; + +/* + * A guest_memfd instance can be associated multiple VMs, each with its own + * "view" of the underlying physical memory. + * + * The gmem's inode is effectively the raw underlying physical storage, and is + * used to track properties of the physical memory, while each gmem file is + * effectively a single VM's view of that storage, and is used to track assets + * specific to its associated VM, e.g. memslots=>gmem bindings. + */ +struct gmem_file { + struct kvm *kvm; + struct xarray bindings; + struct list_head entry; +}; + +struct gmem_inode { + struct shared_policy policy; + struct inode vfs_inode; + struct list_head gmem_file_list; + + u64 flags; +}; + +static __always_inline struct gmem_inode *GMEM_I(struct inode *inode) +{ + return container_of(inode, struct gmem_inode, vfs_inode); +} + +#define kvm_gmem_for_each_file(f, inode) \ + list_for_each_entry(f, &GMEM_I(inode)->gmem_file_list, entry) + +/** + * folio_file_pfn - like folio_file_page, but return a pfn. + * @folio: The folio which contains this index. + * @index: The index we want to look up. + * + * Return: The pfn for this index. + */ +static inline kvm_pfn_t folio_file_pfn(struct folio *folio, pgoff_t index) +{ + return folio_pfn(folio) + (index & (folio_nr_pages(folio) - 1)); +} + +static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn) +{ + return gfn - slot->base_gfn + slot->gmem.pgoff; +} + +static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, + pgoff_t index, struct folio *folio) +{ +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE + kvm_pfn_t pfn = folio_file_pfn(folio, index); + gfn_t gfn = slot->base_gfn + index - slot->gmem.pgoff; + int rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio)); + if (rc) { + pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n", + index, gfn, pfn, rc); + return rc; + } +#endif + + return 0; +} + +/* + * Process @folio, which contains @gfn, so that the guest can use it. + * The folio must be locked and the gfn must be contained in @slot. + * On successful return the guest sees a zero page so as to avoid + * leaking host data and the up-to-date flag is set. + */ +static int kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, struct folio *folio) +{ + pgoff_t index; + + /* + * Preparing huge folios should always be safe, since it should + * be possible to split them later if needed. + * + * Right now the folio order is always going to be zero, but the + * code is ready for huge folios. The only assumption is that + * the base pgoff of memslots is naturally aligned with the + * requested page order, ensuring that huge folios can also use + * huge page table entries for GPA->HPA mapping. + * + * The order will be passed when creating the guest_memfd, and + * checked when creating memslots. + */ + WARN_ON(!IS_ALIGNED(slot->gmem.pgoff, folio_nr_pages(folio))); + index = kvm_gmem_get_index(slot, gfn); + index = ALIGN_DOWN(index, folio_nr_pages(folio)); + + return __kvm_gmem_prepare_folio(kvm, slot, index, folio); +} + +/* + * Returns a locked folio on success. The caller is responsible for + * setting the up-to-date flag before the memory is mapped into the guest. + * There is no backing storage for the memory, so the folio will remain + * up-to-date until it's removed. + * + * Ignore accessed, referenced, and dirty flags. The memory is + * unevictable and there is no storage to write back to. + */ +static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index) +{ + /* TODO: Support huge pages. */ + struct mempolicy *policy; + struct folio *folio; + + /* + * Fast-path: See if folio is already present in mapping to avoid + * policy_lookup. + */ + folio = filemap_lock_folio(inode->i_mapping, index); + if (!IS_ERR(folio)) + return folio; + + policy = mpol_shared_policy_lookup(&GMEM_I(inode)->policy, index); + folio = __filemap_get_folio_mpol(inode->i_mapping, index, + FGP_LOCK | FGP_CREAT, + mapping_gfp_mask(inode->i_mapping), policy); + mpol_cond_put(policy); + + /* + * External interfaces like kvm_gmem_get_pfn() support dealing + * with hugepages to a degree, but internally, guest_memfd currently + * assumes that all folios are order-0 and handling would need + * to be updated for anything otherwise (e.g. page-clearing + * operations). + */ + WARN_ON_ONCE(!IS_ERR(folio) && folio_order(folio)); + + return folio; +} + +static enum kvm_gfn_range_filter kvm_gmem_get_invalidate_filter(struct inode *inode) +{ + if (GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED) + return KVM_FILTER_SHARED; + + return KVM_FILTER_PRIVATE; +} + +static void __kvm_gmem_invalidate_start(struct gmem_file *f, pgoff_t start, + pgoff_t end, + enum kvm_gfn_range_filter attr_filter) +{ + bool flush = false, found_memslot = false; + struct kvm_memory_slot *slot; + struct kvm *kvm = f->kvm; + unsigned long index; + + xa_for_each_range(&f->bindings, index, slot, start, end - 1) { + pgoff_t pgoff = slot->gmem.pgoff; + + struct kvm_gfn_range gfn_range = { + .start = slot->base_gfn + max(pgoff, start) - pgoff, + .end = slot->base_gfn + min(pgoff + slot->npages, end) - pgoff, + .slot = slot, + .may_block = true, + .attr_filter = attr_filter, + }; + + if (!found_memslot) { + found_memslot = true; + + KVM_MMU_LOCK(kvm); + kvm_mmu_invalidate_start(kvm); + } + + flush |= kvm_mmu_unmap_gfn_range(kvm, &gfn_range); + } + + if (flush) + kvm_flush_remote_tlbs(kvm); + + if (found_memslot) + KVM_MMU_UNLOCK(kvm); +} + +static void kvm_gmem_invalidate_start(struct inode *inode, pgoff_t start, + pgoff_t end) +{ + enum kvm_gfn_range_filter attr_filter; + struct gmem_file *f; + + attr_filter = kvm_gmem_get_invalidate_filter(inode); + + kvm_gmem_for_each_file(f, inode) + __kvm_gmem_invalidate_start(f, start, end, attr_filter); +} + +static void __kvm_gmem_invalidate_end(struct gmem_file *f, pgoff_t start, + pgoff_t end) +{ + struct kvm *kvm = f->kvm; + + if (xa_find(&f->bindings, &start, end - 1, XA_PRESENT)) { + KVM_MMU_LOCK(kvm); + kvm_mmu_invalidate_end(kvm); + KVM_MMU_UNLOCK(kvm); + } +} + +static void kvm_gmem_invalidate_end(struct inode *inode, pgoff_t start, + pgoff_t end) +{ + struct gmem_file *f; + + kvm_gmem_for_each_file(f, inode) + __kvm_gmem_invalidate_end(f, start, end); +} + +static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len) +{ + pgoff_t start = offset >> PAGE_SHIFT; + pgoff_t end = (offset + len) >> PAGE_SHIFT; + + /* + * Bindings must be stable across invalidation to ensure the start+end + * are balanced. + */ + filemap_invalidate_lock(inode->i_mapping); + + kvm_gmem_invalidate_start(inode, start, end); + + truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1); + + kvm_gmem_invalidate_end(inode, start, end); + + filemap_invalidate_unlock(inode->i_mapping); + + return 0; +} + +static long kvm_gmem_allocate(struct inode *inode, loff_t offset, loff_t len) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t start, index, end; + int r; + + /* Dedicated guest is immutable by default. */ + if (offset + len > i_size_read(inode)) + return -EINVAL; + + filemap_invalidate_lock_shared(mapping); + + start = offset >> PAGE_SHIFT; + end = (offset + len) >> PAGE_SHIFT; + + r = 0; + for (index = start; index < end; ) { + struct folio *folio; + + if (signal_pending(current)) { + r = -EINTR; + break; + } + + folio = kvm_gmem_get_folio(inode, index); + if (IS_ERR(folio)) { + r = PTR_ERR(folio); + break; + } + + index = folio_next_index(folio); + + folio_unlock(folio); + folio_put(folio); + + /* 64-bit only, wrapping the index should be impossible. */ + if (WARN_ON_ONCE(!index)) + break; + + cond_resched(); + } + + filemap_invalidate_unlock_shared(mapping); + + return r; +} + +static long kvm_gmem_fallocate(struct file *file, int mode, loff_t offset, + loff_t len) +{ + int ret; + + if (!(mode & FALLOC_FL_KEEP_SIZE)) + return -EOPNOTSUPP; + + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) + return -EOPNOTSUPP; + + if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len)) + return -EINVAL; + + if (mode & FALLOC_FL_PUNCH_HOLE) + ret = kvm_gmem_punch_hole(file_inode(file), offset, len); + else + ret = kvm_gmem_allocate(file_inode(file), offset, len); + + if (!ret) + file_modified(file); + return ret; +} + +static int kvm_gmem_release(struct inode *inode, struct file *file) +{ + struct gmem_file *f = file->private_data; + struct kvm_memory_slot *slot; + struct kvm *kvm = f->kvm; + unsigned long index; + + /* + * Prevent concurrent attempts to *unbind* a memslot. This is the last + * reference to the file and thus no new bindings can be created, but + * dereferencing the slot for existing bindings needs to be protected + * against memslot updates, specifically so that unbind doesn't race + * and free the memslot (kvm_gmem_get_file() will return NULL). + * + * Since .release is called only when the reference count is zero, + * after which file_ref_get() and get_file_active() fail, + * kvm_gmem_get_pfn() cannot be using the file concurrently. + * file_ref_put() provides a full barrier, and get_file_active() the + * matching acquire barrier. + */ + mutex_lock(&kvm->slots_lock); + + filemap_invalidate_lock(inode->i_mapping); + + xa_for_each(&f->bindings, index, slot) + WRITE_ONCE(slot->gmem.file, NULL); + + /* + * All in-flight operations are gone and new bindings can be created. + * Zap all SPTEs pointed at by this file. Do not free the backing + * memory, as its lifetime is associated with the inode, not the file. + */ + __kvm_gmem_invalidate_start(f, 0, -1ul, + kvm_gmem_get_invalidate_filter(inode)); + __kvm_gmem_invalidate_end(f, 0, -1ul); + + list_del(&f->entry); + + filemap_invalidate_unlock(inode->i_mapping); + + mutex_unlock(&kvm->slots_lock); + + xa_destroy(&f->bindings); + kfree(f); + + kvm_put_kvm(kvm); + + return 0; +} + +static inline struct file *kvm_gmem_get_file(struct kvm_memory_slot *slot) +{ + /* + * Do not return slot->gmem.file if it has already been closed; + * there might be some time between the last fput() and when + * kvm_gmem_release() clears slot->gmem.file. + */ + return get_file_active(&slot->gmem.file); +} + +DEFINE_CLASS(gmem_get_file, struct file *, if (_T) fput(_T), + kvm_gmem_get_file(slot), struct kvm_memory_slot *slot); + +static bool kvm_gmem_supports_mmap(struct inode *inode) +{ + return GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_MMAP; +} + +static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf) +{ + struct inode *inode = file_inode(vmf->vma->vm_file); + struct folio *folio; + vm_fault_t ret = VM_FAULT_LOCKED; + + if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) + return VM_FAULT_SIGBUS; + + if (!(GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED)) + return VM_FAULT_SIGBUS; + + folio = kvm_gmem_get_folio(inode, vmf->pgoff); + if (IS_ERR(folio)) { + if (PTR_ERR(folio) == -EAGAIN) + return VM_FAULT_RETRY; + + return vmf_error(PTR_ERR(folio)); + } + + if (WARN_ON_ONCE(folio_test_large(folio))) { + ret = VM_FAULT_SIGBUS; + goto out_folio; + } + + if (!folio_test_uptodate(folio)) { + clear_highpage(folio_page(folio, 0)); + folio_mark_uptodate(folio); + } + + vmf->page = folio_file_page(folio, vmf->pgoff); + +out_folio: + if (ret != VM_FAULT_LOCKED) { + folio_unlock(folio); + folio_put(folio); + } + + return ret; +} + +#ifdef CONFIG_NUMA +static int kvm_gmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) +{ + struct inode *inode = file_inode(vma->vm_file); + + return mpol_set_shared_policy(&GMEM_I(inode)->policy, vma, mpol); +} + +static struct mempolicy *kvm_gmem_get_policy(struct vm_area_struct *vma, + unsigned long addr, pgoff_t *ilx) +{ + pgoff_t pgoff = vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT); + struct inode *inode = file_inode(vma->vm_file); + + *ilx = inode->i_ino; + + /* + * Return the memory policy for this index, or NULL if none is set. + * + * Returning NULL, e.g. instead of the current task's memory policy, is + * important for the .get_policy kernel ABI: it indicates that no + * explicit policy has been set via mbind() for this memory. The caller + * can then replace NULL with the default memory policy instead of the + * current task's memory policy. + */ + return mpol_shared_policy_lookup(&GMEM_I(inode)->policy, pgoff); +} +#endif /* CONFIG_NUMA */ + +static const struct vm_operations_struct kvm_gmem_vm_ops = { + .fault = kvm_gmem_fault_user_mapping, +#ifdef CONFIG_NUMA + .get_policy = kvm_gmem_get_policy, + .set_policy = kvm_gmem_set_policy, +#endif +}; + +static int kvm_gmem_mmap(struct file *file, struct vm_area_struct *vma) +{ + if (!kvm_gmem_supports_mmap(file_inode(file))) + return -ENODEV; + + if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) != + (VM_SHARED | VM_MAYSHARE)) { + return -EINVAL; + } + + vma->vm_ops = &kvm_gmem_vm_ops; + + return 0; +} + +static struct file_operations kvm_gmem_fops = { + .mmap = kvm_gmem_mmap, + .open = generic_file_open, + .release = kvm_gmem_release, + .fallocate = kvm_gmem_fallocate, +}; + +static int kvm_gmem_migrate_folio(struct address_space *mapping, + struct folio *dst, struct folio *src, + enum migrate_mode mode) +{ + WARN_ON_ONCE(1); + return -EINVAL; +} + +static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *folio) +{ + pgoff_t start, end; + + filemap_invalidate_lock_shared(mapping); + + start = folio->index; + end = start + folio_nr_pages(folio); + + kvm_gmem_invalidate_start(mapping->host, start, end); + + /* + * Do not truncate the range, what action is taken in response to the + * error is userspace's decision (assuming the architecture supports + * gracefully handling memory errors). If/when the guest attempts to + * access a poisoned page, kvm_gmem_get_pfn() will return -EHWPOISON, + * at which point KVM can either terminate the VM or propagate the + * error to userspace. + */ + + kvm_gmem_invalidate_end(mapping->host, start, end); + + filemap_invalidate_unlock_shared(mapping); + + return MF_DELAYED; +} + +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE +static void kvm_gmem_free_folio(struct folio *folio) +{ + struct page *page = folio_page(folio, 0); + kvm_pfn_t pfn = page_to_pfn(page); + int order = folio_order(folio); + + kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order)); +} +#endif + +static const struct address_space_operations kvm_gmem_aops = { + .dirty_folio = noop_dirty_folio, + .migrate_folio = kvm_gmem_migrate_folio, + .error_remove_folio = kvm_gmem_error_folio, +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE + .free_folio = kvm_gmem_free_folio, +#endif +}; + +static int kvm_gmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *attr) +{ + return -EINVAL; +} +static const struct inode_operations kvm_gmem_iops = { + .setattr = kvm_gmem_setattr, +}; + +bool __weak kvm_arch_supports_gmem_init_shared(struct kvm *kvm) +{ + return true; +} + +static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) +{ + static const char *name = "[kvm-gmem]"; + struct gmem_file *f; + struct inode *inode; + struct file *file; + int fd, err; + + fd = get_unused_fd_flags(0); + if (fd < 0) + return fd; + + f = kzalloc_obj(*f); + if (!f) { + err = -ENOMEM; + goto err_fd; + } + + /* __fput() will take care of fops_put(). */ + if (!fops_get(&kvm_gmem_fops)) { + err = -ENOENT; + goto err_gmem; + } + + inode = anon_inode_make_secure_inode(kvm_gmem_mnt->mnt_sb, name, NULL); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto err_fops; + } + + inode->i_op = &kvm_gmem_iops; + inode->i_mapping->a_ops = &kvm_gmem_aops; + inode->i_mode |= S_IFREG; + inode->i_size = size; + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_inaccessible(inode->i_mapping); + /* Unmovable mappings are supposed to be marked unevictable as well. */ + WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); + + GMEM_I(inode)->flags = flags; + + file = alloc_file_pseudo(inode, kvm_gmem_mnt, name, O_RDWR, &kvm_gmem_fops); + if (IS_ERR(file)) { + err = PTR_ERR(file); + goto err_inode; + } + + file->f_flags |= O_LARGEFILE; + file->private_data = f; + + kvm_get_kvm(kvm); + f->kvm = kvm; + xa_init(&f->bindings); + list_add(&f->entry, &GMEM_I(inode)->gmem_file_list); + + fd_install(fd, file); + return fd; + +err_inode: + iput(inode); +err_fops: + fops_put(&kvm_gmem_fops); +err_gmem: + kfree(f); +err_fd: + put_unused_fd(fd); + return err; +} + +int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args) +{ + loff_t size = args->size; + u64 flags = args->flags; + + if (flags & ~kvm_gmem_get_supported_flags(kvm)) + return -EINVAL; + + if (size <= 0 || !PAGE_ALIGNED(size)) + return -EINVAL; + + return __kvm_gmem_create(kvm, size, flags); +} + +int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int fd, uoff_t offset) +{ + uoff_t size = slot->npages << PAGE_SHIFT; + unsigned long start, end; + struct gmem_file *f; + struct inode *inode; + struct file *file; + int r = -EINVAL; + + BUILD_BUG_ON(sizeof(gpa_t) != sizeof(offset)); + BUILD_BUG_ON(sizeof(gfn_t) != sizeof(slot->gmem.pgoff)); + + file = fget(fd); + if (!file) + return -EBADF; + + if (file->f_op != &kvm_gmem_fops) + goto err; + + f = file->private_data; + if (f->kvm != kvm) + goto err; + + inode = file_inode(file); + + if (!PAGE_ALIGNED(offset) || offset + size > i_size_read(inode)) + goto err; + + filemap_invalidate_lock(inode->i_mapping); + + start = offset >> PAGE_SHIFT; + end = start + slot->npages; + + if (!xa_empty(&f->bindings) && + xa_find(&f->bindings, &start, end - 1, XA_PRESENT)) { + r = -EEXIST; + filemap_invalidate_unlock(inode->i_mapping); + goto err; + } + + /* + * memslots of flag KVM_MEM_GUEST_MEMFD are immutable to change, so + * kvm_gmem_bind() must occur on a new memslot. Because the memslot + * is not visible yet, kvm_gmem_get_pfn() is guaranteed to see the file. + */ + WRITE_ONCE(slot->gmem.file, file); + slot->gmem.pgoff = start; + if (kvm_gmem_supports_mmap(inode)) + slot->flags |= KVM_MEMSLOT_GMEM_ONLY; + + xa_store_range(&f->bindings, start, end - 1, slot, GFP_KERNEL); + filemap_invalidate_unlock(inode->i_mapping); + + /* + * Drop the reference to the file, even on success. The file pins KVM, + * not the other way 'round. Active bindings are invalidated if the + * file is closed before memslots are destroyed. + */ + r = 0; +err: + fput(file); + return r; +} + +static void __kvm_gmem_unbind(struct kvm_memory_slot *slot, struct gmem_file *f) +{ + unsigned long start = slot->gmem.pgoff; + unsigned long end = start + slot->npages; + + xa_store_range(&f->bindings, start, end - 1, NULL, GFP_KERNEL); + + /* + * synchronize_srcu(&kvm->srcu) ensured that kvm_gmem_get_pfn() + * cannot see this memslot. + */ + WRITE_ONCE(slot->gmem.file, NULL); +} + +void kvm_gmem_unbind(struct kvm_memory_slot *slot) +{ + /* + * Nothing to do if the underlying file was _already_ closed, as + * kvm_gmem_release() invalidates and nullifies all bindings. + */ + if (!slot->gmem.file) + return; + + CLASS(gmem_get_file, file)(slot); + + /* + * However, if the file is _being_ closed, then the bindings need to be + * removed as kvm_gmem_release() might not run until after the memslot + * is freed. Note, modifying the bindings is safe even though the file + * is dying as kvm_gmem_release() nullifies slot->gmem.file under + * slots_lock, and only puts its reference to KVM after destroying all + * bindings. I.e. reaching this point means kvm_gmem_release() hasn't + * yet destroyed the bindings or freed the gmem_file, and can't do so + * until the caller drops slots_lock. + */ + if (!file) { + __kvm_gmem_unbind(slot, slot->gmem.file->private_data); + return; + } + + filemap_invalidate_lock(file->f_mapping); + __kvm_gmem_unbind(slot, file->private_data); + filemap_invalidate_unlock(file->f_mapping); +} + +/* Returns a locked folio on success. */ +static struct folio *__kvm_gmem_get_pfn(struct file *file, + struct kvm_memory_slot *slot, + pgoff_t index, kvm_pfn_t *pfn, + int *max_order) +{ + struct file *slot_file = READ_ONCE(slot->gmem.file); + struct gmem_file *f = file->private_data; + struct folio *folio; + + if (file != slot_file) { + WARN_ON_ONCE(slot_file); + return ERR_PTR(-EFAULT); + } + + if (xa_load(&f->bindings, index) != slot) { + WARN_ON_ONCE(xa_load(&f->bindings, index)); + return ERR_PTR(-EIO); + } + + folio = kvm_gmem_get_folio(file_inode(file), index); + if (IS_ERR(folio)) + return folio; + + if (folio_test_hwpoison(folio)) { + folio_unlock(folio); + folio_put(folio); + return ERR_PTR(-EHWPOISON); + } + + *pfn = folio_file_pfn(folio, index); + if (max_order) + *max_order = 0; + + return folio; +} + +int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, kvm_pfn_t *pfn, struct page **page, + int *max_order) +{ + pgoff_t index = kvm_gmem_get_index(slot, gfn); + struct folio *folio; + int r = 0; + + CLASS(gmem_get_file, file)(slot); + if (!file) + return -EFAULT; + + folio = __kvm_gmem_get_pfn(file, slot, index, pfn, max_order); + if (IS_ERR(folio)) + return PTR_ERR(folio); + + if (!folio_test_uptodate(folio)) { + clear_highpage(folio_page(folio, 0)); + folio_mark_uptodate(folio); + } + + r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); + + folio_unlock(folio); + + if (!r) + *page = folio_file_page(folio, index); + else + folio_put(folio); + + return r; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); + +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE + +static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, + struct file *file, gfn_t gfn, struct page *src_page, + kvm_gmem_populate_cb post_populate, void *opaque) +{ + pgoff_t index = kvm_gmem_get_index(slot, gfn); + struct folio *folio; + kvm_pfn_t pfn; + int ret; + + filemap_invalidate_lock(file->f_mapping); + + folio = __kvm_gmem_get_pfn(file, slot, index, &pfn, NULL); + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); + goto out_unlock; + } + + folio_unlock(folio); + + if (!kvm_range_has_memory_attributes(kvm, gfn, gfn + 1, + KVM_MEMORY_ATTRIBUTE_PRIVATE, + KVM_MEMORY_ATTRIBUTE_PRIVATE)) { + ret = -EINVAL; + goto out_put_folio; + } + + ret = post_populate(kvm, gfn, pfn, src_page, opaque); + if (!ret) + folio_mark_uptodate(folio); + +out_put_folio: + folio_put(folio); +out_unlock: + filemap_invalidate_unlock(file->f_mapping); + return ret; +} + +long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, + long npages, bool may_writeback_src, + kvm_gmem_populate_cb post_populate, void *opaque) +{ + struct kvm_memory_slot *slot; + int ret = 0; + long i; + + lockdep_assert_held(&kvm->slots_lock); + + if (WARN_ON_ONCE(npages <= 0)) + return -EINVAL; + + if (WARN_ON_ONCE(!PAGE_ALIGNED(src))) + return -EINVAL; + + slot = gfn_to_memslot(kvm, start_gfn); + if (!kvm_slot_has_gmem(slot)) + return -EINVAL; + + CLASS(gmem_get_file, file)(slot); + if (!file) + return -EFAULT; + + npages = min_t(ulong, slot->npages - (start_gfn - slot->base_gfn), npages); + for (i = 0; i < npages; i++) { + struct page *src_page = NULL; + + if (signal_pending(current)) { + ret = -EINTR; + break; + } + + if (src) { + unsigned long uaddr = (unsigned long)src + i * PAGE_SIZE; + unsigned int flags = may_writeback_src ? FOLL_WRITE : 0; + + ret = get_user_pages_fast(uaddr, 1, flags, &src_page); + if (ret < 0) + break; + if (ret != 1) { + ret = -ENOMEM; + break; + } + } + + ret = __kvm_gmem_populate(kvm, slot, file, start_gfn + i, src_page, + post_populate, opaque); + + if (src_page) + put_page(src_page); + + if (ret) + break; + } + + return ret && !i ? ret : i; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_populate); +#endif + +static struct kmem_cache *kvm_gmem_inode_cachep; + +static void kvm_gmem_init_inode_once(void *__gi) +{ + struct gmem_inode *gi = __gi; + + /* + * Note! Don't initialize the inode with anything specific to the + * guest_memfd instance, or that might be specific to how the inode is + * used (from the VFS-layer's perspective). This hook is called only + * during the initial slab allocation, i.e. only fields/state that are + * idempotent across _all_ use of the inode _object_ can be initialized + * at this time! + */ + inode_init_once(&gi->vfs_inode); +} + +static struct inode *kvm_gmem_alloc_inode(struct super_block *sb) +{ + struct gmem_inode *gi; + + gi = alloc_inode_sb(sb, kvm_gmem_inode_cachep, GFP_KERNEL); + if (!gi) + return NULL; + + mpol_shared_policy_init(&gi->policy, NULL); + + gi->flags = 0; + INIT_LIST_HEAD(&gi->gmem_file_list); + return &gi->vfs_inode; +} + +static void kvm_gmem_destroy_inode(struct inode *inode) +{ + mpol_free_shared_policy(&GMEM_I(inode)->policy); +} + +static void kvm_gmem_free_inode(struct inode *inode) +{ + kmem_cache_free(kvm_gmem_inode_cachep, GMEM_I(inode)); +} + +static const struct super_operations kvm_gmem_super_operations = { + .statfs = simple_statfs, + .alloc_inode = kvm_gmem_alloc_inode, + .destroy_inode = kvm_gmem_destroy_inode, + .free_inode = kvm_gmem_free_inode, +}; + +static int kvm_gmem_init_fs_context(struct fs_context *fc) +{ + struct pseudo_fs_context *ctx; + + if (!init_pseudo(fc, GUEST_MEMFD_MAGIC)) + return -ENOMEM; + + ctx = fc->fs_private; + ctx->ops = &kvm_gmem_super_operations; + + return 0; +} + +static struct file_system_type kvm_gmem_fs = { + .name = "guest_memfd", + .init_fs_context = kvm_gmem_init_fs_context, + .kill_sb = kill_anon_super, +}; + +static int kvm_gmem_init_mount(void) +{ + kvm_gmem_mnt = kern_mount(&kvm_gmem_fs); + + if (IS_ERR(kvm_gmem_mnt)) + return PTR_ERR(kvm_gmem_mnt); + + kvm_gmem_mnt->mnt_flags |= MNT_NOEXEC; + return 0; +} + +int kvm_gmem_init(struct module *module) +{ + struct kmem_cache_args args = { + .align = 0, + .ctor = kvm_gmem_init_inode_once, + }; + int ret; + + kvm_gmem_fops.owner = module; + kvm_gmem_inode_cachep = kmem_cache_create("kvm_gmem_inode_cache", + sizeof(struct gmem_inode), + &args, SLAB_ACCOUNT); + if (!kvm_gmem_inode_cachep) + return -ENOMEM; + + ret = kvm_gmem_init_mount(); + if (ret) { + kmem_cache_destroy(kvm_gmem_inode_cachep); + return ret; + } + return 0; +} + +void kvm_gmem_exit(void) +{ + kern_unmount(kvm_gmem_mnt); + kvm_gmem_mnt = NULL; + rcu_barrier(); + kmem_cache_destroy(kvm_gmem_inode_cachep); +} diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c new file mode 100644 index 000000000..462c70621 --- /dev/null +++ b/virt/kvm/irqchip.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * irqchip.c: Common API for in kernel interrupt controllers + * Copyright (c) 2007, Intel Corporation. + * Copyright 2010 Red Hat, Inc. and/or its affiliates. + * Copyright (c) 2013, Alexander Graf <agraf@suse.de> + * + * This file is derived from virt/kvm/irq_comm.c. + * + * Authors: + * Yaozu (Eddie) Dong <Eddie.dong@intel.com> + * Alexander Graf <agraf@suse.de> + */ + +#include <linux/kvm_host.h> +#include <linux/slab.h> +#include <linux/srcu.h> +#include <linux/export.h> +#include <trace/events/kvm.h> + +int kvm_irq_map_gsi(struct kvm *kvm, + struct kvm_kernel_irq_routing_entry *entries, int gsi) +{ + struct kvm_irq_routing_table *irq_rt; + struct kvm_kernel_irq_routing_entry *e; + int n = 0; + + irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu, + lockdep_is_held(&kvm->irq_lock)); + if (irq_rt && gsi < irq_rt->nr_rt_entries) { + hlist_for_each_entry(e, &irq_rt->map[gsi], link) { + entries[n] = *e; + ++n; + } + } + + return n; +} + +int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin) +{ + struct kvm_irq_routing_table *irq_rt; + + irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); + return irq_rt->chip[irqchip][pin]; +} + +int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi) +{ + struct kvm_kernel_irq_routing_entry route; + + if (!kvm_arch_irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID)) + return -EINVAL; + + route.msi.address_lo = msi->address_lo; + route.msi.address_hi = msi->address_hi; + route.msi.data = msi->data; + route.msi.flags = msi->flags; + route.msi.devid = msi->devid; + + return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false); +} + +/* + * Return value: + * < 0 Interrupt was ignored (masked or not delivered for other reasons) + * = 0 Interrupt was coalesced (previous irq is still pending) + * > 0 Number of CPUs interrupt was delivered to + */ +int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level, + bool line_status) +{ + struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS]; + int ret = -1, i, idx; + + trace_kvm_set_irq(irq, level, irq_source_id); + + /* Not possible to detect if the guest uses the PIC or the + * IOAPIC. So set the bit in both. The guest will ignore + * writes to the unused one. + */ + idx = srcu_read_lock(&kvm->irq_srcu); + i = kvm_irq_map_gsi(kvm, irq_set, irq); + srcu_read_unlock(&kvm->irq_srcu, idx); + + while (i--) { + int r; + r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level, + line_status); + if (r < 0) + continue; + + ret = r + ((ret < 0) ? 0 : ret); + } + + return ret; +} + +static void free_irq_routing_table(struct kvm_irq_routing_table *rt) +{ + int i; + + if (!rt) + return; + + for (i = 0; i < rt->nr_rt_entries; ++i) { + struct kvm_kernel_irq_routing_entry *e; + struct hlist_node *n; + + hlist_for_each_entry_safe(e, n, &rt->map[i], link) { + hlist_del(&e->link); + kfree(e); + } + } + + kfree(rt); +} + +void kvm_free_irq_routing(struct kvm *kvm) +{ + /* Called only during vm destruction. Nobody can use the pointer + at this stage */ + struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing); + free_irq_routing_table(rt); +} + +static int setup_routing_entry(struct kvm *kvm, + struct kvm_irq_routing_table *rt, + struct kvm_kernel_irq_routing_entry *e, + const struct kvm_irq_routing_entry *ue) +{ + struct kvm_kernel_irq_routing_entry *ei; + int r; + u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES); + + /* + * Do not allow GSI to be mapped to the same irqchip more than once. + * Allow only one to one mapping between GSI and non-irqchip routing. + */ + hlist_for_each_entry(ei, &rt->map[gsi], link) + if (ei->type != KVM_IRQ_ROUTING_IRQCHIP || + ue->type != KVM_IRQ_ROUTING_IRQCHIP || + ue->u.irqchip.irqchip == ei->irqchip.irqchip) + return -EINVAL; + + e->gsi = gsi; + e->type = ue->type; + r = kvm_set_routing_entry(kvm, e, ue); + if (r) + return r; + if (e->type == KVM_IRQ_ROUTING_IRQCHIP) + rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi; + + hlist_add_head(&e->link, &rt->map[e->gsi]); + + return 0; +} + +void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm) +{ +} + +bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm) +{ + return true; +} + +int kvm_set_irq_routing(struct kvm *kvm, + const struct kvm_irq_routing_entry *ue, + unsigned nr, + unsigned flags) +{ + struct kvm_irq_routing_table *new, *old; + struct kvm_kernel_irq_routing_entry *e; + u32 i, j, nr_rt_entries = 0; + int r; + + for (i = 0; i < nr; ++i) { + if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES) + return -EINVAL; + nr_rt_entries = max(nr_rt_entries, ue[i].gsi); + } + + nr_rt_entries += 1; + + new = kzalloc_flex(*new, map, nr_rt_entries, GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->nr_rt_entries = nr_rt_entries; + for (i = 0; i < KVM_NR_IRQCHIPS; i++) + for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++) + new->chip[i][j] = -1; + + for (i = 0; i < nr; ++i) { + r = -ENOMEM; + e = kzalloc_obj(*e, GFP_KERNEL_ACCOUNT); + if (!e) + goto out; + + r = -EINVAL; + switch (ue->type) { + case KVM_IRQ_ROUTING_MSI: + if (ue->flags & ~KVM_MSI_VALID_DEVID) + goto free_entry; + break; + default: + if (ue->flags) + goto free_entry; + break; + } + r = setup_routing_entry(kvm, new, e, ue); + if (r) + goto free_entry; + ++ue; + } + + mutex_lock(&kvm->irq_lock); + old = rcu_dereference_protected(kvm->irq_routing, 1); + rcu_assign_pointer(kvm->irq_routing, new); + kvm_irq_routing_update(kvm); + kvm_arch_irq_routing_update(kvm); + mutex_unlock(&kvm->irq_lock); + + synchronize_srcu_expedited(&kvm->irq_srcu); + + new = old; + r = 0; + goto out; + +free_entry: + kfree(e); +out: + free_irq_routing_table(new); + + return r; +} + +/* + * Allocate empty IRQ routing by default so that additional setup isn't needed + * when userspace-driven IRQ routing is activated, and so that kvm->irq_routing + * is guaranteed to be non-NULL. + */ +int kvm_init_irq_routing(struct kvm *kvm) +{ + struct kvm_irq_routing_table *new; + int chip_size; + + new = kzalloc_flex(*new, map, 1, GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->nr_rt_entries = 1; + + chip_size = sizeof(int) * KVM_NR_IRQCHIPS * KVM_IRQCHIP_NUM_PINS; + memset(new->chip, -1, chip_size); + + RCU_INIT_POINTER(kvm->irq_routing, new); + + return 0; +} diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c new file mode 100644 index 000000000..e44c20c04 --- /dev/null +++ b/virt/kvm/kvm_main.c @@ -0,0 +1,6596 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel-based Virtual Machine (KVM) Hypervisor + * + * Copyright (C) 2006 Qumranet, Inc. + * Copyright 2010 Red Hat, Inc. and/or its affiliates. + * + * Authors: + * Avi Kivity <avi@qumranet.com> + * Yaniv Kamay <yaniv@qumranet.com> + */ + +#include <kvm/iodev.h> + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/percpu.h> +#include <linux/mm.h> +#include <linux/miscdevice.h> +#include <linux/vmalloc.h> +#include <linux/reboot.h> +#include <linux/debugfs.h> +#include <linux/highmem.h> +#include <linux/file.h> +#include <linux/syscore_ops.h> +#include <linux/cpu.h> +#include <linux/sched/signal.h> +#include <linux/sched/mm.h> +#include <linux/sched/stat.h> +#include <linux/cpumask.h> +#include <linux/smp.h> +#include <linux/anon_inodes.h> +#include <linux/profile.h> +#include <linux/kvm_para.h> +#include <linux/pagemap.h> +#include <linux/mman.h> +#include <linux/swap.h> +#include <linux/bitops.h> +#include <linux/spinlock.h> +#include <linux/compat.h> +#include <linux/srcu.h> +#include <linux/slab.h> +#include <linux/sort.h> +#include <linux/bsearch.h> +#include <linux/io.h> +#include <linux/lockdep.h> +#include <linux/kthread.h> +#include <linux/suspend.h> +#include <linux/rseq.h> + +#include <asm/processor.h> +#include <asm/ioctl.h> +#include <linux/uaccess.h> + +#include "coalesced_mmio.h" +#include "async_pf.h" +#include "kvm_mm.h" +#include "vfio.h" + +#include <trace/events/ipi.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/kvm.h> + +#include <linux/kvm_dirty_ring.h> + + +/* Worst case buffer size needed for holding an integer. */ +#define ITOA_MAX_LEN 12 + +MODULE_AUTHOR("Qumranet"); +MODULE_DESCRIPTION("Kernel-based Virtual Machine (KVM) Hypervisor"); +MODULE_LICENSE("GPL"); + +/* Architectures should define their poll value according to the halt latency */ +unsigned int __read_mostly halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT; +module_param(halt_poll_ns, uint, 0644); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns); + +/* Default doubles per-vcpu halt_poll_ns. */ +unsigned int __read_mostly halt_poll_ns_grow = 2; +module_param(halt_poll_ns_grow, uint, 0644); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_grow); + +/* The start value to grow halt_poll_ns from */ +unsigned int __read_mostly halt_poll_ns_grow_start = 10000; /* 10us */ +module_param(halt_poll_ns_grow_start, uint, 0644); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_grow_start); + +/* Default halves per-vcpu halt_poll_ns. */ +unsigned int __read_mostly halt_poll_ns_shrink = 2; +module_param(halt_poll_ns_shrink, uint, 0644); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink); + +/* + * Allow direct access (from KVM or the CPU) without MMU notifier protection + * to unpinned pages. + */ +static bool __ro_after_init allow_unsafe_mappings; +module_param(allow_unsafe_mappings, bool, 0444); + +/* + * Ordering of locks: + * + * kvm->lock --> kvm->slots_lock --> kvm->irq_lock + */ + +DEFINE_MUTEX(kvm_lock); +LIST_HEAD(vm_list); + +static struct kmem_cache *kvm_vcpu_cache; + +static __read_mostly struct preempt_ops kvm_preempt_ops; +static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu); + +static struct dentry *kvm_debugfs_dir; + +static const struct file_operations stat_fops_per_vm; + +static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg); +#ifdef CONFIG_KVM_COMPAT +static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg); +#define KVM_COMPAT(c) .compat_ioctl = (c) +#else +/* + * For architectures that don't implement a compat infrastructure, + * adopt a double line of defense: + * - Prevent a compat task from opening /dev/kvm + * - If the open has been done by a 64bit task, and the KVM fd + * passed to a compat task, let the ioctls fail. + */ +static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg) { return -EINVAL; } + +static int kvm_no_compat_open(struct inode *inode, struct file *file) +{ + return is_compat_task() ? -ENODEV : 0; +} +#define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl, \ + .open = kvm_no_compat_open +#endif + +static void kvm_io_bus_destroy(struct kvm_io_bus *bus); + +#define KVM_EVENT_CREATE_VM 0 +#define KVM_EVENT_DESTROY_VM 1 +static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); +static unsigned long long kvm_createvm_count; +static unsigned long long kvm_active_vms; + +static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask); + +__weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm) +{ +} + +/* + * Switches to specified vcpu, until a matching vcpu_put() + */ +void vcpu_load(struct kvm_vcpu *vcpu) +{ + int cpu = get_cpu(); + + __this_cpu_write(kvm_running_vcpu, vcpu); + preempt_notifier_register(&vcpu->preempt_notifier); + kvm_arch_vcpu_load(vcpu, cpu); + put_cpu(); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(vcpu_load); + +void vcpu_put(struct kvm_vcpu *vcpu) +{ + preempt_disable(); + kvm_arch_vcpu_put(vcpu); + preempt_notifier_unregister(&vcpu->preempt_notifier); + __this_cpu_write(kvm_running_vcpu, NULL); + preempt_enable(); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(vcpu_put); + +/* TODO: merge with kvm_arch_vcpu_should_kick */ +static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req) +{ + int mode = kvm_vcpu_exiting_guest_mode(vcpu); + + /* + * We need to wait for the VCPU to reenable interrupts and get out of + * READING_SHADOW_PAGE_TABLES mode. + */ + if (req & KVM_REQUEST_WAIT) + return mode != OUTSIDE_GUEST_MODE; + + /* + * Need to kick a running VCPU, but otherwise there is nothing to do. + */ + return mode == IN_GUEST_MODE; +} + +static void ack_kick(void *_completed) +{ +} + +static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait) +{ + if (cpumask_empty(cpus)) + return false; + + smp_call_function_many(cpus, ack_kick, NULL, wait); + return true; +} + +static void kvm_make_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req, + struct cpumask *tmp, int current_cpu) +{ + int cpu; + + if (likely(!(req & KVM_REQUEST_NO_ACTION))) + __kvm_make_request(req, vcpu); + + if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu)) + return; + + /* + * Note, the vCPU could get migrated to a different pCPU at any point + * after kvm_request_needs_ipi(), which could result in sending an IPI + * to the previous pCPU. But, that's OK because the purpose of the IPI + * is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is + * satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES + * after this point is also OK, as the requirement is only that KVM wait + * for vCPUs that were reading SPTEs _before_ any changes were + * finalized. See kvm_vcpu_kick() for more details on handling requests. + */ + if (kvm_request_needs_ipi(vcpu, req)) { + cpu = READ_ONCE(vcpu->cpu); + if (cpu != -1 && cpu != current_cpu) + __cpumask_set_cpu(cpu, tmp); + } +} + +bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req, + unsigned long *vcpu_bitmap) +{ + struct kvm_vcpu *vcpu; + struct cpumask *cpus; + int i, me; + bool called; + + me = get_cpu(); + + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + + for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) { + vcpu = kvm_get_vcpu(kvm, i); + if (!vcpu) + continue; + kvm_make_vcpu_request(vcpu, req, cpus, me); + } + + called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); + put_cpu(); + + return called; +} + +bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) +{ + struct kvm_vcpu *vcpu; + struct cpumask *cpus; + unsigned long i; + bool called; + int me; + + me = get_cpu(); + + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + + kvm_for_each_vcpu(i, vcpu, kvm) + kvm_make_vcpu_request(vcpu, req, cpus, me); + + called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); + put_cpu(); + + return called; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_make_all_cpus_request); + +void kvm_flush_remote_tlbs(struct kvm *kvm) +{ + ++kvm->stat.generic.remote_tlb_flush_requests; + + /* + * We want to publish modifications to the page tables before reading + * mode. Pairs with a memory barrier in arch-specific code. + * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest + * and smp_mb in walk_shadow_page_lockless_begin/end. + * - powerpc: smp_mb in kvmppc_prepare_to_enter. + * + * There is already an smp_mb__after_atomic() before + * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that + * barrier here. + */ + if (!kvm_arch_flush_remote_tlbs(kvm) + || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH)) + ++kvm->stat.generic.remote_tlb_flush; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_flush_remote_tlbs); + +void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages) +{ + if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages)) + return; + + /* + * Fall back to a flushing entire TLBs if the architecture range-based + * TLB invalidation is unsupported or can't be performed for whatever + * reason. + */ + kvm_flush_remote_tlbs(kvm); +} + +void kvm_flush_remote_tlbs_memslot(struct kvm *kvm, + const struct kvm_memory_slot *memslot) +{ + /* + * All current use cases for flushing the TLBs for a specific memslot + * are related to dirty logging, and many do the TLB flush out of + * mmu_lock. The interaction between the various operations on memslot + * must be serialized by slots_lock to ensure the TLB flush from one + * operation is observed by any other operation on the same memslot. + */ + lockdep_assert_held(&kvm->slots_lock); + kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages); +} + +static void kvm_flush_shadow_all(struct kvm *kvm) +{ + kvm_arch_flush_shadow_all(kvm); + kvm_arch_guest_memory_reclaimed(kvm); +} + +#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE +static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc, + gfp_t gfp_flags) +{ + void *page; + + gfp_flags |= mc->gfp_zero; + + if (mc->kmem_cache) + return kmem_cache_alloc(mc->kmem_cache, gfp_flags); + + page = (void *)__get_free_page(gfp_flags); + if (page && mc->init_value) + memset64(page, mc->init_value, PAGE_SIZE / sizeof(u64)); + return page; +} + +int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min) +{ + gfp_t gfp = mc->gfp_custom ? mc->gfp_custom : GFP_KERNEL_ACCOUNT; + void *obj; + + if (mc->nobjs >= min) + return 0; + + if (unlikely(!mc->objects)) { + if (WARN_ON_ONCE(!capacity)) + return -EIO; + + /* + * Custom init values can be used only for page allocations, + * and obviously conflict with __GFP_ZERO. + */ + if (WARN_ON_ONCE(mc->init_value && (mc->kmem_cache || mc->gfp_zero))) + return -EIO; + + mc->objects = kvmalloc_array(capacity, sizeof(void *), gfp); + if (!mc->objects) + return -ENOMEM; + + mc->capacity = capacity; + } + + /* It is illegal to request a different capacity across topups. */ + if (WARN_ON_ONCE(mc->capacity != capacity)) + return -EIO; + + while (mc->nobjs < mc->capacity) { + obj = mmu_memory_cache_alloc_obj(mc, gfp); + if (!obj) + return mc->nobjs >= min ? 0 : -ENOMEM; + mc->objects[mc->nobjs++] = obj; + } + return 0; +} + +int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min) +{ + return __kvm_mmu_topup_memory_cache(mc, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, min); +} + +int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc) +{ + return mc->nobjs; +} + +void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) +{ + while (mc->nobjs) { + if (mc->kmem_cache) + kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]); + else + free_page((unsigned long)mc->objects[--mc->nobjs]); + } + + kvfree(mc->objects); + + mc->objects = NULL; + mc->capacity = 0; +} + +void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc) +{ + void *p; + + if (WARN_ON(!mc->nobjs)) + p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT); + else + p = mc->objects[--mc->nobjs]; + BUG_ON(!p); + return p; +} +#endif + +static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) +{ + mutex_init(&vcpu->mutex); + vcpu->cpu = -1; + vcpu->kvm = kvm; + vcpu->vcpu_id = id; + vcpu->pid = NULL; + rwlock_init(&vcpu->pid_lock); +#ifndef __KVM_HAVE_ARCH_WQP + rcuwait_init(&vcpu->wait); +#endif + kvm_async_pf_vcpu_init(vcpu); + + kvm_vcpu_set_in_spin_loop(vcpu, false); + kvm_vcpu_set_dy_eligible(vcpu, false); + vcpu->preempted = false; + vcpu->ready = false; + preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); + vcpu->last_used_slot = NULL; + + /* Fill the stats id string for the vcpu */ + snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d", + task_pid_nr(current), id); +} + +static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu) +{ + kvm_arch_vcpu_destroy(vcpu); + kvm_dirty_ring_free(&vcpu->dirty_ring); + + /* + * No need for rcu_read_lock as VCPU_RUN is the only place that changes + * the vcpu->pid pointer, and at destruction time all file descriptors + * are already gone. + */ + put_pid(vcpu->pid); + + free_page((unsigned long)vcpu->run); + kmem_cache_free(kvm_vcpu_cache, vcpu); +} + +void kvm_destroy_vcpus(struct kvm *kvm) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + kvm_for_each_vcpu(i, vcpu, kvm) { + kvm_vcpu_destroy(vcpu); + xa_erase(&kvm->vcpu_array, i); + + /* + * Assert that the vCPU isn't visible in any way, to ensure KVM + * doesn't trigger a use-after-free if destroying vCPUs results + * in VM-wide request, e.g. to flush remote TLBs when tearing + * down MMUs, or to mark the VM dead if a KVM_BUG_ON() fires. + */ + WARN_ON_ONCE(xa_load(&kvm->vcpu_array, i) || kvm_get_vcpu(kvm, i)); + } + + atomic_set(&kvm->online_vcpus, 0); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_destroy_vcpus); + +static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) +{ + return container_of(mn, struct kvm, mmu_notifier); +} + +typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); + +typedef void (*on_lock_fn_t)(struct kvm *kvm); + +struct kvm_mmu_notifier_range { + /* + * 64-bit addresses, as KVM notifiers can operate on host virtual + * addresses (unsigned long) and guest physical addresses (64-bit). + */ + u64 start; + u64 end; + union kvm_mmu_notifier_arg arg; + gfn_handler_t handler; + on_lock_fn_t on_lock; + bool flush_on_ret; + bool may_block; + bool lockless; +}; + +/* + * The inner-most helper returns a tuple containing the return value from the + * arch- and action-specific handler, plus a flag indicating whether or not at + * least one memslot was found, i.e. if the handler found guest memory. + * + * Note, most notifiers are averse to booleans, so even though KVM tracks the + * return from arch code as a bool, outer helpers will cast it to an int. :-( + */ +typedef struct kvm_mmu_notifier_return { + bool ret; + bool found_memslot; +} kvm_mn_ret_t; + +/* + * Use a dedicated stub instead of NULL to indicate that there is no callback + * function/handler. The compiler technically can't guarantee that a real + * function will have a non-zero address, and so it will generate code to + * check for !NULL, whereas comparing against a stub will be elided at compile + * time (unless the compiler is getting long in the tooth, e.g. gcc 4.9). + */ +static void kvm_null_fn(void) +{ + +} +#define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn) + +/* Iterate over each memslot intersecting [start, last] (inclusive) range */ +#define kvm_for_each_memslot_in_hva_range(node, slots, start, last) \ + for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \ + node; \ + node = interval_tree_iter_next(node, start, last)) \ + +static __always_inline kvm_mn_ret_t kvm_handle_hva_range(struct kvm *kvm, + const struct kvm_mmu_notifier_range *range) +{ + struct kvm_mmu_notifier_return r = { + .ret = false, + .found_memslot = false, + }; + struct kvm_gfn_range gfn_range; + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + int i, idx; + + if (WARN_ON_ONCE(range->end <= range->start)) + return r; + + /* A null handler is allowed if and only if on_lock() is provided. */ + if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) && + IS_KVM_NULL_FN(range->handler))) + return r; + + /* on_lock will never be called for lockless walks */ + if (WARN_ON_ONCE(range->lockless && !IS_KVM_NULL_FN(range->on_lock))) + return r; + + idx = srcu_read_lock(&kvm->srcu); + + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { + struct interval_tree_node *node; + + slots = __kvm_memslots(kvm, i); + kvm_for_each_memslot_in_hva_range(node, slots, + range->start, range->end - 1) { + unsigned long hva_start, hva_end; + + slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]); + hva_start = max_t(unsigned long, range->start, slot->userspace_addr); + hva_end = min_t(unsigned long, range->end, + slot->userspace_addr + (slot->npages << PAGE_SHIFT)); + + /* + * To optimize for the likely case where the address + * range is covered by zero or one memslots, don't + * bother making these conditional (to avoid writes on + * the second or later invocation of the handler). + */ + gfn_range.arg = range->arg; + gfn_range.may_block = range->may_block; + /* + * HVA-based notifications aren't relevant to private + * mappings as they don't have a userspace mapping. + */ + gfn_range.attr_filter = KVM_FILTER_SHARED; + + /* + * {gfn(page) | page intersects with [hva_start, hva_end)} = + * {gfn_start, gfn_start+1, ..., gfn_end-1}. + */ + gfn_range.start = hva_to_gfn_memslot(hva_start, slot); + gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot); + gfn_range.slot = slot; + gfn_range.lockless = range->lockless; + + if (!r.found_memslot) { + r.found_memslot = true; + if (!range->lockless) { + KVM_MMU_LOCK(kvm); + if (!IS_KVM_NULL_FN(range->on_lock)) + range->on_lock(kvm); + + if (IS_KVM_NULL_FN(range->handler)) + goto mmu_unlock; + } + } + r.ret |= range->handler(kvm, &gfn_range); + } + } + + if (range->flush_on_ret && r.ret) + kvm_flush_remote_tlbs(kvm); + +mmu_unlock: + if (r.found_memslot && !range->lockless) + KVM_MMU_UNLOCK(kvm); + + srcu_read_unlock(&kvm->srcu, idx); + + return r; +} + +static __always_inline bool kvm_age_hva_range(struct mmu_notifier *mn, + unsigned long start, unsigned long end, gfn_handler_t handler, + bool flush_on_ret) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_mmu_notifier_range range = { + .start = start, + .end = end, + .handler = handler, + .on_lock = (void *)kvm_null_fn, + .flush_on_ret = flush_on_ret, + .may_block = false, + .lockless = IS_ENABLED(CONFIG_KVM_MMU_LOCKLESS_AGING), + }; + + return kvm_handle_hva_range(kvm, &range).ret; +} + +static __always_inline bool kvm_age_hva_range_no_flush(struct mmu_notifier *mn, + unsigned long start, unsigned long end, gfn_handler_t handler) +{ + return kvm_age_hva_range(mn, start, end, handler, false); +} + +void kvm_mmu_invalidate_start(struct kvm *kvm) +{ + lockdep_assert_held_write(&kvm->mmu_lock); + /* + * The count increase must become visible at unlock time as no + * spte can be established without taking the mmu_lock and + * count is also read inside the mmu_lock critical section. + */ + kvm->mmu_invalidate_in_progress++; + + if (likely(kvm->mmu_invalidate_in_progress == 1)) { + kvm->mmu_invalidate_range_start = INVALID_GPA; + kvm->mmu_invalidate_range_end = INVALID_GPA; + } +} + +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) +{ + lockdep_assert_held_write(&kvm->mmu_lock); + + WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress); + + if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) { + kvm->mmu_invalidate_range_start = start; + kvm->mmu_invalidate_range_end = end; + } else { + /* + * Fully tracking multiple concurrent ranges has diminishing + * returns. Keep things simple and just find the minimal range + * which includes the current and new ranges. As there won't be + * enough information to subtract a range after its invalidate + * completes, any ranges invalidated concurrently will + * accumulate and persist until all outstanding invalidates + * complete. + */ + kvm->mmu_invalidate_range_start = + min(kvm->mmu_invalidate_range_start, start); + kvm->mmu_invalidate_range_end = + max(kvm->mmu_invalidate_range_end, end); + } +} + +bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +{ + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); + return kvm_unmap_gfn_range(kvm, range); +} + +static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, + const struct mmu_notifier_range *range) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_mmu_notifier_range hva_range = { + .start = range->start, + .end = range->end, + .handler = kvm_mmu_unmap_gfn_range, + .on_lock = kvm_mmu_invalidate_start, + .flush_on_ret = true, + .may_block = mmu_notifier_range_blockable(range), + }; + + trace_kvm_unmap_hva_range(range->start, range->end); + + /* + * Prevent memslot modification between range_start() and range_end() + * so that conditionally locking provides the same result in both + * functions. Without that guarantee, the mmu_invalidate_in_progress + * adjustments will be imbalanced. + * + * Pairs with the decrement in range_end(). + */ + spin_lock(&kvm->mn_invalidate_lock); + kvm->mn_active_invalidate_count++; + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e. + * before acquiring mmu_lock, to avoid holding mmu_lock while acquiring + * each cache's lock. There are relatively few caches in existence at + * any given time, and the caches themselves can check for hva overlap, + * i.e. don't need to rely on memslot overlap checks for performance. + * Because this runs without holding mmu_lock, the pfn caches must use + * mn_active_invalidate_count (see above) instead of + * mmu_invalidate_in_progress. + */ + gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end); + + /* + * If one or more memslots were found and thus zapped, notify arch code + * that guest memory has been reclaimed. This needs to be done *after* + * dropping mmu_lock, as x86's reclaim path is slooooow. + */ + if (kvm_handle_hva_range(kvm, &hva_range).found_memslot) + kvm_arch_guest_memory_reclaimed(kvm); + + return 0; +} + +void kvm_mmu_invalidate_end(struct kvm *kvm) +{ + lockdep_assert_held_write(&kvm->mmu_lock); + + /* + * This sequence increase will notify the kvm page fault that + * the page that is going to be mapped in the spte could have + * been freed. + */ + kvm->mmu_invalidate_seq++; + smp_wmb(); + /* + * The above sequence increase must be visible before the + * below count decrease, which is ensured by the smp_wmb above + * in conjunction with the smp_rmb in mmu_invalidate_retry(). + */ + kvm->mmu_invalidate_in_progress--; + KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm); + + /* + * Assert that at least one range was added between start() and end(). + * Not adding a range isn't fatal, but it is a KVM bug. + */ + WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA); +} + +static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, + const struct mmu_notifier_range *range) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_mmu_notifier_range hva_range = { + .start = range->start, + .end = range->end, + .handler = (void *)kvm_null_fn, + .on_lock = kvm_mmu_invalidate_end, + .flush_on_ret = false, + .may_block = mmu_notifier_range_blockable(range), + }; + bool wake; + + kvm_handle_hva_range(kvm, &hva_range); + + /* Pairs with the increment in range_start(). */ + spin_lock(&kvm->mn_invalidate_lock); + if (!WARN_ON_ONCE(!kvm->mn_active_invalidate_count)) + --kvm->mn_active_invalidate_count; + wake = !kvm->mn_active_invalidate_count; + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * There can only be one waiter, since the wait happens under + * slots_lock. + */ + if (wake) + rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait); +} + +static bool kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, + struct mm_struct *mm, unsigned long start, unsigned long end) +{ + trace_kvm_age_hva(start, end); + + return kvm_age_hva_range(mn, start, end, kvm_age_gfn, + !IS_ENABLED(CONFIG_KVM_ELIDE_TLB_FLUSH_IF_YOUNG)); +} + +static bool kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, + struct mm_struct *mm, unsigned long start, unsigned long end) +{ + trace_kvm_age_hva(start, end); + + /* + * Even though we do not flush TLB, this will still adversely + * affect performance on pre-Haswell Intel EPT, where there is + * no EPT Access Bit to clear so that we have to tear down EPT + * tables instead. If we find this unacceptable, we can always + * add a parameter to kvm_age_hva so that it effectively doesn't + * do anything on clear_young. + * + * Also note that currently we never issue secondary TLB flushes + * from clear_young, leaving this job up to the regular system + * cadence. If we find this inaccurate, we might come up with a + * more sophisticated heuristic later. + */ + return kvm_age_hva_range_no_flush(mn, start, end, kvm_age_gfn); +} + +static bool kvm_mmu_notifier_test_young(struct mmu_notifier *mn, + struct mm_struct *mm, unsigned long address) +{ + trace_kvm_test_age_hva(address); + + return kvm_age_hva_range_no_flush(mn, address, address + 1, + kvm_test_age_gfn); +} + +static void kvm_mmu_notifier_release(struct mmu_notifier *mn, + struct mm_struct *mm) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + int idx; + + idx = srcu_read_lock(&kvm->srcu); + kvm_flush_shadow_all(kvm); + srcu_read_unlock(&kvm->srcu, idx); +} + +static const struct mmu_notifier_ops kvm_mmu_notifier_ops = { + .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start, + .invalidate_range_end = kvm_mmu_notifier_invalidate_range_end, + .clear_flush_young = kvm_mmu_notifier_clear_flush_young, + .clear_young = kvm_mmu_notifier_clear_young, + .test_young = kvm_mmu_notifier_test_young, + .release = kvm_mmu_notifier_release, +}; + +static int kvm_init_mmu_notifier(struct kvm *kvm) +{ + kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops; + return mmu_notifier_register(&kvm->mmu_notifier, current->mm); +} + +#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER +static int kvm_pm_notifier_call(struct notifier_block *bl, + unsigned long state, + void *unused) +{ + struct kvm *kvm = container_of(bl, struct kvm, pm_notifier); + + return kvm_arch_pm_notifier(kvm, state); +} + +static void kvm_init_pm_notifier(struct kvm *kvm) +{ + kvm->pm_notifier.notifier_call = kvm_pm_notifier_call; + /* Suspend KVM before we suspend ftrace, RCU, etc. */ + kvm->pm_notifier.priority = INT_MAX; + register_pm_notifier(&kvm->pm_notifier); +} + +static void kvm_destroy_pm_notifier(struct kvm *kvm) +{ + unregister_pm_notifier(&kvm->pm_notifier); +} +#else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */ +static void kvm_init_pm_notifier(struct kvm *kvm) +{ +} + +static void kvm_destroy_pm_notifier(struct kvm *kvm) +{ +} +#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */ + +static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot) +{ + if (!memslot->dirty_bitmap) + return; + + vfree(memslot->dirty_bitmap); + memslot->dirty_bitmap = NULL; +} + +/* This does not remove the slot from struct kvm_memslots data structures */ +static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + if (slot->flags & KVM_MEM_GUEST_MEMFD) + kvm_gmem_unbind(slot); + + kvm_destroy_dirty_bitmap(slot); + + kvm_arch_free_memslot(kvm, slot); + + kfree(slot); +} + +static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots) +{ + struct hlist_node *idnode; + struct kvm_memory_slot *memslot; + int bkt; + + /* + * The same memslot objects live in both active and inactive sets, + * arbitrarily free using index '1' so the second invocation of this + * function isn't operating over a structure with dangling pointers + * (even though this function isn't actually touching them). + */ + if (!slots->node_idx) + return; + + hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1]) + kvm_free_memslot(kvm, memslot); +} + +static umode_t kvm_stats_debugfs_mode(const struct kvm_stats_desc *desc) +{ + switch (desc->flags & KVM_STATS_TYPE_MASK) { + case KVM_STATS_TYPE_INSTANT: + return 0444; + case KVM_STATS_TYPE_CUMULATIVE: + case KVM_STATS_TYPE_PEAK: + default: + return 0644; + } +} + + +static void kvm_destroy_vm_debugfs(struct kvm *kvm) +{ + int i; + int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + + kvm_vcpu_stats_header.num_desc; + + if (IS_ERR(kvm->debugfs_dentry)) + return; + + debugfs_remove_recursive(kvm->debugfs_dentry); + + if (kvm->debugfs_stat_data) { + for (i = 0; i < kvm_debugfs_num_entries; i++) + kfree(kvm->debugfs_stat_data[i]); + kfree(kvm->debugfs_stat_data); + } +} + +static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname) +{ + static DEFINE_MUTEX(kvm_debugfs_lock); + struct dentry *dent; + char dir_name[ITOA_MAX_LEN * 2]; + struct kvm_stat_data *stat_data; + const struct kvm_stats_desc *pdesc; + int i, ret = -ENOMEM; + int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + + kvm_vcpu_stats_header.num_desc; + + if (!debugfs_initialized()) + return 0; + + snprintf(dir_name, sizeof(dir_name), "%d-%s", task_pid_nr(current), fdname); + mutex_lock(&kvm_debugfs_lock); + dent = debugfs_lookup(dir_name, kvm_debugfs_dir); + if (dent) { + pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name); + dput(dent); + mutex_unlock(&kvm_debugfs_lock); + return 0; + } + dent = debugfs_create_dir(dir_name, kvm_debugfs_dir); + mutex_unlock(&kvm_debugfs_lock); + if (IS_ERR(dent)) + return 0; + + kvm->debugfs_dentry = dent; + kvm->debugfs_stat_data = kzalloc_objs(*kvm->debugfs_stat_data, + kvm_debugfs_num_entries, + GFP_KERNEL_ACCOUNT); + if (!kvm->debugfs_stat_data) + goto out_err; + + for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) { + pdesc = &kvm_vm_stats_desc[i]; + stat_data = kzalloc_obj(*stat_data, GFP_KERNEL_ACCOUNT); + if (!stat_data) + goto out_err; + + stat_data->kvm = kvm; + stat_data->desc = pdesc; + stat_data->kind = KVM_STAT_VM; + kvm->debugfs_stat_data[i] = stat_data; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm->debugfs_dentry, stat_data, + &stat_fops_per_vm); + } + + for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) { + pdesc = &kvm_vcpu_stats_desc[i]; + stat_data = kzalloc_obj(*stat_data, GFP_KERNEL_ACCOUNT); + if (!stat_data) + goto out_err; + + stat_data->kvm = kvm; + stat_data->desc = pdesc; + stat_data->kind = KVM_STAT_VCPU; + kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm->debugfs_dentry, stat_data, + &stat_fops_per_vm); + } + + kvm_arch_create_vm_debugfs(kvm); + return 0; +out_err: + kvm_destroy_vm_debugfs(kvm); + return ret; +} + +/* + * Called just after removing the VM from the vm_list, but before doing any + * other destruction. + */ +void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm) +{ +} + +/* + * Called after per-vm debugfs created. When called kvm->debugfs_dentry should + * be setup already, so we can create arch-specific debugfs entries under it. + * Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so + * a per-arch destroy interface is not needed. + */ +void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm) +{ +} + +/* Called only on cleanup and destruction paths when there are no users. */ +static inline struct kvm_io_bus *kvm_get_bus_for_destruction(struct kvm *kvm, + enum kvm_bus idx) +{ + return rcu_dereference_protected(kvm->buses[idx], + !refcount_read(&kvm->users_count)); +} + +static int kvm_enable_virtualization(void); +static void kvm_disable_virtualization(void); + +static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) +{ + struct kvm *kvm = kvm_arch_alloc_vm(); + struct kvm_memslots *slots; + int r, i, j; + + if (!kvm) + return ERR_PTR(-ENOMEM); + + KVM_MMU_LOCK_INIT(kvm); + mmgrab(current->mm); + kvm->mm = current->mm; + kvm_eventfd_init(kvm); + mutex_init(&kvm->lock); + mutex_init(&kvm->irq_lock); + mutex_init(&kvm->slots_lock); + mutex_init(&kvm->slots_arch_lock); + spin_lock_init(&kvm->mn_invalidate_lock); + rcuwait_init(&kvm->mn_memslots_update_rcuwait); + xa_init(&kvm->vcpu_array); +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + xa_init(&kvm->mem_attr_array); +#endif + + INIT_LIST_HEAD(&kvm->gpc_list); + spin_lock_init(&kvm->gpc_lock); + + INIT_LIST_HEAD(&kvm->devices); + kvm->max_vcpus = KVM_MAX_VCPUS; + + BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX); + + /* + * Force subsequent debugfs file creations to fail if the VM directory + * is not created (by kvm_create_vm_debugfs()). + */ + kvm->debugfs_dentry = ERR_PTR(-ENOENT); + + snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d", + task_pid_nr(current)); + + r = -ENOMEM; + if (init_srcu_struct(&kvm->srcu)) + goto out_err_no_srcu; + if (init_srcu_struct(&kvm->irq_srcu)) + goto out_err_no_irq_srcu; + + r = kvm_init_irq_routing(kvm); + if (r) + goto out_err_no_irq_routing; + + refcount_set(&kvm->users_count, 1); + + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { + for (j = 0; j < 2; j++) { + slots = &kvm->__memslots[i][j]; + + atomic_long_set(&slots->last_used_slot, (unsigned long)NULL); + slots->hva_tree = RB_ROOT_CACHED; + slots->gfn_tree = RB_ROOT; + hash_init(slots->id_hash); + slots->node_idx = j; + + /* Generations must be different for each address space. */ + slots->generation = i; + } + + rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]); + } + + r = -ENOMEM; + for (i = 0; i < KVM_NR_BUSES; i++) { + rcu_assign_pointer(kvm->buses[i], + kzalloc_obj(struct kvm_io_bus, GFP_KERNEL_ACCOUNT)); + if (!kvm->buses[i]) + goto out_err_no_arch_destroy_vm; + } + + r = kvm_arch_init_vm(kvm, type); + if (r) + goto out_err_no_arch_destroy_vm; + + r = kvm_enable_virtualization(); + if (r) + goto out_err_no_disable; + +#ifdef CONFIG_HAVE_KVM_IRQCHIP + INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list); +#endif + + r = kvm_init_mmu_notifier(kvm); + if (r) + goto out_err_no_mmu_notifier; + + r = kvm_coalesced_mmio_init(kvm); + if (r < 0) + goto out_no_coalesced_mmio; + + r = kvm_create_vm_debugfs(kvm, fdname); + if (r) + goto out_err_no_debugfs; + + mutex_lock(&kvm_lock); + list_add(&kvm->vm_list, &vm_list); + mutex_unlock(&kvm_lock); + + preempt_notifier_inc(); + kvm_init_pm_notifier(kvm); + + return kvm; + +out_err_no_debugfs: + kvm_coalesced_mmio_free(kvm); +out_no_coalesced_mmio: + if (kvm->mmu_notifier.ops) + mmu_notifier_unregister(&kvm->mmu_notifier, current->mm); +out_err_no_mmu_notifier: + kvm_disable_virtualization(); +out_err_no_disable: + kvm_arch_destroy_vm(kvm); +out_err_no_arch_destroy_vm: + WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); + for (i = 0; i < KVM_NR_BUSES; i++) + kfree(kvm_get_bus_for_destruction(kvm, i)); + kvm_free_irq_routing(kvm); +out_err_no_irq_routing: + cleanup_srcu_struct(&kvm->irq_srcu); +out_err_no_irq_srcu: + cleanup_srcu_struct(&kvm->srcu); +out_err_no_srcu: + kvm_arch_free_vm(kvm); + mmdrop(current->mm); + return ERR_PTR(r); +} + +static void kvm_destroy_devices(struct kvm *kvm) +{ + struct kvm_device *dev, *tmp; + + /* + * We do not need to take the kvm->lock here, because nobody else + * has a reference to the struct kvm at this point and therefore + * cannot access the devices list anyhow. + * + * The device list is generally managed as an rculist, but list_del() + * is used intentionally here. If a bug in KVM introduced a reader that + * was not backed by a reference on the kvm struct, the hope is that + * it'd consume the poisoned forward pointer instead of suffering a + * use-after-free, even though this cannot be guaranteed. + */ + list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) { + list_del(&dev->vm_node); + dev->ops->destroy(dev); + } +} + +static void kvm_destroy_vm(struct kvm *kvm) +{ + int i; + struct mm_struct *mm = kvm->mm; + + kvm_destroy_pm_notifier(kvm); + kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm); + kvm_destroy_vm_debugfs(kvm); + mutex_lock(&kvm_lock); + list_del(&kvm->vm_list); + mutex_unlock(&kvm_lock); + kvm_arch_pre_destroy_vm(kvm); + + kvm_free_irq_routing(kvm); + for (i = 0; i < KVM_NR_BUSES; i++) { + struct kvm_io_bus *bus = kvm_get_bus_for_destruction(kvm, i); + + if (bus) + kvm_io_bus_destroy(bus); + kvm->buses[i] = NULL; + } + kvm_coalesced_mmio_free(kvm); + mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm); + /* + * At this point, pending calls to invalidate_range_start() + * have completed but no more MMU notifiers will run, so + * mn_active_invalidate_count may remain unbalanced. + * No threads can be waiting in kvm_swap_active_memslots() as the + * last reference on KVM has been dropped, but freeing + * memslots would deadlock without this manual intervention. + * + * If the count isn't unbalanced, i.e. KVM did NOT unregister its MMU + * notifier between a start() and end(), then there shouldn't be any + * in-progress invalidations. + */ + WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait)); + if (kvm->mn_active_invalidate_count) + kvm->mn_active_invalidate_count = 0; + else + WARN_ON(kvm->mmu_invalidate_in_progress); + kvm_arch_destroy_vm(kvm); + kvm_destroy_devices(kvm); + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { + kvm_free_memslots(kvm, &kvm->__memslots[i][0]); + kvm_free_memslots(kvm, &kvm->__memslots[i][1]); + } + cleanup_srcu_struct(&kvm->irq_srcu); + srcu_barrier(&kvm->srcu); + cleanup_srcu_struct(&kvm->srcu); +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + xa_destroy(&kvm->mem_attr_array); +#endif + kvm_arch_free_vm(kvm); + preempt_notifier_dec(); + kvm_disable_virtualization(); + mmdrop(mm); +} + +void kvm_get_kvm(struct kvm *kvm) +{ + refcount_inc(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm); + +/* + * Make sure the vm is not during destruction, which is a safe version of + * kvm_get_kvm(). Return true if kvm referenced successfully, false otherwise. + */ +bool kvm_get_kvm_safe(struct kvm *kvm) +{ + return refcount_inc_not_zero(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm_safe); + +void kvm_put_kvm(struct kvm *kvm) +{ + if (refcount_dec_and_test(&kvm->users_count)) + kvm_destroy_vm(kvm); +} +EXPORT_SYMBOL_GPL(kvm_put_kvm); + +/* + * Used to put a reference that was taken on behalf of an object associated + * with a user-visible file descriptor, e.g. a vcpu or device, if installation + * of the new file descriptor fails and the reference cannot be transferred to + * its final owner. In such cases, the caller is still actively using @kvm and + * will fail miserably if the refcount unexpectedly hits zero. + */ +void kvm_put_kvm_no_destroy(struct kvm *kvm) +{ + WARN_ON(refcount_dec_and_test(&kvm->users_count)); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_put_kvm_no_destroy); + +static int kvm_vm_release(struct inode *inode, struct file *filp) +{ + struct kvm *kvm = filp->private_data; + + kvm_irqfd_release(kvm); + + kvm_put_kvm(kvm); + return 0; +} + +int kvm_trylock_all_vcpus(struct kvm *kvm) +{ + struct kvm_vcpu *vcpu; + unsigned long i, j; + + lockdep_assert_held(&kvm->lock); + + kvm_for_each_vcpu(i, vcpu, kvm) + if (!mutex_trylock_nest_lock(&vcpu->mutex, &kvm->lock)) + goto out_unlock; + return 0; + +out_unlock: + kvm_for_each_vcpu(j, vcpu, kvm) { + if (i == j) + break; + mutex_unlock(&vcpu->mutex); + } + return -EINTR; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_trylock_all_vcpus); + +int kvm_lock_all_vcpus(struct kvm *kvm) +{ + struct kvm_vcpu *vcpu; + unsigned long i, j; + int r; + + lockdep_assert_held(&kvm->lock); + + kvm_for_each_vcpu(i, vcpu, kvm) { + r = mutex_lock_killable_nest_lock(&vcpu->mutex, &kvm->lock); + if (r) + goto out_unlock; + } + return 0; + +out_unlock: + kvm_for_each_vcpu(j, vcpu, kvm) { + if (i == j) + break; + mutex_unlock(&vcpu->mutex); + } + return r; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lock_all_vcpus); + +void kvm_unlock_all_vcpus(struct kvm *kvm) +{ + struct kvm_vcpu *vcpu; + unsigned long i; + + lockdep_assert_held(&kvm->lock); + + kvm_for_each_vcpu(i, vcpu, kvm) + mutex_unlock(&vcpu->mutex); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_unlock_all_vcpus); + +/* + * Allocation size is twice as large as the actual dirty bitmap size. + * See kvm_vm_ioctl_get_dirty_log() why this is needed. + */ +static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot) +{ + unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot); + + memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT); + if (!memslot->dirty_bitmap) + return -ENOMEM; + + return 0; +} + +static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id) +{ + struct kvm_memslots *active = __kvm_memslots(kvm, as_id); + int node_idx_inactive = active->node_idx ^ 1; + + return &kvm->__memslots[as_id][node_idx_inactive]; +} + +/* + * Helper to get the address space ID when one of memslot pointers may be NULL. + * This also serves as a sanity that at least one of the pointers is non-NULL, + * and that their address space IDs don't diverge. + */ +static int kvm_memslots_get_as_id(struct kvm_memory_slot *a, + struct kvm_memory_slot *b) +{ + if (WARN_ON_ONCE(!a && !b)) + return 0; + + if (!a) + return b->as_id; + if (!b) + return a->as_id; + + WARN_ON_ONCE(a->as_id != b->as_id); + return a->as_id; +} + +static void kvm_insert_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *slot) +{ + struct rb_root *gfn_tree = &slots->gfn_tree; + struct rb_node **node, *parent; + int idx = slots->node_idx; + + parent = NULL; + for (node = &gfn_tree->rb_node; *node; ) { + struct kvm_memory_slot *tmp; + + tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]); + parent = *node; + if (slot->base_gfn < tmp->base_gfn) + node = &(*node)->rb_left; + else if (slot->base_gfn > tmp->base_gfn) + node = &(*node)->rb_right; + else + BUG(); + } + + rb_link_node(&slot->gfn_node[idx], parent, node); + rb_insert_color(&slot->gfn_node[idx], gfn_tree); +} + +static void kvm_erase_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *slot) +{ + rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree); +} + +static void kvm_replace_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int idx = slots->node_idx; + + WARN_ON_ONCE(old->base_gfn != new->base_gfn); + + rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx], + &slots->gfn_tree); +} + +/* + * Replace @old with @new in the inactive memslots. + * + * With NULL @old this simply adds @new. + * With NULL @new this simply removes @old. + * + * If @new is non-NULL its hva_node[slots_idx] range has to be set + * appropriately. + */ +static void kvm_replace_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int as_id = kvm_memslots_get_as_id(old, new); + struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id); + int idx = slots->node_idx; + + if (old) { + hash_del(&old->id_node[idx]); + interval_tree_remove(&old->hva_node[idx], &slots->hva_tree); + + if ((long)old == atomic_long_read(&slots->last_used_slot)) + atomic_long_set(&slots->last_used_slot, (long)new); + + if (!new) { + kvm_erase_gfn_node(slots, old); + return; + } + } + + /* + * Initialize @new's hva range. Do this even when replacing an @old + * slot, kvm_copy_memslot() deliberately does not touch node data. + */ + new->hva_node[idx].start = new->userspace_addr; + new->hva_node[idx].last = new->userspace_addr + + (new->npages << PAGE_SHIFT) - 1; + + /* + * (Re)Add the new memslot. There is no O(1) interval_tree_replace(), + * hva_node needs to be swapped with remove+insert even though hva can't + * change when replacing an existing slot. + */ + hash_add(slots->id_hash, &new->id_node[idx], new->id); + interval_tree_insert(&new->hva_node[idx], &slots->hva_tree); + + /* + * If the memslot gfn is unchanged, rb_replace_node() can be used to + * switch the node in the gfn tree instead of removing the old and + * inserting the new as two separate operations. Replacement is a + * single O(1) operation versus two O(log(n)) operations for + * remove+insert. + */ + if (old && old->base_gfn == new->base_gfn) { + kvm_replace_gfn_node(slots, old, new); + } else { + if (old) + kvm_erase_gfn_node(slots, old); + kvm_insert_gfn_node(slots, new); + } +} + +/* + * Flags that do not access any of the extra space of struct + * kvm_userspace_memory_region2. KVM_SET_USER_MEMORY_REGION_V1_FLAGS + * only allows these. + */ +#define KVM_SET_USER_MEMORY_REGION_V1_FLAGS \ + (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY) + +static int check_memory_region_flags(struct kvm *kvm, + const struct kvm_userspace_memory_region2 *mem) +{ + u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; + + if (IS_ENABLED(CONFIG_KVM_GUEST_MEMFD)) + valid_flags |= KVM_MEM_GUEST_MEMFD; + + /* Dirty logging private memory is not currently supported. */ + if (mem->flags & KVM_MEM_GUEST_MEMFD) + valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES; + + /* + * GUEST_MEMFD is incompatible with read-only memslots, as writes to + * read-only memslots have emulated MMIO, not page fault, semantics, + * and KVM doesn't allow emulated MMIO for private memory. + */ + if (kvm_arch_has_readonly_mem(kvm) && + !(mem->flags & KVM_MEM_GUEST_MEMFD)) + valid_flags |= KVM_MEM_READONLY; + + if (mem->flags & ~valid_flags) + return -EINVAL; + + return 0; +} + +static void kvm_swap_active_memslots(struct kvm *kvm, int as_id) +{ + struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id); + + /* Grab the generation from the activate memslots. */ + u64 gen = __kvm_memslots(kvm, as_id)->generation; + + WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS); + slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS; + + /* + * Do not store the new memslots while there are invalidations in + * progress, otherwise the locking in invalidate_range_start and + * invalidate_range_end will be unbalanced. + */ + spin_lock(&kvm->mn_invalidate_lock); + prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait); + while (kvm->mn_active_invalidate_count) { + set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock(&kvm->mn_invalidate_lock); + schedule(); + spin_lock(&kvm->mn_invalidate_lock); + } + finish_rcuwait(&kvm->mn_memslots_update_rcuwait); + rcu_assign_pointer(kvm->memslots[as_id], slots); + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * Acquired in kvm_set_memslot. Must be released before synchronize + * SRCU below in order to avoid deadlock with another thread + * acquiring the slots_arch_lock in an srcu critical section. + */ + mutex_unlock(&kvm->slots_arch_lock); + + synchronize_srcu_expedited(&kvm->srcu); + + /* + * Increment the new memslot generation a second time, dropping the + * update in-progress flag and incrementing the generation based on + * the number of address spaces. This provides a unique and easily + * identifiable generation number while the memslots are in flux. + */ + gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS; + + /* + * Generations must be unique even across address spaces. We do not need + * a global counter for that, instead the generation space is evenly split + * across address spaces. For example, with two address spaces, address + * space 0 will use generations 0, 2, 4, ... while address space 1 will + * use generations 1, 3, 5, ... + */ + gen += kvm_arch_nr_memslot_as_ids(kvm); + + kvm_arch_memslots_updated(kvm, gen); + + slots->generation = gen; +} + +static int kvm_prepare_memory_region(struct kvm *kvm, + const struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + int r; + + /* + * If dirty logging is disabled, nullify the bitmap; the old bitmap + * will be freed on "commit". If logging is enabled in both old and + * new, reuse the existing bitmap. If logging is enabled only in the + * new and KVM isn't using a ring buffer, allocate and initialize a + * new bitmap. + */ + if (change != KVM_MR_DELETE) { + if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) + new->dirty_bitmap = NULL; + else if (old && old->dirty_bitmap) + new->dirty_bitmap = old->dirty_bitmap; + else if (kvm_use_dirty_bitmap(kvm)) { + r = kvm_alloc_dirty_bitmap(new); + if (r) + return r; + + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) + bitmap_set(new->dirty_bitmap, 0, new->npages); + } + } + + r = kvm_arch_prepare_memory_region(kvm, old, new, change); + + /* Free the bitmap on failure if it was allocated above. */ + if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap)) + kvm_destroy_dirty_bitmap(new); + + return r; +} + +static void kvm_commit_memory_region(struct kvm *kvm, + struct kvm_memory_slot *old, + const struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + int old_flags = old ? old->flags : 0; + int new_flags = new ? new->flags : 0; + /* + * Update the total number of memslot pages before calling the arch + * hook so that architectures can consume the result directly. + */ + if (change == KVM_MR_DELETE) + kvm->nr_memslot_pages -= old->npages; + else if (change == KVM_MR_CREATE) + kvm->nr_memslot_pages += new->npages; + + if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) { + int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1; + atomic_set(&kvm->nr_memslots_dirty_logging, + atomic_read(&kvm->nr_memslots_dirty_logging) + change); + } + + kvm_arch_commit_memory_region(kvm, old, new, change); + + switch (change) { + case KVM_MR_CREATE: + /* Nothing more to do. */ + break; + case KVM_MR_DELETE: + /* Free the old memslot and all its metadata. */ + kvm_free_memslot(kvm, old); + break; + case KVM_MR_MOVE: + /* + * Moving a guest_memfd memslot isn't supported, and will never + * be supported. + */ + WARN_ON_ONCE(old->flags & KVM_MEM_GUEST_MEMFD); + fallthrough; + case KVM_MR_FLAGS_ONLY: + /* + * Free the dirty bitmap as needed; the below check encompasses + * both the flags and whether a ring buffer is being used) + */ + if (old->dirty_bitmap && !new->dirty_bitmap) + kvm_destroy_dirty_bitmap(old); + + /* + * Unbind the guest_memfd instance as needed; the @new slot has + * already created its own binding. TODO: Drop the WARN when + * dirty logging guest_memfd memslots is supported. Until then, + * flags-only changes on guest_memfd slots should be impossible. + */ + if (WARN_ON_ONCE(old->flags & KVM_MEM_GUEST_MEMFD)) + kvm_gmem_unbind(old); + + /* + * The final quirk. Free the detached, old slot, but only its + * memory, not any metadata. Metadata, including arch specific + * data, may be reused by @new. + */ + kfree(old); + break; + default: + BUG(); + } +} + +/* + * Activate @new, which must be installed in the inactive slots by the caller, + * by swapping the active slots and then propagating @new to @old once @old is + * unreachable and can be safely modified. + * + * With NULL @old this simply adds @new to @active (while swapping the sets). + * With NULL @new this simply removes @old from @active and frees it + * (while also swapping the sets). + */ +static void kvm_activate_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int as_id = kvm_memslots_get_as_id(old, new); + + kvm_swap_active_memslots(kvm, as_id); + + /* Propagate the new memslot to the now inactive memslots. */ + kvm_replace_memslot(kvm, old, new); +} + +static void kvm_copy_memslot(struct kvm_memory_slot *dest, + const struct kvm_memory_slot *src) +{ + dest->base_gfn = src->base_gfn; + dest->npages = src->npages; + dest->dirty_bitmap = src->dirty_bitmap; + dest->arch = src->arch; + dest->userspace_addr = src->userspace_addr; + dest->flags = src->flags; + dest->id = src->id; + dest->as_id = src->as_id; +} + +static void kvm_invalidate_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Mark the current slot INVALID. As with all memslot modifications, + * this must be done on an unreachable slot to avoid modifying the + * current slot in the active tree. + */ + kvm_copy_memslot(invalid_slot, old); + invalid_slot->flags |= KVM_MEMSLOT_INVALID; + kvm_replace_memslot(kvm, old, invalid_slot); + + /* + * Activate the slot that is now marked INVALID, but don't propagate + * the slot to the now inactive slots. The slot is either going to be + * deleted or recreated as a new slot. + */ + kvm_swap_active_memslots(kvm, old->as_id); + + /* + * From this point no new shadow pages pointing to a deleted, or moved, + * memslot will be created. Validation of sp->gfn happens in: + * - gfn_to_hva (kvm_read_guest, gfn_to_pfn) + * - kvm_is_visible_gfn (mmu_check_root) + */ + kvm_arch_flush_shadow_memslot(kvm, old); + kvm_arch_guest_memory_reclaimed(kvm); + + /* Was released by kvm_swap_active_memslots(), reacquire. */ + mutex_lock(&kvm->slots_arch_lock); + + /* + * Copy the arch-specific field of the newly-installed slot back to the + * old slot as the arch data could have changed between releasing + * slots_arch_lock in kvm_swap_active_memslots() and re-acquiring the lock + * above. Writers are required to retrieve memslots *after* acquiring + * slots_arch_lock, thus the active slot's data is guaranteed to be fresh. + */ + old->arch = invalid_slot->arch; +} + +static void kvm_create_memslot(struct kvm *kvm, + struct kvm_memory_slot *new) +{ + /* Add the new memslot to the inactive set and activate. */ + kvm_replace_memslot(kvm, NULL, new); + kvm_activate_memslot(kvm, NULL, new); +} + +static void kvm_delete_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Remove the old memslot (in the inactive memslots) by passing NULL as + * the "new" slot, and for the invalid version in the active slots. + */ + kvm_replace_memslot(kvm, old, NULL); + kvm_activate_memslot(kvm, invalid_slot, NULL); +} + +static void kvm_move_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Replace the old memslot in the inactive slots, and then swap slots + * and replace the current INVALID with the new as well. + */ + kvm_replace_memslot(kvm, old, new); + kvm_activate_memslot(kvm, invalid_slot, new); +} + +static void kvm_update_flags_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + /* + * Similar to the MOVE case, but the slot doesn't need to be zapped as + * an intermediate step. Instead, the old memslot is simply replaced + * with a new, updated copy in both memslot sets. + */ + kvm_replace_memslot(kvm, old, new); + kvm_activate_memslot(kvm, old, new); +} + +static int kvm_set_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + struct kvm_memory_slot *invalid_slot; + int r; + + /* + * Released in kvm_swap_active_memslots(). + * + * Must be held from before the current memslots are copied until after + * the new memslots are installed with rcu_assign_pointer, then + * released before the synchronize srcu in kvm_swap_active_memslots(). + * + * When modifying memslots outside of the slots_lock, must be held + * before reading the pointer to the current memslots until after all + * changes to those memslots are complete. + * + * These rules ensure that installing new memslots does not lose + * changes made to the previous memslots. + */ + mutex_lock(&kvm->slots_arch_lock); + + /* + * Invalidate the old slot if it's being deleted or moved. This is + * done prior to actually deleting/moving the memslot to allow vCPUs to + * continue running by ensuring there are no mappings or shadow pages + * for the memslot when it is deleted/moved. Without pre-invalidation + * (and without a lock), a window would exist between effecting the + * delete/move and committing the changes in arch code where KVM or a + * guest could access a non-existent memslot. + * + * Modifications are done on a temporary, unreachable slot. The old + * slot needs to be preserved in case a later step fails and the + * invalidation needs to be reverted. + */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) { + invalid_slot = kzalloc_obj(*invalid_slot, GFP_KERNEL_ACCOUNT); + if (!invalid_slot) { + mutex_unlock(&kvm->slots_arch_lock); + return -ENOMEM; + } + kvm_invalidate_memslot(kvm, old, invalid_slot); + } + + r = kvm_prepare_memory_region(kvm, old, new, change); + if (r) { + /* + * For DELETE/MOVE, revert the above INVALID change. No + * modifications required since the original slot was preserved + * in the inactive slots. Changing the active memslots also + * release slots_arch_lock. + */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) { + kvm_activate_memslot(kvm, invalid_slot, old); + kfree(invalid_slot); + } else { + mutex_unlock(&kvm->slots_arch_lock); + } + return r; + } + + /* + * For DELETE and MOVE, the working slot is now active as the INVALID + * version of the old slot. MOVE is particularly special as it reuses + * the old slot and returns a copy of the old slot (in working_slot). + * For CREATE, there is no old slot. For DELETE and FLAGS_ONLY, the + * old slot is detached but otherwise preserved. + */ + if (change == KVM_MR_CREATE) + kvm_create_memslot(kvm, new); + else if (change == KVM_MR_DELETE) + kvm_delete_memslot(kvm, old, invalid_slot); + else if (change == KVM_MR_MOVE) + kvm_move_memslot(kvm, old, new, invalid_slot); + else if (change == KVM_MR_FLAGS_ONLY) + kvm_update_flags_memslot(kvm, old, new); + else + BUG(); + + /* Free the temporary INVALID slot used for DELETE and MOVE. */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) + kfree(invalid_slot); + + /* + * No need to refresh new->arch, changes after dropping slots_arch_lock + * will directly hit the final, active memslot. Architectures are + * responsible for knowing that new->arch may be stale. + */ + kvm_commit_memory_region(kvm, old, new, change); + + return 0; +} + +static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, + gfn_t start, gfn_t end) +{ + struct kvm_memslot_iter iter; + + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { + if (iter.slot->id != id) + return true; + } + + return false; +} + +static int kvm_set_memory_region(struct kvm *kvm, + const struct kvm_userspace_memory_region2 *mem) +{ + struct kvm_memory_slot *old, *new; + struct kvm_memslots *slots; + enum kvm_mr_change change; + unsigned long npages; + gfn_t base_gfn; + int as_id, id; + int r; + + lockdep_assert_held(&kvm->slots_lock); + + r = check_memory_region_flags(kvm, mem); + if (r) + return r; + + as_id = mem->slot >> 16; + id = (u16)mem->slot; + + /* General sanity checks */ + if ((mem->memory_size & (PAGE_SIZE - 1)) || + (mem->memory_size != (unsigned long)mem->memory_size)) + return -EINVAL; + if (mem->guest_phys_addr & (PAGE_SIZE - 1)) + return -EINVAL; + /* We can read the guest memory with __xxx_user() later on. */ + if ((mem->userspace_addr & (PAGE_SIZE - 1)) || + (mem->userspace_addr != untagged_addr(mem->userspace_addr)) || + !access_ok((void __user *)(unsigned long)mem->userspace_addr, + mem->memory_size)) + return -EINVAL; + if (mem->flags & KVM_MEM_GUEST_MEMFD && + (mem->guest_memfd_offset & (PAGE_SIZE - 1) || + mem->guest_memfd_offset + mem->memory_size < mem->guest_memfd_offset)) + return -EINVAL; + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM) + return -EINVAL; + if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) + return -EINVAL; + + /* + * The size of userspace-defined memory regions is restricted in order + * to play nice with dirty bitmap operations, which are indexed with an + * "unsigned int". KVM's internal memory regions don't support dirty + * logging, and so are exempt. + */ + if (id < KVM_USER_MEM_SLOTS && + (mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + + /* + * Note, the old memslot (and the pointer itself!) may be invalidated + * and/or destroyed by kvm_set_memslot(). + */ + old = id_to_memslot(slots, id); + + if (!mem->memory_size) { + if (!old || !old->npages) + return -EINVAL; + + if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages)) + return -EIO; + + return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE); + } + + base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT); + npages = (mem->memory_size >> PAGE_SHIFT); + + if (!old || !old->npages) { + change = KVM_MR_CREATE; + + /* + * To simplify KVM internals, the total number of pages across + * all memslots must fit in an unsigned long. + */ + if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) + return -EINVAL; + } else { /* Modify an existing slot. */ + /* Private memslots are immutable, they can only be deleted. */ + if (mem->flags & KVM_MEM_GUEST_MEMFD) + return -EINVAL; + if ((mem->userspace_addr != old->userspace_addr) || + (npages != old->npages) || + ((mem->flags ^ old->flags) & (KVM_MEM_READONLY | KVM_MEM_GUEST_MEMFD))) + return -EINVAL; + + if (base_gfn != old->base_gfn) + change = KVM_MR_MOVE; + else if (mem->flags != old->flags) + change = KVM_MR_FLAGS_ONLY; + else /* Nothing to change. */ + return 0; + } + + if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) && + kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages)) + return -EEXIST; + + /* Allocate a slot that will persist in the memslot. */ + new = kzalloc_obj(*new, GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->as_id = as_id; + new->id = id; + new->base_gfn = base_gfn; + new->npages = npages; + new->flags = mem->flags; + new->userspace_addr = mem->userspace_addr; + if (mem->flags & KVM_MEM_GUEST_MEMFD) { + r = kvm_gmem_bind(kvm, new, mem->guest_memfd, mem->guest_memfd_offset); + if (r) + goto out; + } + + r = kvm_set_memslot(kvm, old, new, change); + if (r) + goto out_unbind; + + return 0; + +out_unbind: + if (mem->flags & KVM_MEM_GUEST_MEMFD) + kvm_gmem_unbind(new); +out: + kfree(new); + return r; +} + +int kvm_set_internal_memslot(struct kvm *kvm, + const struct kvm_userspace_memory_region2 *mem) +{ + if (WARN_ON_ONCE(mem->slot < KVM_USER_MEM_SLOTS)) + return -EINVAL; + + if (WARN_ON_ONCE(mem->flags)) + return -EINVAL; + + return kvm_set_memory_region(kvm, mem); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_set_internal_memslot); + +static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, + struct kvm_userspace_memory_region2 *mem) +{ + if ((u16)mem->slot >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + guard(mutex)(&kvm->slots_lock); + return kvm_set_memory_region(kvm, mem); +} + +#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT +/** + * kvm_get_dirty_log - get a snapshot of dirty pages + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * @is_dirty: set to '1' if any dirty pages were found + * @memslot: set to the associated memslot, always valid on success + */ +int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, + int *is_dirty, struct kvm_memory_slot **memslot) +{ + struct kvm_memslots *slots; + int i, as_id, id; + unsigned long n; + unsigned long any = 0; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + *memslot = NULL; + *is_dirty = 0; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + *memslot = id_to_memslot(slots, id); + if (!(*memslot) || !(*memslot)->dirty_bitmap) + return -ENOENT; + + kvm_arch_sync_dirty_log(kvm, *memslot); + + n = kvm_dirty_bitmap_bytes(*memslot); + + for (i = 0; !any && i < n/sizeof(long); ++i) + any = (*memslot)->dirty_bitmap[i]; + + if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n)) + return -EFAULT; + + if (any) + *is_dirty = 1; + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_get_dirty_log); + +#else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ +/** + * kvm_get_dirty_log_protect - get a snapshot of dirty pages + * and reenable dirty page tracking for the corresponding pages. + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * + * We need to keep it in mind that VCPU threads can write to the bitmap + * concurrently. So, to avoid losing track of dirty pages we keep the + * following order: + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Upon return caller flushes TLB's if needed. + * + * Between 2 and 4, the guest may write to the page using the remaining TLB + * entry. This is not a problem because the page is reported dirty using + * the snapshot taken before and step 4 ensures that writes done after + * exiting to userspace will be logged for the next call. + * + */ +static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int i, as_id, id; + unsigned long n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + bool flush; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; + + dirty_bitmap = memslot->dirty_bitmap; + + kvm_arch_sync_dirty_log(kvm, memslot); + + n = kvm_dirty_bitmap_bytes(memslot); + flush = false; + if (kvm->manual_dirty_log_protect) { + /* + * Unlike kvm_get_dirty_log, we always return false in *flush, + * because no flush is needed until KVM_CLEAR_DIRTY_LOG. There + * is some code duplication between this function and + * kvm_get_dirty_log, but hopefully all architecture + * transition to kvm_get_dirty_log_protect and kvm_get_dirty_log + * can be eliminated. + */ + dirty_bitmap_buffer = dirty_bitmap; + } else { + dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot); + memset(dirty_bitmap_buffer, 0, n); + + KVM_MMU_LOCK(kvm); + for (i = 0; i < n / sizeof(long); i++) { + unsigned long mask; + gfn_t offset; + + if (!dirty_bitmap[i]) + continue; + + flush = true; + mask = xchg(&dirty_bitmap[i], 0); + dirty_bitmap_buffer[i] = mask; + + offset = i * BITS_PER_LONG; + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, + offset, mask); + } + KVM_MMU_UNLOCK(kvm); + } + + if (flush) + kvm_flush_remote_tlbs_memslot(kvm, memslot); + + if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n)) + return -EFAULT; + return 0; +} + + +/** + * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot + * @kvm: kvm instance + * @log: slot id and address to which we copy the log + * + * Steps 1-4 below provide general overview of dirty page logging. See + * kvm_get_dirty_log_protect() function description for additional details. + * + * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we + * always flush the TLB (step 4) even if previous step failed and the dirty + * bitmap may be corrupt. Regardless of previous outcome the KVM logging API + * does not preclude user space subsequent dirty log read. Flushing TLB ensures + * writes will be marked dirty for next log read. + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Flush TLB's if needed. + */ +static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, + struct kvm_dirty_log *log) +{ + int r; + + mutex_lock(&kvm->slots_lock); + + r = kvm_get_dirty_log_protect(kvm, log); + + mutex_unlock(&kvm->slots_lock); + return r; +} + +/** + * kvm_clear_dirty_log_protect - clear dirty bits in the bitmap + * and reenable dirty page tracking for the corresponding pages. + * @kvm: pointer to kvm instance + * @log: slot id and address from which to fetch the bitmap of dirty pages + */ +static int kvm_clear_dirty_log_protect(struct kvm *kvm, + struct kvm_clear_dirty_log *log) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int as_id, id; + gfn_t offset; + unsigned long i, n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + bool flush; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + if (log->first_page & 63) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; + + dirty_bitmap = memslot->dirty_bitmap; + + n = ALIGN(log->num_pages, BITS_PER_LONG) / 8; + + if (log->first_page > memslot->npages || + log->num_pages > memslot->npages - log->first_page || + (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63))) + return -EINVAL; + + kvm_arch_sync_dirty_log(kvm, memslot); + + flush = false; + dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot); + if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n)) + return -EFAULT; + + KVM_MMU_LOCK(kvm); + for (offset = log->first_page, i = offset / BITS_PER_LONG, + n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--; + i++, offset += BITS_PER_LONG) { + unsigned long mask = *dirty_bitmap_buffer++; + atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i]; + if (!mask) + continue; + + mask &= atomic_long_fetch_andnot(mask, p); + + /* + * mask contains the bits that really have been cleared. This + * never includes any bits beyond the length of the memslot (if + * the length is not aligned to 64 pages), therefore it is not + * a problem if userspace sets them in log->dirty_bitmap. + */ + if (mask) { + flush = true; + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, + offset, mask); + } + } + KVM_MMU_UNLOCK(kvm); + + if (flush) + kvm_flush_remote_tlbs_memslot(kvm, memslot); + + return 0; +} + +static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, + struct kvm_clear_dirty_log *log) +{ + int r; + + mutex_lock(&kvm->slots_lock); + + r = kvm_clear_dirty_log_protect(kvm, log); + + mutex_unlock(&kvm->slots_lock); + return r; +} +#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ + +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +static u64 kvm_supported_mem_attributes(struct kvm *kvm) +{ + if (!kvm || kvm_arch_has_private_mem(kvm)) + return KVM_MEMORY_ATTRIBUTE_PRIVATE; + + return 0; +} + +/* + * Returns true if _all_ gfns in the range [@start, @end) have attributes + * such that the bits in @mask match @attrs. + */ +bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long mask, unsigned long attrs) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + unsigned long index; + void *entry; + + mask &= kvm_supported_mem_attributes(kvm); + if (attrs & ~mask) + return false; + + if (end == start + 1) + return (kvm_get_memory_attributes(kvm, start) & mask) == attrs; + + guard(rcu)(); + if (!attrs) + return !xas_find(&xas, end - 1); + + for (index = start; index < end; index++) { + do { + entry = xas_next(&xas); + } while (xas_retry(&xas, entry)); + + if (xas.xa_index != index || + (xa_to_value(entry) & mask) != attrs) + return false; + } + + return true; +} + +static __always_inline void kvm_handle_gfn_range(struct kvm *kvm, + struct kvm_mmu_notifier_range *range) +{ + struct kvm_gfn_range gfn_range; + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + struct kvm_memslot_iter iter; + bool found_memslot = false; + bool ret = false; + int i; + + gfn_range.arg = range->arg; + gfn_range.may_block = range->may_block; + + /* + * If/when KVM supports more attributes beyond private .vs shared, this + * _could_ set KVM_FILTER_{SHARED,PRIVATE} appropriately if the entire target + * range already has the desired private vs. shared state (it's unclear + * if that is a net win). For now, KVM reaches this point if and only + * if the private flag is being toggled, i.e. all mappings are in play. + */ + + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { + slots = __kvm_memslots(kvm, i); + + kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) { + slot = iter.slot; + gfn_range.slot = slot; + + gfn_range.start = max(range->start, slot->base_gfn); + gfn_range.end = min(range->end, slot->base_gfn + slot->npages); + if (gfn_range.start >= gfn_range.end) + continue; + + if (!found_memslot) { + found_memslot = true; + KVM_MMU_LOCK(kvm); + if (!IS_KVM_NULL_FN(range->on_lock)) + range->on_lock(kvm); + } + + ret |= range->handler(kvm, &gfn_range); + } + } + + if (range->flush_on_ret && ret) + kvm_flush_remote_tlbs(kvm); + + if (found_memslot) + KVM_MMU_UNLOCK(kvm); +} + +static bool kvm_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + /* + * Unconditionally add the range to the invalidation set, regardless of + * whether or not the arch callback actually needs to zap SPTEs. E.g. + * if KVM supports RWX attributes in the future and the attributes are + * going from R=>RW, zapping isn't strictly necessary. Unconditionally + * adding the range allows KVM to require that MMU invalidations add at + * least one range between begin() and end(), e.g. allows KVM to detect + * bugs where the add() is missed. Relaxing the rule *might* be safe, + * but it's not obvious that allowing new mappings while the attributes + * are in flux is desirable or worth the complexity. + */ + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); + + return kvm_arch_pre_set_memory_attributes(kvm, range); +} + +/* Set @attributes for the gfn range [@start, @end). */ +static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attributes) +{ + struct kvm_mmu_notifier_range pre_set_range = { + .start = start, + .end = end, + .arg.attributes = attributes, + .handler = kvm_pre_set_memory_attributes, + .on_lock = kvm_mmu_invalidate_start, + .flush_on_ret = true, + .may_block = true, + }; + struct kvm_mmu_notifier_range post_set_range = { + .start = start, + .end = end, + .arg.attributes = attributes, + .handler = kvm_arch_post_set_memory_attributes, + .on_lock = kvm_mmu_invalidate_end, + .may_block = true, + }; + unsigned long i; + void *entry; + int r = 0; + + entry = attributes ? xa_mk_value(attributes) : NULL; + + trace_kvm_vm_set_mem_attributes(start, end, attributes); + + mutex_lock(&kvm->slots_lock); + + /* Nothing to do if the entire range has the desired attributes. */ + if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes)) + goto out_unlock; + + /* + * Reserve memory ahead of time to avoid having to deal with failures + * partway through setting the new attributes. + */ + for (i = start; i < end; i++) { + r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT); + if (r) + goto out_unlock; + + cond_resched(); + } + + kvm_handle_gfn_range(kvm, &pre_set_range); + + for (i = start; i < end; i++) { + r = xa_err(xa_store(&kvm->mem_attr_array, i, entry, + GFP_KERNEL_ACCOUNT)); + KVM_BUG_ON(r, kvm); + cond_resched(); + } + + kvm_handle_gfn_range(kvm, &post_set_range); + +out_unlock: + mutex_unlock(&kvm->slots_lock); + + return r; +} +static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, + struct kvm_memory_attributes *attrs) +{ + gfn_t start, end; + + /* flags is currently not used. */ + if (attrs->flags) + return -EINVAL; + if (attrs->attributes & ~kvm_supported_mem_attributes(kvm)) + return -EINVAL; + if (attrs->size == 0 || attrs->address + attrs->size < attrs->address) + return -EINVAL; + if (!PAGE_ALIGNED(attrs->address) || !PAGE_ALIGNED(attrs->size)) + return -EINVAL; + + start = attrs->address >> PAGE_SHIFT; + end = (attrs->address + attrs->size) >> PAGE_SHIFT; + + /* + * xarray tracks data using "unsigned long", and as a result so does + * KVM. For simplicity, supports generic attributes only on 64-bit + * architectures. + */ + BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long)); + + return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes); +} +#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ + +struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn) +{ + return __gfn_to_memslot(kvm_memslots(kvm), gfn); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(gfn_to_memslot); + +struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu); + u64 gen = slots->generation; + struct kvm_memory_slot *slot; + + /* + * This also protects against using a memslot from a different address space, + * since different address spaces have different generation numbers. + */ + if (unlikely(gen != vcpu->last_used_slot_gen)) { + vcpu->last_used_slot = NULL; + vcpu->last_used_slot_gen = gen; + } + + slot = try_get_memslot(vcpu->last_used_slot, gfn); + if (slot) + return slot; + + /* + * Fall back to searching all memslots. We purposely use + * search_memslots() instead of __gfn_to_memslot() to avoid + * thrashing the VM-wide last_used_slot in kvm_memslots. + */ + slot = search_memslots(slots, gfn, false); + if (slot) { + vcpu->last_used_slot = slot; + return slot; + } + + return NULL; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_gfn_to_memslot); + +bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) +{ + struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn); + + return kvm_is_visible_memslot(memslot); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_is_visible_gfn); + +bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return kvm_is_visible_memslot(memslot); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_is_visible_gfn); + +unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct vm_area_struct *vma; + unsigned long addr, size; + + size = PAGE_SIZE; + + addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL); + if (kvm_is_error_hva(addr)) + return PAGE_SIZE; + + mmap_read_lock(current->mm); + vma = find_vma(current->mm, addr); + if (!vma) + goto out; + + size = vma_kernel_pagesize(vma); + +out: + mmap_read_unlock(current->mm); + + return size; +} + +static bool memslot_is_readonly(const struct kvm_memory_slot *slot) +{ + return slot->flags & KVM_MEM_READONLY; +} + +static unsigned long __gfn_to_hva_many(const struct kvm_memory_slot *slot, gfn_t gfn, + gfn_t *nr_pages, bool write) +{ + if (!slot || slot->flags & KVM_MEMSLOT_INVALID) + return KVM_HVA_ERR_BAD; + + if (memslot_is_readonly(slot) && write) + return KVM_HVA_ERR_RO_BAD; + + if (nr_pages) + *nr_pages = slot->npages - (gfn - slot->base_gfn); + + return __gfn_to_hva_memslot(slot, gfn); +} + +static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn, + gfn_t *nr_pages) +{ + return __gfn_to_hva_many(slot, gfn, nr_pages, true); +} + +unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, + gfn_t gfn) +{ + return gfn_to_hva_many(slot, gfn, NULL); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(gfn_to_hva_memslot); + +unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) +{ + return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(gfn_to_hva); + +unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_gfn_to_hva); + +/* + * Return the hva of a @gfn and the R/W attribute if possible. + * + * @slot: the kvm_memory_slot which contains @gfn + * @gfn: the gfn to be translated + * @writable: used to return the read/write attribute of the @slot if the hva + * is valid and @writable is not NULL + */ +unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot, + gfn_t gfn, bool *writable) +{ + unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false); + + if (!kvm_is_error_hva(hva) && writable) + *writable = !memslot_is_readonly(slot); + + return hva; +} + +unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return gfn_to_hva_memslot_prot(slot, gfn, writable); +} + +unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return gfn_to_hva_memslot_prot(slot, gfn, writable); +} + +static bool kvm_is_ad_tracked_page(struct page *page) +{ + /* + * Per page-flags.h, pages tagged PG_reserved "should in general not be + * touched (e.g. set dirty) except by its owner". + */ + return !PageReserved(page); +} + +static void kvm_set_page_dirty(struct page *page) +{ + if (kvm_is_ad_tracked_page(page)) + SetPageDirty(page); +} + +static void kvm_set_page_accessed(struct page *page) +{ + if (kvm_is_ad_tracked_page(page)) + mark_page_accessed(page); +} + +void kvm_release_page_clean(struct page *page) +{ + if (!page) + return; + + kvm_set_page_accessed(page); + put_page(page); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_release_page_clean); + +void kvm_release_page_dirty(struct page *page) +{ + if (!page) + return; + + kvm_set_page_dirty(page); + kvm_release_page_clean(page); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_release_page_dirty); + +static kvm_pfn_t kvm_resolve_pfn(struct kvm_follow_pfn *kfp, struct page *page, + struct follow_pfnmap_args *map, bool writable) +{ + kvm_pfn_t pfn; + + WARN_ON_ONCE(!!page == !!map); + + if (kfp->map_writable) + *kfp->map_writable = writable; + + if (map) + pfn = map->pfn; + else + pfn = page_to_pfn(page); + + *kfp->refcounted_page = page; + + return pfn; +} + +/* + * The fast path to get the writable pfn which will be stored in @pfn, + * true indicates success, otherwise false is returned. + */ +static bool hva_to_pfn_fast(struct kvm_follow_pfn *kfp, kvm_pfn_t *pfn) +{ + struct page *page; + bool r; + + /* + * Try the fast-only path when the caller wants to pin/get the page for + * writing. If the caller only wants to read the page, KVM must go + * down the full, slow path in order to avoid racing an operation that + * breaks Copy-on-Write (CoW), e.g. so that KVM doesn't end up pointing + * at the old, read-only page while mm/ points at a new, writable page. + */ + if (!((kfp->flags & FOLL_WRITE) || kfp->map_writable)) + return false; + + if (kfp->pin) + r = pin_user_pages_fast(kfp->hva, 1, FOLL_WRITE, &page) == 1; + else + r = get_user_page_fast_only(kfp->hva, FOLL_WRITE, &page); + + if (r) { + *pfn = kvm_resolve_pfn(kfp, page, NULL, true); + return true; + } + + return false; +} + +/* + * The slow path to get the pfn of the specified host virtual address, + * 1 indicates success, -errno is returned if error is detected. + */ +static int hva_to_pfn_slow(struct kvm_follow_pfn *kfp, kvm_pfn_t *pfn) +{ + /* + * When a VCPU accesses a page that is not mapped into the secondary + * MMU, we lookup the page using GUP to map it, so the guest VCPU can + * make progress. We always want to honor NUMA hinting faults in that + * case, because GUP usage corresponds to memory accesses from the VCPU. + * Otherwise, we'd not trigger NUMA hinting faults once a page is + * mapped into the secondary MMU and gets accessed by a VCPU. + * + * Note that get_user_page_fast_only() and FOLL_WRITE for now + * implicitly honor NUMA hinting faults and don't need this flag. + */ + unsigned int flags = FOLL_HWPOISON | FOLL_HONOR_NUMA_FAULT | kfp->flags; + struct page *page, *wpage; + int npages; + + if (kfp->pin) + npages = pin_user_pages_unlocked(kfp->hva, 1, &page, flags); + else + npages = get_user_pages_unlocked(kfp->hva, 1, &page, flags); + if (npages != 1) + return npages; + + /* + * Pinning is mutually exclusive with opportunistically mapping a read + * fault as writable, as KVM should never pin pages when mapping memory + * into the guest (pinning is only for direct accesses from KVM). + */ + if (WARN_ON_ONCE(kfp->map_writable && kfp->pin)) + goto out; + + /* map read fault as writable if possible */ + if (!(flags & FOLL_WRITE) && kfp->map_writable && + get_user_page_fast_only(kfp->hva, FOLL_WRITE, &wpage)) { + put_page(page); + page = wpage; + flags |= FOLL_WRITE; + } + +out: + *pfn = kvm_resolve_pfn(kfp, page, NULL, flags & FOLL_WRITE); + return npages; +} + +static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault) +{ + if (unlikely(!(vma->vm_flags & VM_READ))) + return false; + + if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE)))) + return false; + + return true; +} + +static int hva_to_pfn_remapped(struct vm_area_struct *vma, + struct kvm_follow_pfn *kfp, kvm_pfn_t *p_pfn) +{ + struct follow_pfnmap_args args = { .vma = vma, .address = kfp->hva }; + bool write_fault = kfp->flags & FOLL_WRITE; + int r; + + /* + * Remapped memory cannot be pinned in any meaningful sense. Bail if + * the caller wants to pin the page, i.e. access the page outside of + * MMU notifier protection, and unsafe umappings are disallowed. + */ + if (kfp->pin && !allow_unsafe_mappings) + return -EINVAL; + + r = follow_pfnmap_start(&args); + if (r) { + /* + * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does + * not call the fault handler, so do it here. + */ + bool unlocked = false; + r = fixup_user_fault(current->mm, kfp->hva, + (write_fault ? FAULT_FLAG_WRITE : 0), + &unlocked); + if (unlocked) + return -EAGAIN; + if (r) + return r; + + r = follow_pfnmap_start(&args); + if (r) + return r; + } + + if (write_fault && !args.writable) { + *p_pfn = KVM_PFN_ERR_RO_FAULT; + goto out; + } + + *p_pfn = kvm_resolve_pfn(kfp, NULL, &args, args.writable); +out: + follow_pfnmap_end(&args); + return r; +} + +kvm_pfn_t hva_to_pfn(struct kvm_follow_pfn *kfp) +{ + struct vm_area_struct *vma; + kvm_pfn_t pfn; + int npages, r; + + might_sleep(); + + if (WARN_ON_ONCE(!kfp->refcounted_page)) + return KVM_PFN_ERR_FAULT; + + if (hva_to_pfn_fast(kfp, &pfn)) + return pfn; + + npages = hva_to_pfn_slow(kfp, &pfn); + if (npages == 1) + return pfn; + if (npages == -EINTR || npages == -EAGAIN) + return KVM_PFN_ERR_SIGPENDING; + if (npages == -EHWPOISON) + return KVM_PFN_ERR_HWPOISON; + + mmap_read_lock(current->mm); +retry: + vma = vma_lookup(current->mm, kfp->hva); + + if (vma == NULL) + pfn = KVM_PFN_ERR_FAULT; + else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) { + r = hva_to_pfn_remapped(vma, kfp, &pfn); + if (r == -EAGAIN) + goto retry; + if (r < 0) + pfn = KVM_PFN_ERR_FAULT; + } else { + if ((kfp->flags & FOLL_NOWAIT) && + vma_is_valid(vma, kfp->flags & FOLL_WRITE)) + pfn = KVM_PFN_ERR_NEEDS_IO; + else + pfn = KVM_PFN_ERR_FAULT; + } + mmap_read_unlock(current->mm); + return pfn; +} + +static kvm_pfn_t kvm_follow_pfn(struct kvm_follow_pfn *kfp) +{ + kfp->hva = __gfn_to_hva_many(kfp->slot, kfp->gfn, NULL, + kfp->flags & FOLL_WRITE); + + if (kfp->hva == KVM_HVA_ERR_RO_BAD) + return KVM_PFN_ERR_RO_FAULT; + + if (kvm_is_error_hva(kfp->hva)) + return KVM_PFN_NOSLOT; + + if (memslot_is_readonly(kfp->slot) && kfp->map_writable) { + *kfp->map_writable = false; + kfp->map_writable = NULL; + } + + return hva_to_pfn(kfp); +} + +kvm_pfn_t __kvm_faultin_pfn(const struct kvm_memory_slot *slot, gfn_t gfn, + unsigned int foll, bool *writable, + struct page **refcounted_page) +{ + struct kvm_follow_pfn kfp = { + .slot = slot, + .gfn = gfn, + .flags = foll, + .map_writable = writable, + .refcounted_page = refcounted_page, + }; + + if (WARN_ON_ONCE(!writable || !refcounted_page)) + return KVM_PFN_ERR_FAULT; + + *writable = false; + *refcounted_page = NULL; + + return kvm_follow_pfn(&kfp); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_faultin_pfn); + +int kvm_prefetch_pages(struct kvm_memory_slot *slot, gfn_t gfn, + struct page **pages, int nr_pages) +{ + unsigned long addr; + gfn_t entry = 0; + + addr = gfn_to_hva_many(slot, gfn, &entry); + if (kvm_is_error_hva(addr)) + return -1; + + if (entry < nr_pages) + return 0; + + return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_prefetch_pages); + +/* + * Don't use this API unless you are absolutely, positively certain that KVM + * needs to get a struct page, e.g. to pin the page for firmware DMA. + * + * FIXME: Users of this API likely need to FOLL_PIN the page, not just elevate + * its refcount. + */ +struct page *__gfn_to_page(struct kvm *kvm, gfn_t gfn, bool write) +{ + struct page *refcounted_page = NULL; + struct kvm_follow_pfn kfp = { + .slot = gfn_to_memslot(kvm, gfn), + .gfn = gfn, + .flags = write ? FOLL_WRITE : 0, + .refcounted_page = &refcounted_page, + }; + + (void)kvm_follow_pfn(&kfp); + return refcounted_page; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(__gfn_to_page); + +int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map, + bool writable) +{ + struct kvm_follow_pfn kfp = { + .slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn), + .gfn = gfn, + .flags = writable ? FOLL_WRITE : 0, + .refcounted_page = &map->pinned_page, + .pin = true, + }; + + map->pinned_page = NULL; + map->page = NULL; + map->hva = NULL; + map->gfn = gfn; + map->writable = writable; + + map->pfn = kvm_follow_pfn(&kfp); + if (is_error_noslot_pfn(map->pfn)) + return -EINVAL; + + if (pfn_valid(map->pfn)) { + map->page = pfn_to_page(map->pfn); + map->hva = kmap(map->page); +#ifdef CONFIG_HAS_IOMEM + } else { + map->hva = memremap(pfn_to_hpa(map->pfn), PAGE_SIZE, MEMREMAP_WB); +#endif + } + + return map->hva ? 0 : -EFAULT; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_vcpu_map); + +void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map) +{ + if (!map->hva) + return; + + if (map->page) + kunmap(map->page); +#ifdef CONFIG_HAS_IOMEM + else + memunmap(map->hva); +#endif + + if (map->writable) + kvm_vcpu_mark_page_dirty(vcpu, map->gfn); + + if (map->pinned_page) { + if (map->writable) + kvm_set_page_dirty(map->pinned_page); + kvm_set_page_accessed(map->pinned_page); + unpin_user_page(map->pinned_page); + } + + map->hva = NULL; + map->page = NULL; + map->pinned_page = NULL; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_unmap); + +static int next_segment(unsigned long len, int offset) +{ + if (len > PAGE_SIZE - offset) + return PAGE_SIZE - offset; + else + return len; +} + +/* Copy @len bytes from guest memory at '(@gfn * PAGE_SIZE) + @offset' to @data */ +static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn, + void *data, int offset, int len) +{ + int r; + unsigned long addr; + + if (WARN_ON_ONCE(offset + len > PAGE_SIZE)) + return -EFAULT; + + addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); + if (kvm_is_error_hva(addr)) + return -EFAULT; + r = __copy_from_user(data, (void __user *)addr + offset, len); + if (r) + return -EFAULT; + return 0; +} + +int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, + int len) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return __kvm_read_guest_page(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_guest_page); + +int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, + int offset, int len) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return __kvm_read_guest_page(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest_page); + +int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_read_guest_page(kvm, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_guest); + +int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest); + +static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn, + void *data, int offset, unsigned long len) +{ + int r; + unsigned long addr; + + if (WARN_ON_ONCE(offset + len > PAGE_SIZE)) + return -EFAULT; + + addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); + if (kvm_is_error_hva(addr)) + return -EFAULT; + pagefault_disable(); + r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len); + pagefault_enable(); + if (r) + return -EFAULT; + return 0; +} + +int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa, + void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + int offset = offset_in_page(gpa); + + return __kvm_read_guest_atomic(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest_atomic); + +/* Copy @len bytes from @data into guest memory at '(@gfn * PAGE_SIZE) + @offset' */ +static int __kvm_write_guest_page(struct kvm *kvm, + struct kvm_memory_slot *memslot, gfn_t gfn, + const void *data, int offset, int len) +{ + int r; + unsigned long addr; + + if (WARN_ON_ONCE(offset + len > PAGE_SIZE)) + return -EFAULT; + + addr = gfn_to_hva_memslot(memslot, gfn); + if (kvm_is_error_hva(addr)) + return -EFAULT; + r = __copy_to_user((void __user *)addr + offset, data, len); + if (r) + return -EFAULT; + mark_page_dirty_in_slot(kvm, memslot, gfn); + return 0; +} + +int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, + const void *data, int offset, int len) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return __kvm_write_guest_page(kvm, slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_write_guest_page); + +int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, + const void *data, int offset, int len) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return __kvm_write_guest_page(vcpu->kvm, slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_write_guest_page); + +int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, + unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_write_guest_page(kvm, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_write_guest); + +int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data, + unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_write_guest); + +static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots, + struct gfn_to_hva_cache *ghc, + gpa_t gpa, unsigned long len) +{ + int offset = offset_in_page(gpa); + gfn_t start_gfn = gpa >> PAGE_SHIFT; + gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT; + gfn_t nr_pages_needed = end_gfn - start_gfn + 1; + gfn_t nr_pages_avail; + + /* Update ghc->generation before performing any error checks. */ + ghc->generation = slots->generation; + + if (start_gfn > end_gfn) { + ghc->hva = KVM_HVA_ERR_BAD; + return -EINVAL; + } + + /* + * If the requested region crosses two memslots, we still + * verify that the entire region is valid here. + */ + for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) { + ghc->memslot = __gfn_to_memslot(slots, start_gfn); + ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn, + &nr_pages_avail); + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + } + + /* Use the slow path for cross page reads and writes. */ + if (nr_pages_needed == 1) + ghc->hva += offset; + else + ghc->memslot = NULL; + + ghc->gpa = gpa; + ghc->len = len; + return 0; +} + +int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + gpa_t gpa, unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gfn_to_hva_cache_init); + +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned int offset, + unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + int r; + gpa_t gpa = ghc->gpa + offset; + + if (WARN_ON_ONCE(len + offset > ghc->len)) + return -EINVAL; + + if (slots->generation != ghc->generation) { + if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) + return -EFAULT; + } + + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + + if (unlikely(!ghc->memslot)) + return kvm_write_guest(kvm, gpa, data, len); + + r = __copy_to_user((void __user *)ghc->hva + offset, data, len); + if (r) + return -EFAULT; + mark_page_dirty_in_slot(kvm, ghc->memslot, gpa >> PAGE_SHIFT); + + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_write_guest_offset_cached); + +int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_write_guest_cached); + +int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned int offset, + unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + int r; + gpa_t gpa = ghc->gpa + offset; + + if (WARN_ON_ONCE(len + offset > ghc->len)) + return -EINVAL; + + if (slots->generation != ghc->generation) { + if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) + return -EFAULT; + } + + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + + if (unlikely(!ghc->memslot)) + return kvm_read_guest(kvm, gpa, data, len); + + r = __copy_from_user(data, (void __user *)ghc->hva + offset, len); + if (r) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_guest_offset_cached); + +int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_read_guest_offset_cached(kvm, ghc, data, 0, len); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_guest_cached); + +int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len) +{ + const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0))); + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_clear_guest); + +void mark_page_dirty_in_slot(struct kvm *kvm, + const struct kvm_memory_slot *memslot, + gfn_t gfn) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + +#ifdef CONFIG_HAVE_KVM_DIRTY_RING + if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm)) + return; + + WARN_ON_ONCE(!vcpu && refcount_read(&kvm->users_count) && + !kvm_arch_allow_write_without_running_vcpu(kvm)); +#endif + + if (memslot && kvm_slot_dirty_track_enabled(memslot)) { + unsigned long rel_gfn = gfn - memslot->base_gfn; + u32 slot = (memslot->as_id << 16) | memslot->id; + + if (kvm->dirty_ring_size && vcpu) + kvm_dirty_ring_push(vcpu, slot, rel_gfn); + else if (memslot->dirty_bitmap) + set_bit_le(rel_gfn, memslot->dirty_bitmap); + } +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(mark_page_dirty_in_slot); + +void mark_page_dirty(struct kvm *kvm, gfn_t gfn) +{ + struct kvm_memory_slot *memslot; + + memslot = gfn_to_memslot(kvm, gfn); + mark_page_dirty_in_slot(kvm, memslot, gfn); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(mark_page_dirty); + +void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memory_slot *memslot; + + memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + mark_page_dirty_in_slot(vcpu->kvm, memslot, gfn); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_mark_page_dirty); + +void kvm_sigset_activate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + /* + * This does a lockless modification of ->real_blocked, which is fine + * because, only current can change ->real_blocked and all readers of + * ->real_blocked don't care as long ->real_blocked is always a subset + * of ->blocked. + */ + sigprocmask(SIG_SETMASK, &vcpu->sigset, ¤t->real_blocked); +} + +void kvm_sigset_deactivate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + sigprocmask(SIG_SETMASK, ¤t->real_blocked, NULL); + sigemptyset(¤t->real_blocked); +} + +static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + unsigned int old, val, grow, grow_start; + + old = val = vcpu->halt_poll_ns; + grow_start = READ_ONCE(halt_poll_ns_grow_start); + grow = READ_ONCE(halt_poll_ns_grow); + if (!grow) + goto out; + + val *= grow; + if (val < grow_start) + val = grow_start; + + vcpu->halt_poll_ns = val; +out: + trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old); +} + +static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + unsigned int old, val, shrink, grow_start; + + old = val = vcpu->halt_poll_ns; + shrink = READ_ONCE(halt_poll_ns_shrink); + grow_start = READ_ONCE(halt_poll_ns_grow_start); + if (shrink == 0) + val = 0; + else + val /= shrink; + + if (val < grow_start) + val = 0; + + vcpu->halt_poll_ns = val; + trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old); +} + +static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) +{ + int ret = -EINTR; + int idx = srcu_read_lock(&vcpu->kvm->srcu); + + if (kvm_arch_vcpu_runnable(vcpu)) + goto out; + if (kvm_cpu_has_pending_timer(vcpu)) + goto out; + if (signal_pending(current)) + goto out; + if (kvm_check_request(KVM_REQ_UNBLOCK, vcpu)) + goto out; + + ret = 0; +out: + srcu_read_unlock(&vcpu->kvm->srcu, idx); + return ret; +} + +/* + * Block the vCPU until the vCPU is runnable, an event arrives, or a signal is + * pending. This is mostly used when halting a vCPU, but may also be used + * directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI. + */ +bool kvm_vcpu_block(struct kvm_vcpu *vcpu) +{ + struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); + bool waited = false; + + vcpu->stat.generic.blocking = 1; + + preempt_disable(); + kvm_arch_vcpu_blocking(vcpu); + prepare_to_rcuwait(wait); + preempt_enable(); + + for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + + if (kvm_vcpu_check_block(vcpu) < 0) + break; + + waited = true; + schedule(); + } + + preempt_disable(); + finish_rcuwait(wait); + kvm_arch_vcpu_unblocking(vcpu); + preempt_enable(); + + vcpu->stat.generic.blocking = 0; + + return waited; +} + +static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, + ktime_t end, bool success) +{ + struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic; + u64 poll_ns = ktime_to_ns(ktime_sub(end, start)); + + ++vcpu->stat.generic.halt_attempted_poll; + + if (success) { + ++vcpu->stat.generic.halt_successful_poll; + + if (!vcpu_valid_wakeup(vcpu)) + ++vcpu->stat.generic.halt_poll_invalid; + + stats->halt_poll_success_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns); + } else { + stats->halt_poll_fail_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns); + } +} + +static unsigned int kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + + if (kvm->override_halt_poll_ns) { + /* + * Ensure kvm->max_halt_poll_ns is not read before + * kvm->override_halt_poll_ns. + * + * Pairs with the smp_wmb() when enabling KVM_CAP_HALT_POLL. + */ + smp_rmb(); + return READ_ONCE(kvm->max_halt_poll_ns); + } + + return READ_ONCE(halt_poll_ns); +} + +/* + * Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc... If halt + * polling is enabled, busy wait for a short time before blocking to avoid the + * expensive block+unblock sequence if a wake event arrives soon after the vCPU + * is halted. + */ +void kvm_vcpu_halt(struct kvm_vcpu *vcpu) +{ + unsigned int max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu); + bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); + ktime_t start, cur, poll_end; + bool waited = false; + bool do_halt_poll; + u64 halt_ns; + + if (vcpu->halt_poll_ns > max_halt_poll_ns) + vcpu->halt_poll_ns = max_halt_poll_ns; + + do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns; + + start = cur = poll_end = ktime_get(); + if (do_halt_poll) { + ktime_t stop = ktime_add_ns(start, vcpu->halt_poll_ns); + + do { + if (kvm_vcpu_check_block(vcpu) < 0) + goto out; + cpu_relax(); + poll_end = cur = ktime_get(); + } while (kvm_vcpu_can_poll(cur, stop)); + } + + waited = kvm_vcpu_block(vcpu); + + cur = ktime_get(); + if (waited) { + vcpu->stat.generic.halt_wait_ns += + ktime_to_ns(cur) - ktime_to_ns(poll_end); + KVM_STATS_LOG_HIST_UPDATE(vcpu->stat.generic.halt_wait_hist, + ktime_to_ns(cur) - ktime_to_ns(poll_end)); + } +out: + /* The total time the vCPU was "halted", including polling time. */ + halt_ns = ktime_to_ns(cur) - ktime_to_ns(start); + + /* + * Note, halt-polling is considered successful so long as the vCPU was + * never actually scheduled out, i.e. even if the wake event arrived + * after of the halt-polling loop itself, but before the full wait. + */ + if (do_halt_poll) + update_halt_poll_stats(vcpu, start, poll_end, !waited); + + if (halt_poll_allowed) { + /* Recompute the max halt poll time in case it changed. */ + max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu); + + if (!vcpu_valid_wakeup(vcpu)) { + shrink_halt_poll_ns(vcpu); + } else if (max_halt_poll_ns) { + if (halt_ns <= vcpu->halt_poll_ns) + ; + /* we had a long block, shrink polling */ + else if (vcpu->halt_poll_ns && + halt_ns > max_halt_poll_ns) + shrink_halt_poll_ns(vcpu); + /* we had a short halt and our poll time is too small */ + else if (vcpu->halt_poll_ns < max_halt_poll_ns && + halt_ns < max_halt_poll_ns) + grow_halt_poll_ns(vcpu); + } else { + vcpu->halt_poll_ns = 0; + } + } + + trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu)); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_halt); + +bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu) +{ + if (__kvm_vcpu_wake_up(vcpu)) { + WRITE_ONCE(vcpu->ready, true); + ++vcpu->stat.generic.halt_wakeup; + return true; + } + + return false; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_wake_up); + +#ifndef CONFIG_S390 +/* + * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode. + */ +void __kvm_vcpu_kick(struct kvm_vcpu *vcpu, bool wait) +{ + int me, cpu; + + if (kvm_vcpu_wake_up(vcpu)) + return; + + me = get_cpu(); + /* + * The only state change done outside the vcpu mutex is IN_GUEST_MODE + * to EXITING_GUEST_MODE. Therefore the moderately expensive "should + * kick" check does not need atomic operations if kvm_vcpu_kick is used + * within the vCPU thread itself. + */ + if (vcpu == __this_cpu_read(kvm_running_vcpu)) { + if (vcpu->mode == IN_GUEST_MODE) + WRITE_ONCE(vcpu->mode, EXITING_GUEST_MODE); + goto out; + } + + /* + * Note, the vCPU could get migrated to a different pCPU at any point + * after kvm_arch_vcpu_should_kick(), which could result in sending an + * IPI to the previous pCPU. But, that's ok because the purpose of the + * IPI is to force the vCPU to leave IN_GUEST_MODE, and migrating the + * vCPU also requires it to leave IN_GUEST_MODE. + */ + if (kvm_arch_vcpu_should_kick(vcpu)) { + cpu = READ_ONCE(vcpu->cpu); + if (cpu != me && (unsigned int)cpu < nr_cpu_ids && cpu_online(cpu)) { + /* + * Use a reschedule IPI to kick the vCPU if the caller + * doesn't need to wait for a response, as KVM allows + * kicking vCPUs while IRQs are disabled, but using the + * SMP function call framework with IRQs disabled can + * deadlock due to taking cross-CPU locks. + */ + if (wait) + smp_call_function_single(cpu, ack_kick, NULL, wait); + else + smp_send_reschedule(cpu); + } + } +out: + put_cpu(); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_vcpu_kick); +#endif /* !CONFIG_S390 */ + +int kvm_vcpu_yield_to(struct kvm_vcpu *target) +{ + struct task_struct *task = NULL; + int ret; + + if (!read_trylock(&target->pid_lock)) + return 0; + + if (target->pid) + task = get_pid_task(target->pid, PIDTYPE_PID); + + read_unlock(&target->pid_lock); + + if (!task) + return 0; + ret = yield_to(task, 1); + put_task_struct(task); + + return ret; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_yield_to); + +/* + * Helper that checks whether a VCPU is eligible for directed yield. + * Most eligible candidate to yield is decided by following heuristics: + * + * (a) VCPU which has not done pl-exit or cpu relax intercepted recently + * (preempted lock holder), indicated by @in_spin_loop. + * Set at the beginning and cleared at the end of interception/PLE handler. + * + * (b) VCPU which has done pl-exit/ cpu relax intercepted but did not get + * chance last time (mostly it has become eligible now since we have probably + * yielded to lockholder in last iteration. This is done by toggling + * @dy_eligible each time a VCPU checked for eligibility.) + * + * Yielding to a recently pl-exited/cpu relax intercepted VCPU before yielding + * to preempted lock-holder could result in wrong VCPU selection and CPU + * burning. Giving priority for a potential lock-holder increases lock + * progress. + * + * Since algorithm is based on heuristics, accessing another VCPU data without + * locking does not harm. It may result in trying to yield to same VCPU, fail + * and continue with next VCPU and so on. + */ +static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT + bool eligible; + + eligible = !vcpu->spin_loop.in_spin_loop || + vcpu->spin_loop.dy_eligible; + + if (vcpu->spin_loop.in_spin_loop) + kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible); + + return eligible; +#else + return true; +#endif +} + +/* + * Unlike kvm_arch_vcpu_runnable, this function is called outside + * a vcpu_load/vcpu_put pair. However, for most architectures + * kvm_arch_vcpu_runnable does not require vcpu_load. + */ +bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu) +{ + return kvm_arch_vcpu_runnable(vcpu); +} + +static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu) +{ + if (kvm_arch_dy_runnable(vcpu)) + return true; + +#ifdef CONFIG_KVM_ASYNC_PF + if (!list_empty_careful(&vcpu->async_pf.done)) + return true; +#endif + + return false; +} + +/* + * By default, simply query the target vCPU's current mode when checking if a + * vCPU was preempted in kernel mode. All architectures except x86 (or more + * specifical, except VMX) allow querying whether or not a vCPU is in kernel + * mode even if the vCPU is NOT loaded, i.e. using kvm_arch_vcpu_in_kernel() + * directly for cross-vCPU checks is functionally correct and accurate. + */ +bool __weak kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu) +{ + return kvm_arch_vcpu_in_kernel(vcpu); +} + +bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu) +{ + return false; +} + +void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) +{ + int nr_vcpus, start, i, idx, yielded; + struct kvm *kvm = me->kvm; + struct kvm_vcpu *vcpu; + int try = 3; + + nr_vcpus = atomic_read(&kvm->online_vcpus); + if (nr_vcpus < 2) + return; + + /* Pairs with the smp_wmb() in kvm_vm_ioctl_create_vcpu(). */ + smp_rmb(); + + kvm_vcpu_set_in_spin_loop(me, true); + + /* + * The current vCPU ("me") is spinning in kernel mode, i.e. is likely + * waiting for a resource to become available. Attempt to yield to a + * vCPU that is runnable, but not currently running, e.g. because the + * vCPU was preempted by a higher priority task. With luck, the vCPU + * that was preempted is holding a lock or some other resource that the + * current vCPU is waiting to acquire, and yielding to the other vCPU + * will allow it to make forward progress and release the lock (or kick + * the spinning vCPU, etc). + * + * Since KVM has no insight into what exactly the guest is doing, + * approximate a round-robin selection by iterating over all vCPUs, + * starting at the last boosted vCPU. I.e. if N=kvm->last_boosted_vcpu, + * iterate over vCPU[N+1]..vCPU[N-1], wrapping as needed. + * + * Note, this is inherently racy, e.g. if multiple vCPUs are spinning, + * they may all try to yield to the same vCPU(s). But as above, this + * is all best effort due to KVM's lack of visibility into the guest. + */ + start = READ_ONCE(kvm->last_boosted_vcpu) + 1; + for (i = 0; i < nr_vcpus; i++) { + idx = (start + i) % nr_vcpus; + if (idx == me->vcpu_idx) + continue; + + vcpu = xa_load(&kvm->vcpu_array, idx); + if (!READ_ONCE(vcpu->ready)) + continue; + if (kvm_vcpu_is_blocking(vcpu) && !vcpu_dy_runnable(vcpu)) + continue; + + /* + * Treat the target vCPU as being in-kernel if it has a pending + * interrupt, as the vCPU trying to yield may be spinning + * waiting on IPI delivery, i.e. the target vCPU is in-kernel + * for the purposes of directed yield. + */ + if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode && + !kvm_arch_dy_has_pending_interrupt(vcpu) && + !kvm_arch_vcpu_preempted_in_kernel(vcpu)) + continue; + + if (!kvm_vcpu_eligible_for_directed_yield(vcpu)) + continue; + + yielded = kvm_vcpu_yield_to(vcpu); + if (yielded > 0) { + WRITE_ONCE(kvm->last_boosted_vcpu, idx); + break; + } else if (yielded < 0 && !--try) { + break; + } + } + kvm_vcpu_set_in_spin_loop(me, false); + + /* Ensure vcpu is not eligible during next spinloop */ + kvm_vcpu_set_dy_eligible(me, false); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_on_spin); + +static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff) +{ +#ifdef CONFIG_HAVE_KVM_DIRTY_RING + return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) && + (pgoff < KVM_DIRTY_LOG_PAGE_OFFSET + + kvm->dirty_ring_size / PAGE_SIZE); +#else + return false; +#endif +} + +static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf) +{ + struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data; + struct page *page; + + if (vmf->pgoff == 0) + page = virt_to_page(vcpu->run); +#ifdef CONFIG_X86 + else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET) + page = virt_to_page(vcpu->arch.pio_data); +#endif +#ifdef CONFIG_KVM_MMIO + else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET) + page = virt_to_page(vcpu->kvm->coalesced_mmio_ring); +#endif + else if (kvm_page_in_dirty_ring(vcpu->kvm, vmf->pgoff)) + page = kvm_dirty_ring_get_page( + &vcpu->dirty_ring, + vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET); + else + return kvm_arch_vcpu_fault(vcpu, vmf); + get_page(page); + vmf->page = page; + return 0; +} + +static const struct vm_operations_struct kvm_vcpu_vm_ops = { + .fault = kvm_vcpu_fault, +}; + +static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct kvm_vcpu *vcpu = file->private_data; + unsigned long pages = vma_pages(vma); + + if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) || + kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) && + ((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED))) + return -EINVAL; + + vma->vm_ops = &kvm_vcpu_vm_ops; + return 0; +} + +static int kvm_vcpu_release(struct inode *inode, struct file *filp) +{ + struct kvm_vcpu *vcpu = filp->private_data; + + kvm_put_kvm(vcpu->kvm); + return 0; +} + +static struct file_operations kvm_vcpu_fops = { + .release = kvm_vcpu_release, + .unlocked_ioctl = kvm_vcpu_ioctl, + .mmap = kvm_vcpu_mmap, + .llseek = noop_llseek, + KVM_COMPAT(kvm_vcpu_compat_ioctl), +}; + +/* + * Allocates an inode for the vcpu. + */ +static int create_vcpu_fd(struct kvm_vcpu *vcpu) +{ + char name[8 + 1 + ITOA_MAX_LEN + 1]; + + snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id); + return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC); +} + +#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS +static int vcpu_get_pid(void *data, u64 *val) +{ + struct kvm_vcpu *vcpu = data; + + read_lock(&vcpu->pid_lock); + *val = pid_nr(vcpu->pid); + read_unlock(&vcpu->pid_lock); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n"); + +static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) +{ + struct dentry *debugfs_dentry; + char dir_name[ITOA_MAX_LEN * 2]; + + if (!debugfs_initialized()) + return; + + snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id); + debugfs_dentry = debugfs_create_dir(dir_name, + vcpu->kvm->debugfs_dentry); + debugfs_create_file("pid", 0444, debugfs_dentry, vcpu, + &vcpu_get_pid_fops); + + kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry); +} +#endif + +/* + * Creates some virtual cpus. Good luck creating more than one. + */ +static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id) +{ + int r; + struct kvm_vcpu *vcpu; + struct page *page; + + /* + * KVM tracks vCPU IDs as 'int', be kind to userspace and reject + * too-large values instead of silently truncating. + * + * Ensure KVM_MAX_VCPU_IDS isn't pushed above INT_MAX without first + * changing the storage type (at the very least, IDs should be tracked + * as unsigned ints). + */ + BUILD_BUG_ON(KVM_MAX_VCPU_IDS > INT_MAX); + if (id >= KVM_MAX_VCPU_IDS) + return -EINVAL; + + mutex_lock(&kvm->lock); + if (kvm->created_vcpus >= kvm->max_vcpus) { + mutex_unlock(&kvm->lock); + return -EINVAL; + } + + r = kvm_arch_vcpu_precreate(kvm, id); + if (r) { + mutex_unlock(&kvm->lock); + return r; + } + + kvm->created_vcpus++; + mutex_unlock(&kvm->lock); + + vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT); + if (!vcpu) { + r = -ENOMEM; + goto vcpu_decrement; + } + + BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE); + page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + if (!page) { + r = -ENOMEM; + goto vcpu_free; + } + vcpu->run = page_address(page); + + kvm_vcpu_init(vcpu, kvm, id); + + r = kvm_arch_vcpu_create(vcpu); + if (r) + goto vcpu_free_run_page; + + if (kvm->dirty_ring_size) { + r = kvm_dirty_ring_alloc(kvm, &vcpu->dirty_ring, + id, kvm->dirty_ring_size); + if (r) + goto arch_vcpu_destroy; + } + + mutex_lock(&kvm->lock); + + if (kvm_get_vcpu_by_id(kvm, id)) { + r = -EEXIST; + goto unlock_vcpu_destroy; + } + + vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus); + r = xa_insert(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, GFP_KERNEL_ACCOUNT); + WARN_ON_ONCE(r == -EBUSY); + if (r) + goto unlock_vcpu_destroy; + + /* + * Now it's all set up, let userspace reach it. Grab the vCPU's mutex + * so that userspace can't invoke vCPU ioctl()s until the vCPU is fully + * visible (per online_vcpus), e.g. so that KVM doesn't get tricked + * into a NULL-pointer dereference because KVM thinks the _current_ + * vCPU doesn't exist. As a bonus, taking vcpu->mutex ensures lockdep + * knows it's taken *inside* kvm->lock. + */ + mutex_lock(&vcpu->mutex); + kvm_get_kvm(kvm); + r = create_vcpu_fd(vcpu); + if (r < 0) + goto kvm_put_xa_erase; + + /* + * Pairs with smp_rmb() in kvm_get_vcpu. Store the vcpu + * pointer before kvm->online_vcpu's incremented value. + */ + smp_wmb(); + atomic_inc(&kvm->online_vcpus); + mutex_unlock(&vcpu->mutex); + + mutex_unlock(&kvm->lock); + kvm_arch_vcpu_postcreate(vcpu); + kvm_create_vcpu_debugfs(vcpu); + return r; + +kvm_put_xa_erase: + mutex_unlock(&vcpu->mutex); + kvm_put_kvm_no_destroy(kvm); + xa_erase(&kvm->vcpu_array, vcpu->vcpu_idx); +unlock_vcpu_destroy: + mutex_unlock(&kvm->lock); + kvm_dirty_ring_free(&vcpu->dirty_ring); +arch_vcpu_destroy: + kvm_arch_vcpu_destroy(vcpu); +vcpu_free_run_page: + free_page((unsigned long)vcpu->run); +vcpu_free: + kmem_cache_free(kvm_vcpu_cache, vcpu); +vcpu_decrement: + mutex_lock(&kvm->lock); + kvm->created_vcpus--; + mutex_unlock(&kvm->lock); + return r; +} + +static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset) +{ + if (sigset) { + sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP)); + vcpu->sigset_active = 1; + vcpu->sigset = *sigset; + } else + vcpu->sigset_active = 0; + return 0; +} + +static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm_vcpu *vcpu = file->private_data; + + return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header, + &kvm_vcpu_stats_desc[0], &vcpu->stat, + sizeof(vcpu->stat), user_buffer, size, offset); +} + +static int kvm_vcpu_stats_release(struct inode *inode, struct file *file) +{ + struct kvm_vcpu *vcpu = file->private_data; + + kvm_put_kvm(vcpu->kvm); + return 0; +} + +static const struct file_operations kvm_vcpu_stats_fops = { + .owner = THIS_MODULE, + .read = kvm_vcpu_stats_read, + .release = kvm_vcpu_stats_release, + .llseek = noop_llseek, +}; + +static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu) +{ + int fd; + struct file *file; + char name[15 + ITOA_MAX_LEN + 1]; + + snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id); + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile_fmode(name, &kvm_vcpu_stats_fops, vcpu, + O_RDONLY, FMODE_PREAD); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + + kvm_get_kvm(vcpu->kvm); + fd_install(fd, file); + + return fd; +} + +#ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY +static int kvm_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu, + struct kvm_pre_fault_memory *range) +{ + int idx; + long r; + u64 full_size; + + if (range->flags) + return -EINVAL; + + if (!PAGE_ALIGNED(range->gpa) || + !PAGE_ALIGNED(range->size) || + range->gpa + range->size <= range->gpa) + return -EINVAL; + + vcpu_load(vcpu); + idx = srcu_read_lock(&vcpu->kvm->srcu); + + full_size = range->size; + do { + if (signal_pending(current)) { + r = -EINTR; + break; + } + + r = kvm_arch_vcpu_pre_fault_memory(vcpu, range); + if (WARN_ON_ONCE(r == 0 || r == -EIO)) + break; + + if (r < 0) + break; + + range->size -= r; + range->gpa += r; + cond_resched(); + } while (range->size); + + srcu_read_unlock(&vcpu->kvm->srcu, idx); + vcpu_put(vcpu); + + /* Return success if at least one page was mapped successfully. */ + return full_size == range->size ? r : 0; +} +#endif + +static int kvm_wait_for_vcpu_online(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + + /* + * In practice, this happy path will always be taken, as a well-behaved + * VMM will never invoke a vCPU ioctl() before KVM_CREATE_VCPU returns. + */ + if (likely(vcpu->vcpu_idx < atomic_read(&kvm->online_vcpus))) + return 0; + + /* + * Acquire and release the vCPU's mutex to wait for vCPU creation to + * complete (kvm_vm_ioctl_create_vcpu() holds the mutex until the vCPU + * is fully online). + */ + if (mutex_lock_killable(&vcpu->mutex)) + return -EINTR; + + mutex_unlock(&vcpu->mutex); + + if (WARN_ON_ONCE(!kvm_get_vcpu(kvm, vcpu->vcpu_idx))) + return -EIO; + + return 0; +} + +static long kvm_vcpu_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm_vcpu *vcpu = filp->private_data; + void __user *argp = (void __user *)arg; + int r; + struct kvm_fpu *fpu = NULL; + struct kvm_sregs *kvm_sregs = NULL; + + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead) + return -EIO; + + if (unlikely(_IOC_TYPE(ioctl) != KVMIO)) + return -EINVAL; + + /* + * Wait for the vCPU to be online before handling the ioctl(), as KVM + * assumes the vCPU is reachable via vcpu_array, i.e. may dereference + * a NULL pointer if userspace invokes an ioctl() before KVM is ready. + */ + r = kvm_wait_for_vcpu_online(vcpu); + if (r) + return r; + + /* + * Let arch code handle select vCPU ioctls without holding vcpu->mutex, + * e.g. to support ioctls that can run asynchronous to vCPU execution. + */ + r = kvm_arch_vcpu_unlocked_ioctl(filp, ioctl, arg); + if (r != -ENOIOCTLCMD) + return r; + + if (mutex_lock_killable(&vcpu->mutex)) + return -EINTR; + switch (ioctl) { + case KVM_RUN: { + struct pid *oldpid; + r = -EINVAL; + if (arg) + goto out; + + /* + * Note, vcpu->pid is primarily protected by vcpu->mutex. The + * dedicated r/w lock allows other tasks, e.g. other vCPUs, to + * read vcpu->pid while this vCPU is in KVM_RUN, e.g. to yield + * directly to this vCPU + */ + oldpid = vcpu->pid; + if (unlikely(oldpid != task_pid(current))) { + /* The thread running this VCPU changed. */ + struct pid *newpid; + + r = kvm_arch_vcpu_run_pid_change(vcpu); + if (r) + break; + + newpid = get_task_pid(current, PIDTYPE_PID); + write_lock(&vcpu->pid_lock); + vcpu->pid = newpid; + write_unlock(&vcpu->pid_lock); + + put_pid(oldpid); + } + vcpu->wants_to_run = !READ_ONCE(vcpu->run->immediate_exit__unsafe); + r = kvm_arch_vcpu_ioctl_run(vcpu); + vcpu->wants_to_run = false; + + /* + * FIXME: Remove this hack once all KVM architectures + * support the generic TIF bits, i.e. a dedicated TIF_RSEQ. + */ + rseq_virt_userspace_exit(); + + trace_kvm_userspace_exit(vcpu->run->exit_reason, r); + break; + } + case KVM_GET_REGS: { + struct kvm_regs *kvm_regs; + + r = -ENOMEM; + kvm_regs = kzalloc_obj(struct kvm_regs); + if (!kvm_regs) + goto out; + r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs); + if (r) + goto out_free1; + r = -EFAULT; + if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs))) + goto out_free1; + r = 0; +out_free1: + kfree(kvm_regs); + break; + } + case KVM_SET_REGS: { + struct kvm_regs *kvm_regs; + + kvm_regs = memdup_user(argp, sizeof(*kvm_regs)); + if (IS_ERR(kvm_regs)) { + r = PTR_ERR(kvm_regs); + goto out; + } + r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs); + kfree(kvm_regs); + break; + } + case KVM_GET_SREGS: { + kvm_sregs = kzalloc_obj(struct kvm_sregs); + r = -ENOMEM; + if (!kvm_sregs) + goto out; + r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs))) + goto out; + r = 0; + break; + } + case KVM_SET_SREGS: { + kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs)); + if (IS_ERR(kvm_sregs)) { + r = PTR_ERR(kvm_sregs); + kvm_sregs = NULL; + goto out; + } + r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs); + break; + } + case KVM_GET_MP_STATE: { + struct kvm_mp_state mp_state; + + r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, &mp_state, sizeof(mp_state))) + goto out; + r = 0; + break; + } + case KVM_SET_MP_STATE: { + struct kvm_mp_state mp_state; + + r = -EFAULT; + if (copy_from_user(&mp_state, argp, sizeof(mp_state))) + goto out; + r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state); + break; + } + case KVM_TRANSLATE: { + struct kvm_translation tr; + + r = -EFAULT; + if (copy_from_user(&tr, argp, sizeof(tr))) + goto out; + r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, &tr, sizeof(tr))) + goto out; + r = 0; + break; + } + case KVM_SET_GUEST_DEBUG: { + struct kvm_guest_debug dbg; + + r = -EFAULT; + if (copy_from_user(&dbg, argp, sizeof(dbg))) + goto out; + r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg); + break; + } + case KVM_SET_SIGNAL_MASK: { + struct kvm_signal_mask __user *sigmask_arg = argp; + struct kvm_signal_mask kvm_sigmask; + sigset_t sigset, *p; + + p = NULL; + if (argp) { + r = -EFAULT; + if (copy_from_user(&kvm_sigmask, argp, + sizeof(kvm_sigmask))) + goto out; + r = -EINVAL; + if (kvm_sigmask.len != sizeof(sigset)) + goto out; + r = -EFAULT; + if (copy_from_user(&sigset, sigmask_arg->sigset, + sizeof(sigset))) + goto out; + p = &sigset; + } + r = kvm_vcpu_ioctl_set_sigmask(vcpu, p); + break; + } + case KVM_GET_FPU: { + fpu = kzalloc_obj(struct kvm_fpu); + r = -ENOMEM; + if (!fpu) + goto out; + r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu))) + goto out; + r = 0; + break; + } + case KVM_SET_FPU: { + fpu = memdup_user(argp, sizeof(*fpu)); + if (IS_ERR(fpu)) { + r = PTR_ERR(fpu); + fpu = NULL; + goto out; + } + r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu); + break; + } + case KVM_GET_STATS_FD: { + r = kvm_vcpu_ioctl_get_stats_fd(vcpu); + break; + } +#ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY + case KVM_PRE_FAULT_MEMORY: { + struct kvm_pre_fault_memory range; + + r = -EFAULT; + if (copy_from_user(&range, argp, sizeof(range))) + break; + r = kvm_vcpu_pre_fault_memory(vcpu, &range); + /* Pass back leftover range. */ + if (copy_to_user(argp, &range, sizeof(range))) + r = -EFAULT; + break; + } +#endif + default: + r = kvm_arch_vcpu_ioctl(filp, ioctl, arg); + } +out: + mutex_unlock(&vcpu->mutex); + kfree(fpu); + kfree(kvm_sregs); + return r; +} + +#ifdef CONFIG_KVM_COMPAT +static long kvm_vcpu_compat_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm_vcpu *vcpu = filp->private_data; + void __user *argp = compat_ptr(arg); + int r; + + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead) + return -EIO; + + switch (ioctl) { + case KVM_SET_SIGNAL_MASK: { + struct kvm_signal_mask __user *sigmask_arg = argp; + struct kvm_signal_mask kvm_sigmask; + sigset_t sigset; + + if (argp) { + r = -EFAULT; + if (copy_from_user(&kvm_sigmask, argp, + sizeof(kvm_sigmask))) + goto out; + r = -EINVAL; + if (kvm_sigmask.len != sizeof(compat_sigset_t)) + goto out; + r = -EFAULT; + if (get_compat_sigset(&sigset, + (compat_sigset_t __user *)sigmask_arg->sigset)) + goto out; + r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset); + } else + r = kvm_vcpu_ioctl_set_sigmask(vcpu, NULL); + break; + } + default: + r = kvm_vcpu_ioctl(filp, ioctl, arg); + } + +out: + return r; +} +#endif + +static int kvm_device_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct kvm_device *dev = filp->private_data; + + if (dev->ops->mmap) + return dev->ops->mmap(dev, vma); + + return -ENODEV; +} + +static int kvm_device_ioctl_attr(struct kvm_device *dev, + int (*accessor)(struct kvm_device *dev, + struct kvm_device_attr *attr), + unsigned long arg) +{ + struct kvm_device_attr attr; + + if (!accessor) + return -EPERM; + + if (copy_from_user(&attr, (void __user *)arg, sizeof(attr))) + return -EFAULT; + + return accessor(dev, &attr); +} + +static long kvm_device_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) +{ + struct kvm_device *dev = filp->private_data; + + if (dev->kvm->mm != current->mm || dev->kvm->vm_dead) + return -EIO; + + switch (ioctl) { + case KVM_SET_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg); + case KVM_GET_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg); + case KVM_HAS_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg); + default: + if (dev->ops->ioctl) + return dev->ops->ioctl(dev, ioctl, arg); + + return -ENOTTY; + } +} + +static int kvm_device_release(struct inode *inode, struct file *filp) +{ + struct kvm_device *dev = filp->private_data; + struct kvm *kvm = dev->kvm; + + if (dev->ops->release) { + mutex_lock(&kvm->lock); + list_del_rcu(&dev->vm_node); + synchronize_rcu(); + dev->ops->release(dev); + mutex_unlock(&kvm->lock); + } + + kvm_put_kvm(kvm); + return 0; +} + +static struct file_operations kvm_device_fops = { + .unlocked_ioctl = kvm_device_ioctl, + .release = kvm_device_release, + KVM_COMPAT(kvm_device_ioctl), + .mmap = kvm_device_mmap, +}; + +struct kvm_device *kvm_device_from_filp(struct file *filp) +{ + if (filp->f_op != &kvm_device_fops) + return NULL; + + return filp->private_data; +} + +static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = { +#ifdef CONFIG_KVM_MPIC + [KVM_DEV_TYPE_FSL_MPIC_20] = &kvm_mpic_ops, + [KVM_DEV_TYPE_FSL_MPIC_42] = &kvm_mpic_ops, +#endif +}; + +int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type) +{ + if (type >= ARRAY_SIZE(kvm_device_ops_table)) + return -ENOSPC; + + if (kvm_device_ops_table[type] != NULL) + return -EEXIST; + + kvm_device_ops_table[type] = ops; + return 0; +} + +void kvm_unregister_device_ops(u32 type) +{ + if (kvm_device_ops_table[type] != NULL) + kvm_device_ops_table[type] = NULL; +} + +static int kvm_ioctl_create_device(struct kvm *kvm, + struct kvm_create_device *cd) +{ + const struct kvm_device_ops *ops; + struct kvm_device *dev; + bool test = cd->flags & KVM_CREATE_DEVICE_TEST; + int type; + int ret; + + if (cd->type >= ARRAY_SIZE(kvm_device_ops_table)) + return -ENODEV; + + type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table)); + ops = kvm_device_ops_table[type]; + if (ops == NULL) + return -ENODEV; + + if (test) + return 0; + + dev = kzalloc_obj(*dev, GFP_KERNEL_ACCOUNT); + if (!dev) + return -ENOMEM; + + dev->ops = ops; + dev->kvm = kvm; + + mutex_lock(&kvm->lock); + ret = ops->create(dev, type); + if (ret < 0) { + mutex_unlock(&kvm->lock); + kfree(dev); + return ret; + } + list_add_rcu(&dev->vm_node, &kvm->devices); + mutex_unlock(&kvm->lock); + + if (ops->init) + ops->init(dev); + + kvm_get_kvm(kvm); + ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC); + if (ret < 0) { + kvm_put_kvm_no_destroy(kvm); + mutex_lock(&kvm->lock); + list_del_rcu(&dev->vm_node); + synchronize_rcu(); + if (ops->release) + ops->release(dev); + mutex_unlock(&kvm->lock); + if (ops->destroy) + ops->destroy(dev); + return ret; + } + + cd->fd = ret; + return 0; +} + +static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) +{ + switch (arg) { + case KVM_CAP_SYNC_MMU: + case KVM_CAP_USER_MEMORY: + case KVM_CAP_USER_MEMORY2: + case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: + case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: + case KVM_CAP_INTERNAL_ERROR_DATA: +#ifdef CONFIG_HAVE_KVM_MSI + case KVM_CAP_SIGNAL_MSI: +#endif +#ifdef CONFIG_HAVE_KVM_IRQCHIP + case KVM_CAP_IRQFD: +#endif + case KVM_CAP_IOEVENTFD_ANY_LENGTH: + case KVM_CAP_CHECK_EXTENSION_VM: + case KVM_CAP_ENABLE_CAP_VM: + case KVM_CAP_HALT_POLL: + return 1; +#ifdef CONFIG_KVM_MMIO + case KVM_CAP_COALESCED_MMIO: + return KVM_COALESCED_MMIO_PAGE_OFFSET; + case KVM_CAP_COALESCED_PIO: + return 1; +#endif +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: + return KVM_DIRTY_LOG_MANUAL_CAPS; +#endif +#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING + case KVM_CAP_IRQ_ROUTING: + return KVM_MAX_IRQ_ROUTES; +#endif +#if KVM_MAX_NR_ADDRESS_SPACES > 1 + case KVM_CAP_MULTI_ADDRESS_SPACE: + if (kvm) + return kvm_arch_nr_memslot_as_ids(kvm); + return KVM_MAX_NR_ADDRESS_SPACES; +#endif + case KVM_CAP_NR_MEMSLOTS: + return KVM_USER_MEM_SLOTS; + case KVM_CAP_DIRTY_LOG_RING: +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO + return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); +#else + return 0; +#endif + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL + return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); +#else + return 0; +#endif +#ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: +#endif + case KVM_CAP_BINARY_STATS_FD: + case KVM_CAP_SYSTEM_EVENT_DATA: + case KVM_CAP_DEVICE_CTRL: + return 1; +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + case KVM_CAP_MEMORY_ATTRIBUTES: + return kvm_supported_mem_attributes(kvm); +#endif +#ifdef CONFIG_KVM_GUEST_MEMFD + case KVM_CAP_GUEST_MEMFD: + return 1; + case KVM_CAP_GUEST_MEMFD_FLAGS: + return kvm_gmem_get_supported_flags(kvm); +#endif + default: + break; + } + return kvm_vm_ioctl_check_extension(kvm, arg); +} + +static int kvm_vm_ioctl_enable_dirty_log_ring(struct kvm *kvm, u32 size) +{ + int r; + + if (!KVM_DIRTY_LOG_PAGE_OFFSET) + return -EINVAL; + + /* the size should be power of 2 */ + if (!size || (size & (size - 1))) + return -EINVAL; + + /* Should be bigger to keep the reserved entries, or a page */ + if (size < kvm_dirty_ring_get_rsvd_entries(kvm) * + sizeof(struct kvm_dirty_gfn) || size < PAGE_SIZE) + return -EINVAL; + + if (size > KVM_DIRTY_RING_MAX_ENTRIES * + sizeof(struct kvm_dirty_gfn)) + return -E2BIG; + + /* We only allow it to set once */ + if (kvm->dirty_ring_size) + return -EINVAL; + + mutex_lock(&kvm->lock); + + if (kvm->created_vcpus) { + /* We don't allow to change this value after vcpu created */ + r = -EINVAL; + } else { + kvm->dirty_ring_size = size; + r = 0; + } + + mutex_unlock(&kvm->lock); + return r; +} + +static int kvm_vm_ioctl_reset_dirty_pages(struct kvm *kvm) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + int cleared = 0, r; + + if (!kvm->dirty_ring_size) + return -EINVAL; + + mutex_lock(&kvm->slots_lock); + + kvm_for_each_vcpu(i, vcpu, kvm) { + r = kvm_dirty_ring_reset(vcpu->kvm, &vcpu->dirty_ring, &cleared); + if (r) + break; + } + + mutex_unlock(&kvm->slots_lock); + + if (cleared) + kvm_flush_remote_tlbs(kvm); + + return cleared; +} + +int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm, + struct kvm_enable_cap *cap) +{ + return -EINVAL; +} + +bool kvm_are_all_memslots_empty(struct kvm *kvm) +{ + int i; + + lockdep_assert_held(&kvm->slots_lock); + + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { + if (!kvm_memslots_empty(__kvm_memslots(kvm, i))) + return false; + } + + return true; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_are_all_memslots_empty); + +static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, + struct kvm_enable_cap *cap) +{ + switch (cap->cap) { +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: { + u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE; + + if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE) + allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS; + + if (cap->flags || (cap->args[0] & ~allowed_options)) + return -EINVAL; + kvm->manual_dirty_log_protect = cap->args[0]; + return 0; + } +#endif + case KVM_CAP_HALT_POLL: { + if (cap->flags || cap->args[0] != (unsigned int)cap->args[0]) + return -EINVAL; + + kvm->max_halt_poll_ns = cap->args[0]; + + /* + * Ensure kvm->override_halt_poll_ns does not become visible + * before kvm->max_halt_poll_ns. + * + * Pairs with the smp_rmb() in kvm_vcpu_max_halt_poll_ns(). + */ + smp_wmb(); + kvm->override_halt_poll_ns = true; + + return 0; + } + case KVM_CAP_DIRTY_LOG_RING: + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: + if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap)) + return -EINVAL; + + return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]); + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: { + int r = -EINVAL; + + if (!IS_ENABLED(CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP) || + !kvm->dirty_ring_size || cap->flags) + return r; + + mutex_lock(&kvm->slots_lock); + + /* + * For simplicity, allow enabling ring+bitmap if and only if + * there are no memslots, e.g. to ensure all memslots allocate + * a bitmap after the capability is enabled. + */ + if (kvm_are_all_memslots_empty(kvm)) { + kvm->dirty_ring_with_bitmap = true; + r = 0; + } + + mutex_unlock(&kvm->slots_lock); + + return r; + } + default: + return kvm_vm_ioctl_enable_cap(kvm, cap); + } +} + +static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm *kvm = file->private_data; + + return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header, + &kvm_vm_stats_desc[0], &kvm->stat, + sizeof(kvm->stat), user_buffer, size, offset); +} + +static int kvm_vm_stats_release(struct inode *inode, struct file *file) +{ + struct kvm *kvm = file->private_data; + + kvm_put_kvm(kvm); + return 0; +} + +static const struct file_operations kvm_vm_stats_fops = { + .owner = THIS_MODULE, + .read = kvm_vm_stats_read, + .release = kvm_vm_stats_release, + .llseek = noop_llseek, +}; + +static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) +{ + int fd; + struct file *file; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile_fmode("kvm-vm-stats", + &kvm_vm_stats_fops, kvm, O_RDONLY, FMODE_PREAD); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + + kvm_get_kvm(kvm); + fd_install(fd, file); + + return fd; +} + +#define SANITY_CHECK_MEM_REGION_FIELD(field) \ +do { \ + BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) != \ + offsetof(struct kvm_userspace_memory_region2, field)); \ + BUILD_BUG_ON(sizeof_field(struct kvm_userspace_memory_region, field) != \ + sizeof_field(struct kvm_userspace_memory_region2, field)); \ +} while (0) + +static long kvm_vm_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm *kvm = filp->private_data; + void __user *argp = (void __user *)arg; + int r; + + if (kvm->mm != current->mm || kvm->vm_dead) + return -EIO; + switch (ioctl) { + case KVM_CREATE_VCPU: + r = kvm_vm_ioctl_create_vcpu(kvm, arg); + break; + case KVM_ENABLE_CAP: { + struct kvm_enable_cap cap; + + r = -EFAULT; + if (copy_from_user(&cap, argp, sizeof(cap))) + goto out; + r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap); + break; + } + case KVM_SET_USER_MEMORY_REGION2: + case KVM_SET_USER_MEMORY_REGION: { + struct kvm_userspace_memory_region2 mem; + unsigned long size; + + if (ioctl == KVM_SET_USER_MEMORY_REGION) { + /* + * Fields beyond struct kvm_userspace_memory_region shouldn't be + * accessed, but avoid leaking kernel memory in case of a bug. + */ + memset(&mem, 0, sizeof(mem)); + size = sizeof(struct kvm_userspace_memory_region); + } else { + size = sizeof(struct kvm_userspace_memory_region2); + } + + /* Ensure the common parts of the two structs are identical. */ + SANITY_CHECK_MEM_REGION_FIELD(slot); + SANITY_CHECK_MEM_REGION_FIELD(flags); + SANITY_CHECK_MEM_REGION_FIELD(guest_phys_addr); + SANITY_CHECK_MEM_REGION_FIELD(memory_size); + SANITY_CHECK_MEM_REGION_FIELD(userspace_addr); + + r = -EFAULT; + if (copy_from_user(&mem, argp, size)) + goto out; + + r = -EINVAL; + if (ioctl == KVM_SET_USER_MEMORY_REGION && + (mem.flags & ~KVM_SET_USER_MEMORY_REGION_V1_FLAGS)) + goto out; + + r = kvm_vm_ioctl_set_memory_region(kvm, &mem); + break; + } + case KVM_GET_DIRTY_LOG: { + struct kvm_dirty_log log; + + r = -EFAULT; + if (copy_from_user(&log, argp, sizeof(log))) + goto out; + r = kvm_vm_ioctl_get_dirty_log(kvm, &log); + break; + } +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CLEAR_DIRTY_LOG: { + struct kvm_clear_dirty_log log; + + r = -EFAULT; + if (copy_from_user(&log, argp, sizeof(log))) + goto out; + r = kvm_vm_ioctl_clear_dirty_log(kvm, &log); + break; + } +#endif +#ifdef CONFIG_KVM_MMIO + case KVM_REGISTER_COALESCED_MMIO: { + struct kvm_coalesced_mmio_zone zone; + + r = -EFAULT; + if (copy_from_user(&zone, argp, sizeof(zone))) + goto out; + r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone); + break; + } + case KVM_UNREGISTER_COALESCED_MMIO: { + struct kvm_coalesced_mmio_zone zone; + + r = -EFAULT; + if (copy_from_user(&zone, argp, sizeof(zone))) + goto out; + r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone); + break; + } +#endif + case KVM_IRQFD: { + struct kvm_irqfd data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof(data))) + goto out; + r = kvm_irqfd(kvm, &data); + break; + } + case KVM_IOEVENTFD: { + struct kvm_ioeventfd data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof(data))) + goto out; + r = kvm_ioeventfd(kvm, &data); + break; + } +#ifdef CONFIG_HAVE_KVM_MSI + case KVM_SIGNAL_MSI: { + struct kvm_msi msi; + + r = -EFAULT; + if (copy_from_user(&msi, argp, sizeof(msi))) + goto out; + r = kvm_send_userspace_msi(kvm, &msi); + break; + } +#endif +#ifdef __KVM_HAVE_IRQ_LINE + case KVM_IRQ_LINE_STATUS: + case KVM_IRQ_LINE: { + struct kvm_irq_level irq_event; + + r = -EFAULT; + if (copy_from_user(&irq_event, argp, sizeof(irq_event))) + goto out; + + r = kvm_vm_ioctl_irq_line(kvm, &irq_event, + ioctl == KVM_IRQ_LINE_STATUS); + if (r) + goto out; + + r = -EFAULT; + if (ioctl == KVM_IRQ_LINE_STATUS) { + if (copy_to_user(argp, &irq_event, sizeof(irq_event))) + goto out; + } + + r = 0; + break; + } +#endif +#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING + case KVM_SET_GSI_ROUTING: { + struct kvm_irq_routing routing; + struct kvm_irq_routing __user *urouting; + struct kvm_irq_routing_entry *entries = NULL; + + r = -EFAULT; + if (copy_from_user(&routing, argp, sizeof(routing))) + goto out; + r = -EINVAL; + if (!kvm_arch_can_set_irq_routing(kvm)) + goto out; + if (routing.nr > KVM_MAX_IRQ_ROUTES) + goto out; + if (routing.flags) + goto out; + if (routing.nr) { + urouting = argp; + entries = vmemdup_array_user(urouting->entries, + routing.nr, sizeof(*entries)); + if (IS_ERR(entries)) { + r = PTR_ERR(entries); + goto out; + } + } + r = kvm_set_irq_routing(kvm, entries, routing.nr, + routing.flags); + kvfree(entries); + break; + } +#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */ +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES + case KVM_SET_MEMORY_ATTRIBUTES: { + struct kvm_memory_attributes attrs; + + r = -EFAULT; + if (copy_from_user(&attrs, argp, sizeof(attrs))) + goto out; + + r = kvm_vm_ioctl_set_mem_attributes(kvm, &attrs); + break; + } +#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ + case KVM_CREATE_DEVICE: { + struct kvm_create_device cd; + + r = -EFAULT; + if (copy_from_user(&cd, argp, sizeof(cd))) + goto out; + + r = kvm_ioctl_create_device(kvm, &cd); + if (r) + goto out; + + r = -EFAULT; + if (copy_to_user(argp, &cd, sizeof(cd))) + goto out; + + r = 0; + break; + } + case KVM_CHECK_EXTENSION: + r = kvm_vm_ioctl_check_extension_generic(kvm, arg); + break; + case KVM_RESET_DIRTY_RINGS: + r = kvm_vm_ioctl_reset_dirty_pages(kvm); + break; + case KVM_GET_STATS_FD: + r = kvm_vm_ioctl_get_stats_fd(kvm); + break; +#ifdef CONFIG_KVM_GUEST_MEMFD + case KVM_CREATE_GUEST_MEMFD: { + struct kvm_create_guest_memfd guest_memfd; + + r = -EFAULT; + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) + goto out; + + r = kvm_gmem_create(kvm, &guest_memfd); + break; + } +#endif + default: + r = kvm_arch_vm_ioctl(filp, ioctl, arg); + } +out: + return r; +} + +#ifdef CONFIG_KVM_COMPAT +struct compat_kvm_dirty_log { + __u32 slot; + __u32 padding1; + union { + compat_uptr_t dirty_bitmap; /* one bit per page */ + __u64 padding2; + }; +}; + +struct compat_kvm_clear_dirty_log { + __u32 slot; + __u32 num_pages; + __u64 first_page; + union { + compat_uptr_t dirty_bitmap; /* one bit per page */ + __u64 padding2; + }; +}; + +long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) +{ + return -ENOTTY; +} + +static long kvm_vm_compat_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm *kvm = filp->private_data; + int r; + + if (kvm->mm != current->mm || kvm->vm_dead) + return -EIO; + + r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg); + if (r != -ENOTTY) + return r; + + switch (ioctl) { +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CLEAR_DIRTY_LOG: { + struct compat_kvm_clear_dirty_log compat_log; + struct kvm_clear_dirty_log log; + + if (copy_from_user(&compat_log, (void __user *)arg, + sizeof(compat_log))) + return -EFAULT; + log.slot = compat_log.slot; + log.num_pages = compat_log.num_pages; + log.first_page = compat_log.first_page; + log.padding2 = compat_log.padding2; + log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap); + + r = kvm_vm_ioctl_clear_dirty_log(kvm, &log); + break; + } +#endif + case KVM_GET_DIRTY_LOG: { + struct compat_kvm_dirty_log compat_log; + struct kvm_dirty_log log; + + if (copy_from_user(&compat_log, (void __user *)arg, + sizeof(compat_log))) + return -EFAULT; + log.slot = compat_log.slot; + log.padding1 = compat_log.padding1; + log.padding2 = compat_log.padding2; + log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap); + + r = kvm_vm_ioctl_get_dirty_log(kvm, &log); + break; + } + default: + r = kvm_vm_ioctl(filp, ioctl, arg); + } + return r; +} +#endif + +static struct file_operations kvm_vm_fops = { + .release = kvm_vm_release, + .unlocked_ioctl = kvm_vm_ioctl, + .llseek = noop_llseek, + KVM_COMPAT(kvm_vm_compat_ioctl), +}; + +bool file_is_kvm(struct file *file) +{ + return file && file->f_op == &kvm_vm_fops; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(file_is_kvm); + +static int kvm_dev_ioctl_create_vm(unsigned long type) +{ + char fdname[ITOA_MAX_LEN + 1]; + int r, fd; + struct kvm *kvm; + struct file *file; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + snprintf(fdname, sizeof(fdname), "%d", fd); + + kvm = kvm_create_vm(type, fdname); + if (IS_ERR(kvm)) { + r = PTR_ERR(kvm); + goto put_fd; + } + + file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR); + if (IS_ERR(file)) { + r = PTR_ERR(file); + goto put_kvm; + } + + /* + * Don't call kvm_put_kvm anymore at this point; file->f_op is + * already set, with ->release() being kvm_vm_release(). In error + * cases it will be called by the final fput(file) and will take + * care of doing kvm_put_kvm(kvm). + */ + kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm); + + fd_install(fd, file); + return fd; + +put_kvm: + kvm_put_kvm(kvm); +put_fd: + put_unused_fd(fd); + return r; +} + +static long kvm_dev_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + int r = -EINVAL; + + switch (ioctl) { + case KVM_GET_API_VERSION: + if (arg) + goto out; + r = KVM_API_VERSION; + break; + case KVM_CREATE_VM: + r = kvm_dev_ioctl_create_vm(arg); + break; + case KVM_CHECK_EXTENSION: + r = kvm_vm_ioctl_check_extension_generic(NULL, arg); + break; + case KVM_GET_VCPU_MMAP_SIZE: + if (arg) + goto out; + r = PAGE_SIZE; /* struct kvm_run */ +#ifdef CONFIG_X86 + r += PAGE_SIZE; /* pio data page */ +#endif +#ifdef CONFIG_KVM_MMIO + r += PAGE_SIZE; /* coalesced mmio ring page */ +#endif + break; + default: + return kvm_arch_dev_ioctl(filp, ioctl, arg); + } +out: + return r; +} + +static struct file_operations kvm_chardev_ops = { + .unlocked_ioctl = kvm_dev_ioctl, + .llseek = noop_llseek, + KVM_COMPAT(kvm_dev_ioctl), +}; + +static struct miscdevice kvm_dev = { + KVM_MINOR, + "kvm", + &kvm_chardev_ops, +}; + +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING +bool __ro_after_init enable_virt_at_load = true; +module_param(enable_virt_at_load, bool, 0444); +EXPORT_SYMBOL_FOR_KVM_INTERNAL(enable_virt_at_load); + +static DEFINE_PER_CPU(bool, virtualization_enabled); +static DEFINE_MUTEX(kvm_usage_lock); +static int kvm_usage_count; + +__weak void kvm_arch_shutdown(void) +{ + +} + +__weak void kvm_arch_enable_virtualization(void) +{ + +} + +__weak void kvm_arch_disable_virtualization(void) +{ + +} + +static int kvm_enable_virtualization_cpu(void) +{ + if (__this_cpu_read(virtualization_enabled)) + return 0; + + if (kvm_arch_enable_virtualization_cpu()) { + pr_info("kvm: enabling virtualization on CPU%d failed\n", + raw_smp_processor_id()); + return -EIO; + } + + __this_cpu_write(virtualization_enabled, true); + return 0; +} + +static int kvm_online_cpu(unsigned int cpu) +{ + /* + * Abort the CPU online process if hardware virtualization cannot + * be enabled. Otherwise running VMs would encounter unrecoverable + * errors when scheduled to this CPU. + */ + return kvm_enable_virtualization_cpu(); +} + +static void kvm_disable_virtualization_cpu(void *ign) +{ + if (!__this_cpu_read(virtualization_enabled)) + return; + + kvm_arch_disable_virtualization_cpu(); + + __this_cpu_write(virtualization_enabled, false); +} + +static int kvm_offline_cpu(unsigned int cpu) +{ + kvm_disable_virtualization_cpu(NULL); + return 0; +} + +static void kvm_shutdown(void *data) +{ + kvm_arch_shutdown(); + + /* + * Some flavors of hardware virtualization need to be disabled before + * transferring control to firmware (to perform shutdown/reboot), e.g. + * on x86, virtualization can block INIT interrupts, which are used by + * firmware to pull APs back under firmware control. Note, this path + * is used for both shutdown and reboot scenarios, i.e. neither name is + * 100% comprehensive. + */ + pr_info("kvm: exiting hardware virtualization\n"); + on_each_cpu(kvm_disable_virtualization_cpu, NULL, 1); +} + +static int kvm_suspend(void *data) +{ + /* + * Secondary CPUs and CPU hotplug are disabled across the suspend/resume + * callbacks, i.e. no need to acquire kvm_usage_lock to ensure the usage + * count is stable. Assert that kvm_usage_lock is not held to ensure + * the system isn't suspended while KVM is enabling hardware. Hardware + * enabling can be preempted, but the task cannot be frozen until it has + * dropped all locks (userspace tasks are frozen via a fake signal). + */ + lockdep_assert_not_held(&kvm_usage_lock); + lockdep_assert_irqs_disabled(); + + kvm_disable_virtualization_cpu(NULL); + return 0; +} + +static void kvm_resume(void *data) +{ + lockdep_assert_not_held(&kvm_usage_lock); + lockdep_assert_irqs_disabled(); + + WARN_ON_ONCE(kvm_enable_virtualization_cpu()); +} + +static const struct syscore_ops kvm_syscore_ops = { + .suspend = kvm_suspend, + .resume = kvm_resume, + .shutdown = kvm_shutdown, +}; + +static struct syscore kvm_syscore = { + .ops = &kvm_syscore_ops, +}; + +static int kvm_enable_virtualization(void) +{ + int r; + + guard(mutex)(&kvm_usage_lock); + + if (kvm_usage_count++) + return 0; + + kvm_arch_enable_virtualization(); + + r = cpuhp_setup_state(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", + kvm_online_cpu, kvm_offline_cpu); + if (r) + goto err_cpuhp; + + register_syscore(&kvm_syscore); + + /* + * Undo virtualization enabling and bail if the system is going down. + * If userspace initiated a forced reboot, e.g. reboot -f, then it's + * possible for an in-flight operation to enable virtualization after + * syscore_shutdown() is called, i.e. without kvm_shutdown() being + * invoked. Note, this relies on system_state being set _before_ + * kvm_shutdown(), e.g. to ensure either kvm_shutdown() is invoked + * or this CPU observes the impending shutdown. Which is why KVM uses + * a syscore ops hook instead of registering a dedicated reboot + * notifier (the latter runs before system_state is updated). + */ + if (system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF || + system_state == SYSTEM_RESTART) { + r = -EBUSY; + goto err_rebooting; + } + + return 0; + +err_rebooting: + unregister_syscore(&kvm_syscore); + cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); +err_cpuhp: + kvm_arch_disable_virtualization(); + --kvm_usage_count; + return r; +} + +static void kvm_disable_virtualization(void) +{ + guard(mutex)(&kvm_usage_lock); + + if (--kvm_usage_count) + return; + + unregister_syscore(&kvm_syscore); + cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); + kvm_arch_disable_virtualization(); +} + +static int kvm_init_virtualization(void) +{ + if (enable_virt_at_load) + return kvm_enable_virtualization(); + + return 0; +} + +static void kvm_uninit_virtualization(void) +{ + if (enable_virt_at_load) + kvm_disable_virtualization(); +} +#else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ +static int kvm_enable_virtualization(void) +{ + return 0; +} +static void kvm_disable_virtualization(void) +{ + +} +static int kvm_init_virtualization(void) +{ + return 0; +} + +static void kvm_uninit_virtualization(void) +{ + +} +#endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ + +static void kvm_iodevice_destructor(struct kvm_io_device *dev) +{ + if (dev->ops->destructor) + dev->ops->destructor(dev); +} + +static void kvm_io_bus_destroy(struct kvm_io_bus *bus) +{ + int i; + + for (i = 0; i < bus->dev_count; i++) { + struct kvm_io_device *pos = bus->range[i].dev; + + kvm_iodevice_destructor(pos); + } + kfree(bus); +} + +static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1, + const struct kvm_io_range *r2) +{ + gpa_t addr1 = r1->addr; + gpa_t addr2 = r2->addr; + + if (addr1 < addr2) + return -1; + + /* If r2->len == 0, match the exact address. If r2->len != 0, + * accept any overlapping write. Any order is acceptable for + * overlapping ranges, because kvm_io_bus_get_first_dev ensures + * we process all of them. + */ + if (r2->len) { + addr1 += r1->len; + addr2 += r2->len; + } + + if (addr1 > addr2) + return 1; + + return 0; +} + +static int kvm_io_bus_sort_cmp(const void *p1, const void *p2) +{ + return kvm_io_bus_cmp(p1, p2); +} + +static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus, + gpa_t addr, int len) +{ + struct kvm_io_range *range, key; + int off; + + key = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + range = bsearch(&key, bus->range, bus->dev_count, + sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp); + if (range == NULL) + return -ENOENT; + + off = range - bus->range; + + while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0) + off--; + + return off; +} + +static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus, + struct kvm_io_range *range, const void *val) +{ + int idx; + + idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len); + if (idx < 0) + return -EOPNOTSUPP; + + while (idx < bus->dev_count && + kvm_io_bus_cmp(range, &bus->range[idx]) == 0) { + if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr, + range->len, val)) + return idx; + idx++; + } + + return -EOPNOTSUPP; +} + +static struct kvm_io_bus *kvm_get_bus_srcu(struct kvm *kvm, enum kvm_bus idx) +{ + /* + * Ensure that any updates to kvm_buses[] observed by the previous vCPU + * machine instruction are also visible to the vCPU machine instruction + * that triggered this call. + */ + smp_mb__after_srcu_read_lock(); + + return srcu_dereference(kvm->buses[idx], &kvm->srcu); +} + +int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, + int len, const void *val) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + int r; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx); + if (!bus) + return -ENOMEM; + r = __kvm_io_bus_write(vcpu, bus, &range, val); + return r < 0 ? r : 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_write); + +int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, + gpa_t addr, int len, const void *val, long cookie) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx); + if (!bus) + return -ENOMEM; + + /* First try the device referenced by cookie. */ + if ((cookie >= 0) && (cookie < bus->dev_count) && + (kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0)) + if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len, + val)) + return cookie; + + /* + * cookie contained garbage; fall back to search and return the + * correct cookie value. + */ + return __kvm_io_bus_write(vcpu, bus, &range, val); +} + +static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus, + struct kvm_io_range *range, void *val) +{ + int idx; + + idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len); + if (idx < 0) + return -EOPNOTSUPP; + + while (idx < bus->dev_count && + kvm_io_bus_cmp(range, &bus->range[idx]) == 0) { + if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr, + range->len, val)) + return idx; + idx++; + } + + return -EOPNOTSUPP; +} + +int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, + int len, void *val) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + int r; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx); + if (!bus) + return -ENOMEM; + r = __kvm_io_bus_read(vcpu, bus, &range, val); + return r < 0 ? r : 0; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_read); + +static void __free_bus(struct rcu_head *rcu) +{ + struct kvm_io_bus *bus = container_of(rcu, struct kvm_io_bus, rcu); + + kfree(bus); +} + +int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, + int len, struct kvm_io_device *dev) +{ + int i; + struct kvm_io_bus *new_bus, *bus; + struct kvm_io_range range; + + lockdep_assert_held(&kvm->slots_lock); + + bus = kvm_get_bus(kvm, bus_idx); + if (!bus) + return -ENOMEM; + + /* exclude ioeventfd which is limited by maximum fd */ + if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1) + return -ENOSPC; + + new_bus = kmalloc_flex(*bus, range, bus->dev_count + 1, + GFP_KERNEL_ACCOUNT); + if (!new_bus) + return -ENOMEM; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + .dev = dev, + }; + + for (i = 0; i < bus->dev_count; i++) + if (kvm_io_bus_cmp(&bus->range[i], &range) > 0) + break; + + memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range)); + new_bus->dev_count++; + new_bus->range[i] = range; + memcpy(new_bus->range + i + 1, bus->range + i, + (bus->dev_count - i) * sizeof(struct kvm_io_range)); + rcu_assign_pointer(kvm->buses[bus_idx], new_bus); + call_srcu(&kvm->srcu, &bus->rcu, __free_bus); + + return 0; +} + +int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, + struct kvm_io_device *dev) +{ + int i; + struct kvm_io_bus *new_bus, *bus; + + lockdep_assert_held(&kvm->slots_lock); + + bus = kvm_get_bus(kvm, bus_idx); + if (!bus) + return 0; + + for (i = 0; i < bus->dev_count; i++) { + if (bus->range[i].dev == dev) { + break; + } + } + + if (i == bus->dev_count) + return 0; + + new_bus = kmalloc_flex(*bus, range, bus->dev_count - 1, + GFP_KERNEL_ACCOUNT); + if (new_bus) { + memcpy(new_bus, bus, struct_size(bus, range, i)); + new_bus->dev_count--; + memcpy(new_bus->range + i, bus->range + i + 1, + flex_array_size(new_bus, range, new_bus->dev_count - i)); + } + + rcu_assign_pointer(kvm->buses[bus_idx], new_bus); + synchronize_srcu_expedited(&kvm->srcu); + + /* + * If NULL bus is installed, destroy the old bus, including all the + * attached devices. Otherwise, destroy the caller's device only. + */ + if (!new_bus) { + pr_err("kvm: failed to shrink bus, removing it completely\n"); + kvm_io_bus_destroy(bus); + return -ENOMEM; + } + + kvm_iodevice_destructor(dev); + kfree(bus); + return 0; +} + +struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx, + gpa_t addr) +{ + struct kvm_io_bus *bus; + int dev_idx, srcu_idx; + struct kvm_io_device *iodev = NULL; + + srcu_idx = srcu_read_lock(&kvm->srcu); + + bus = kvm_get_bus_srcu(kvm, bus_idx); + if (!bus) + goto out_unlock; + + dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1); + if (dev_idx < 0) + goto out_unlock; + + iodev = bus->range[dev_idx].dev; + +out_unlock: + srcu_read_unlock(&kvm->srcu, srcu_idx); + + return iodev; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_get_dev); + +static int kvm_debugfs_open(struct inode *inode, struct file *file, + int (*get)(void *, u64 *), int (*set)(void *, u64), + const char *fmt) +{ + int ret; + struct kvm_stat_data *stat_data = inode->i_private; + + /* + * The debugfs files are a reference to the kvm struct which + * is still valid when kvm_destroy_vm is called. kvm_get_kvm_safe + * avoids the race between open and the removal of the debugfs directory. + */ + if (!kvm_get_kvm_safe(stat_data->kvm)) + return -ENOENT; + + ret = simple_attr_open(inode, file, get, + kvm_stats_debugfs_mode(stat_data->desc) & 0222 + ? set : NULL, fmt); + if (ret) + kvm_put_kvm(stat_data->kvm); + + return ret; +} + +static int kvm_debugfs_release(struct inode *inode, struct file *file) +{ + struct kvm_stat_data *stat_data = inode->i_private; + + simple_attr_release(inode, file); + kvm_put_kvm(stat_data->kvm); + + return 0; +} + +static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val) +{ + *val = *(u64 *)((void *)(&kvm->stat) + offset); + + return 0; +} + +static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset) +{ + *(u64 *)((void *)(&kvm->stat) + offset) = 0; + + return 0; +} + +static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + *val = 0; + + kvm_for_each_vcpu(i, vcpu, kvm) + *val += *(u64 *)((void *)(&vcpu->stat) + offset); + + return 0; +} + +static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + kvm_for_each_vcpu(i, vcpu, kvm) + *(u64 *)((void *)(&vcpu->stat) + offset) = 0; + + return 0; +} + +static int kvm_stat_data_get(void *data, u64 *val) +{ + int r = -EFAULT; + struct kvm_stat_data *stat_data = data; + + switch (stat_data->kind) { + case KVM_STAT_VM: + r = kvm_get_stat_per_vm(stat_data->kvm, + stat_data->desc->offset, val); + break; + case KVM_STAT_VCPU: + r = kvm_get_stat_per_vcpu(stat_data->kvm, + stat_data->desc->offset, val); + break; + } + + return r; +} + +static int kvm_stat_data_clear(void *data, u64 val) +{ + int r = -EFAULT; + struct kvm_stat_data *stat_data = data; + + if (val) + return -EINVAL; + + switch (stat_data->kind) { + case KVM_STAT_VM: + r = kvm_clear_stat_per_vm(stat_data->kvm, + stat_data->desc->offset); + break; + case KVM_STAT_VCPU: + r = kvm_clear_stat_per_vcpu(stat_data->kvm, + stat_data->desc->offset); + break; + } + + return r; +} + +static int kvm_stat_data_open(struct inode *inode, struct file *file) +{ + __simple_attr_check_format("%llu\n", 0ull); + return kvm_debugfs_open(inode, file, kvm_stat_data_get, + kvm_stat_data_clear, "%llu\n"); +} + +static const struct file_operations stat_fops_per_vm = { + .owner = THIS_MODULE, + .open = kvm_stat_data_open, + .release = kvm_debugfs_release, + .read = simple_attr_read, + .write = simple_attr_write, +}; + +static int vm_stat_get(void *_offset, u64 *val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + u64 tmp_val; + + *val = 0; + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_get_stat_per_vm(kvm, offset, &tmp_val); + *val += tmp_val; + } + mutex_unlock(&kvm_lock); + return 0; +} + +static int vm_stat_clear(void *_offset, u64 val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + + if (val) + return -EINVAL; + + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_clear_stat_per_vm(kvm, offset); + } + mutex_unlock(&kvm_lock); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n"); +DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n"); + +static int vcpu_stat_get(void *_offset, u64 *val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + u64 tmp_val; + + *val = 0; + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_get_stat_per_vcpu(kvm, offset, &tmp_val); + *val += tmp_val; + } + mutex_unlock(&kvm_lock); + return 0; +} + +static int vcpu_stat_clear(void *_offset, u64 val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + + if (val) + return -EINVAL; + + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_clear_stat_per_vcpu(kvm, offset); + } + mutex_unlock(&kvm_lock); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear, + "%llu\n"); +DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n"); + +static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) +{ + struct kobj_uevent_env *env; + unsigned long long created, active; + + if (!kvm_dev.this_device || !kvm) + return; + + mutex_lock(&kvm_lock); + if (type == KVM_EVENT_CREATE_VM) { + kvm_createvm_count++; + kvm_active_vms++; + } else if (type == KVM_EVENT_DESTROY_VM) { + kvm_active_vms--; + } + created = kvm_createvm_count; + active = kvm_active_vms; + mutex_unlock(&kvm_lock); + + env = kzalloc_obj(*env); + if (!env) + return; + + add_uevent_var(env, "CREATED=%llu", created); + add_uevent_var(env, "COUNT=%llu", active); + + if (type == KVM_EVENT_CREATE_VM) { + add_uevent_var(env, "EVENT=create"); + kvm->userspace_pid = task_pid_nr(current); + } else if (type == KVM_EVENT_DESTROY_VM) { + add_uevent_var(env, "EVENT=destroy"); + } + add_uevent_var(env, "PID=%d", kvm->userspace_pid); + + if (!IS_ERR(kvm->debugfs_dentry)) { + char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL); + + if (p) { + tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX); + if (!IS_ERR(tmp)) + add_uevent_var(env, "STATS_PATH=%s", tmp); + kfree(p); + } + } + /* no need for checks, since we are adding at most only 5 keys */ + env->envp[env->envp_idx++] = NULL; + kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp); + kfree(env); +} + +static void kvm_init_debug(void) +{ + const struct file_operations *fops; + const struct kvm_stats_desc *pdesc; + int i; + + kvm_debugfs_dir = debugfs_create_dir("kvm", NULL); + + for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) { + pdesc = &kvm_vm_stats_desc[i]; + if (kvm_stats_debugfs_mode(pdesc) & 0222) + fops = &vm_stat_fops; + else + fops = &vm_stat_readonly_fops; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm_debugfs_dir, + (void *)(long)pdesc->offset, fops); + } + + for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) { + pdesc = &kvm_vcpu_stats_desc[i]; + if (kvm_stats_debugfs_mode(pdesc) & 0222) + fops = &vcpu_stat_fops; + else + fops = &vcpu_stat_readonly_fops; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm_debugfs_dir, + (void *)(long)pdesc->offset, fops); + } +} + +static inline +struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn) +{ + return container_of(pn, struct kvm_vcpu, preempt_notifier); +} + +static void kvm_sched_in(struct preempt_notifier *pn, int cpu) +{ + struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); + + WRITE_ONCE(vcpu->preempted, false); + WRITE_ONCE(vcpu->ready, false); + + __this_cpu_write(kvm_running_vcpu, vcpu); + kvm_arch_vcpu_load(vcpu, cpu); + + WRITE_ONCE(vcpu->scheduled_out, false); +} + +static void kvm_sched_out(struct preempt_notifier *pn, + struct task_struct *next) +{ + struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); + + WRITE_ONCE(vcpu->scheduled_out, true); + + if (task_is_runnable(current) && vcpu->wants_to_run) { + WRITE_ONCE(vcpu->preempted, true); + WRITE_ONCE(vcpu->ready, true); + } + kvm_arch_vcpu_put(vcpu); + __this_cpu_write(kvm_running_vcpu, NULL); +} + +/** + * kvm_get_running_vcpu - get the vcpu running on the current CPU. + * + * We can disable preemption locally around accessing the per-CPU variable, + * and use the resolved vcpu pointer after enabling preemption again, + * because even if the current thread is migrated to another CPU, reading + * the per-CPU value later will give us the same value as we update the + * per-CPU variable in the preempt notifier handlers. + */ +struct kvm_vcpu *kvm_get_running_vcpu(void) +{ + struct kvm_vcpu *vcpu; + + preempt_disable(); + vcpu = __this_cpu_read(kvm_running_vcpu); + preempt_enable(); + + return vcpu; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_get_running_vcpu); + +/** + * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus. + */ +struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void) +{ + return &kvm_running_vcpu; +} + +#ifdef CONFIG_GUEST_PERF_EVENTS +static unsigned int kvm_guest_state(void) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + unsigned int state; + + if (!kvm_arch_pmi_in_guest(vcpu)) + return 0; + + state = PERF_GUEST_ACTIVE; + if (!kvm_arch_vcpu_in_kernel(vcpu)) + state |= PERF_GUEST_USER; + + return state; +} + +static unsigned long kvm_guest_get_ip(void) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + + /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */ + if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu))) + return 0; + + return kvm_arch_vcpu_get_ip(vcpu); +} + +static struct perf_guest_info_callbacks kvm_guest_cbs = { + .state = kvm_guest_state, + .get_ip = kvm_guest_get_ip, + .handle_intel_pt_intr = NULL, + .handle_mediated_pmi = NULL, +}; + +void __kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void), + void (*mediated_pmi_handler)(void)) +{ + kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler; + kvm_guest_cbs.handle_mediated_pmi = mediated_pmi_handler; + + perf_register_guest_info_callbacks(&kvm_guest_cbs); +} +void kvm_unregister_perf_callbacks(void) +{ + perf_unregister_guest_info_callbacks(&kvm_guest_cbs); +} +#endif + +int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) +{ + int r; + int cpu; + + /* A kmem cache lets us meet the alignment requirements of fx_save. */ + if (!vcpu_align) + vcpu_align = __alignof__(struct kvm_vcpu); + kvm_vcpu_cache = + kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align, + SLAB_ACCOUNT, + offsetof(struct kvm_vcpu, arch), + offsetofend(struct kvm_vcpu, stats_id) + - offsetof(struct kvm_vcpu, arch), + NULL); + if (!kvm_vcpu_cache) + return -ENOMEM; + + for_each_possible_cpu(cpu) { + if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu), + GFP_KERNEL, cpu_to_node(cpu))) { + r = -ENOMEM; + goto err_cpu_kick_mask; + } + } + + r = kvm_irqfd_init(); + if (r) + goto err_irqfd; + + r = kvm_async_pf_init(); + if (r) + goto err_async_pf; + + kvm_chardev_ops.owner = module; + kvm_vm_fops.owner = module; + kvm_vcpu_fops.owner = module; + kvm_device_fops.owner = module; + + kvm_preempt_ops.sched_in = kvm_sched_in; + kvm_preempt_ops.sched_out = kvm_sched_out; + + kvm_init_debug(); + + r = kvm_vfio_ops_init(); + if (WARN_ON_ONCE(r)) + goto err_vfio; + + r = kvm_gmem_init(module); + if (r) + goto err_gmem; + + r = kvm_init_virtualization(); + if (r) + goto err_virt; + + /* + * Registration _must_ be the very last thing done, as this exposes + * /dev/kvm to userspace, i.e. all infrastructure must be setup! + */ + r = misc_register(&kvm_dev); + if (r) { + pr_err("kvm: misc device register failed\n"); + goto err_register; + } + + return 0; + +err_register: + kvm_uninit_virtualization(); +err_virt: + kvm_gmem_exit(); +err_gmem: + kvm_vfio_ops_exit(); +err_vfio: + kvm_async_pf_deinit(); +err_async_pf: + kvm_irqfd_exit(); +err_irqfd: +err_cpu_kick_mask: + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); + kmem_cache_destroy(kvm_vcpu_cache); + return r; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_init); + +void kvm_exit(void) +{ + int cpu; + + /* + * Note, unregistering /dev/kvm doesn't strictly need to come first, + * fops_get(), a.k.a. try_module_get(), prevents acquiring references + * to KVM while the module is being stopped. + */ + misc_deregister(&kvm_dev); + + kvm_uninit_virtualization(); + + debugfs_remove_recursive(kvm_debugfs_dir); + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); + kmem_cache_destroy(kvm_vcpu_cache); + kvm_gmem_exit(); + kvm_vfio_ops_exit(); + kvm_async_pf_deinit(); + kvm_irqfd_exit(); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_exit); diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h new file mode 100644 index 000000000..7510ca915 --- /dev/null +++ b/virt/kvm/kvm_mm.h @@ -0,0 +1,100 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __KVM_MM_H__ +#define __KVM_MM_H__ 1 + +#include <linux/kvm.h> +#include <linux/kvm_types.h> + +/* + * Architectures can choose whether to use an rwlock or spinlock + * for the mmu_lock. These macros, for use in common code + * only, avoids using #ifdefs in places that must deal with + * multiple architectures. + */ + +#ifdef KVM_HAVE_MMU_RWLOCK +#define KVM_MMU_LOCK_INIT(kvm) rwlock_init(&(kvm)->mmu_lock) +#define KVM_MMU_LOCK(kvm) write_lock(&(kvm)->mmu_lock) +#define KVM_MMU_UNLOCK(kvm) write_unlock(&(kvm)->mmu_lock) +#else +#define KVM_MMU_LOCK_INIT(kvm) spin_lock_init(&(kvm)->mmu_lock) +#define KVM_MMU_LOCK(kvm) spin_lock(&(kvm)->mmu_lock) +#define KVM_MMU_UNLOCK(kvm) spin_unlock(&(kvm)->mmu_lock) +#endif /* KVM_HAVE_MMU_RWLOCK */ + + +struct kvm_follow_pfn { + const struct kvm_memory_slot *slot; + const gfn_t gfn; + + unsigned long hva; + + /* FOLL_* flags modifying lookup behavior, e.g. FOLL_WRITE. */ + unsigned int flags; + + /* + * Pin the page (effectively FOLL_PIN, which is an mm/ internal flag). + * The page *must* be pinned if KVM will write to the page via a kernel + * mapping, e.g. via kmap(), mremap(), etc. + */ + bool pin; + + /* + * If non-NULL, try to get a writable mapping even for a read fault. + * Set to true if a writable mapping was obtained. + */ + bool *map_writable; + + /* + * Optional output. Set to a valid "struct page" if the returned pfn + * is for a refcounted or pinned struct page, NULL if the returned pfn + * has no struct page or if the struct page is not being refcounted + * (e.g. tail pages of non-compound higher order allocations from + * IO/PFNMAP mappings). + */ + struct page **refcounted_page; +}; + +kvm_pfn_t hva_to_pfn(struct kvm_follow_pfn *kfp); + +#ifdef CONFIG_HAVE_KVM_PFNCACHE +void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, + unsigned long start, + unsigned long end); +#else +static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, + unsigned long start, + unsigned long end) +{ +} +#endif /* HAVE_KVM_PFNCACHE */ + +#ifdef CONFIG_KVM_GUEST_MEMFD +int kvm_gmem_init(struct module *module); +void kvm_gmem_exit(void); +int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args); +int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int fd, uoff_t offset); +void kvm_gmem_unbind(struct kvm_memory_slot *slot); +#else +static inline int kvm_gmem_init(struct module *module) +{ + return 0; +} +static inline void kvm_gmem_exit(void) {}; +static inline int kvm_gmem_bind(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned int fd, uoff_t offset) +{ + WARN_ON_ONCE(1); + return -EIO; +} + +static inline void kvm_gmem_unbind(struct kvm_memory_slot *slot) +{ + WARN_ON_ONCE(1); +} +#endif /* CONFIG_KVM_GUEST_MEMFD */ + +#endif /* __KVM_MM_H__ */ diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c new file mode 100644 index 000000000..728d2c1b4 --- /dev/null +++ b/virt/kvm/pfncache.c @@ -0,0 +1,484 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel-based Virtual Machine driver for Linux + * + * This module enables kernel and guest-mode vCPU access to guest physical + * memory with suitable invalidation mechanisms. + * + * Copyright © 2021 Amazon.com, Inc. or its affiliates. + * + * Authors: + * David Woodhouse <dwmw2@infradead.org> + */ + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/errno.h> + +#include "kvm_mm.h" + +/* + * MMU notifier 'invalidate_range_start' hook. + */ +void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, unsigned long start, + unsigned long end) +{ + struct gfn_to_pfn_cache *gpc; + + spin_lock(&kvm->gpc_lock); + list_for_each_entry(gpc, &kvm->gpc_list, list) { + read_lock_irq(&gpc->lock); + + /* Only a single page so no need to care about length */ + if (gpc->valid && !is_error_noslot_pfn(gpc->pfn) && + gpc->uhva >= start && gpc->uhva < end) { + read_unlock_irq(&gpc->lock); + + /* + * There is a small window here where the cache could + * be modified, and invalidation would no longer be + * necessary. Hence check again whether invalidation + * is still necessary once the write lock has been + * acquired. + */ + + write_lock_irq(&gpc->lock); + if (gpc->valid && !is_error_noslot_pfn(gpc->pfn) && + gpc->uhva >= start && gpc->uhva < end) + gpc->valid = false; + write_unlock_irq(&gpc->lock); + continue; + } + + read_unlock_irq(&gpc->lock); + } + spin_unlock(&kvm->gpc_lock); +} + +static bool kvm_gpc_is_valid_len(gpa_t gpa, unsigned long uhva, + unsigned long len) +{ + unsigned long offset = kvm_is_error_gpa(gpa) ? offset_in_page(uhva) : + offset_in_page(gpa); + + /* + * The cached access must fit within a single page. The 'len' argument + * to activate() and refresh() exists only to enforce that. + */ + return offset + len <= PAGE_SIZE; +} + +bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(gpc->kvm); + + if (!gpc->active) + return false; + + /* + * If the page was cached from a memslot, make sure the memslots have + * not been re-configured. + */ + if (!kvm_is_error_gpa(gpc->gpa) && gpc->generation != slots->generation) + return false; + + if (kvm_is_error_hva(gpc->uhva)) + return false; + + if (!kvm_gpc_is_valid_len(gpc->gpa, gpc->uhva, len)) + return false; + + if (!gpc->valid) + return false; + + return true; +} + +static void *gpc_map(kvm_pfn_t pfn) +{ + if (pfn_valid(pfn)) + return kmap(pfn_to_page(pfn)); + +#ifdef CONFIG_HAS_IOMEM + return memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB); +#else + return NULL; +#endif +} + +static void gpc_unmap(kvm_pfn_t pfn, void *khva) +{ + /* Unmap the old pfn/page if it was mapped before. */ + if (is_error_noslot_pfn(pfn) || !khva) + return; + + if (pfn_valid(pfn)) { + kunmap(pfn_to_page(pfn)); + return; + } + +#ifdef CONFIG_HAS_IOMEM + memunmap(khva); +#endif +} + +static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_seq) +{ + /* + * mn_active_invalidate_count acts for all intents and purposes + * like mmu_invalidate_in_progress here; but the latter cannot + * be used here because the invalidation of caches in the + * mmu_notifier event occurs _before_ mmu_invalidate_in_progress + * is elevated. + * + * Note, it does not matter that mn_active_invalidate_count + * is not protected by gpc->lock. It is guaranteed to + * be elevated before the mmu_notifier acquires gpc->lock, and + * isn't dropped until after mmu_invalidate_seq is updated. + */ + if (kvm->mn_active_invalidate_count) + return true; + + /* + * Ensure mn_active_invalidate_count is read before + * mmu_invalidate_seq. This pairs with the smp_wmb() in + * mmu_notifier_invalidate_range_end() to guarantee either the + * old (non-zero) value of mn_active_invalidate_count or the + * new (incremented) value of mmu_invalidate_seq is observed. + */ + smp_rmb(); + return kvm->mmu_invalidate_seq != mmu_seq; +} + +static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) +{ + /* Note, the new page offset may be different than the old! */ + void *old_khva = (void *)PAGE_ALIGN_DOWN((uintptr_t)gpc->khva); + kvm_pfn_t new_pfn = KVM_PFN_ERR_FAULT; + void *new_khva = NULL; + unsigned long mmu_seq; + struct page *page; + + struct kvm_follow_pfn kfp = { + .slot = gpc->memslot, + .gfn = gpa_to_gfn(gpc->gpa), + .flags = FOLL_WRITE, + .hva = gpc->uhva, + .refcounted_page = &page, + }; + + lockdep_assert_held(&gpc->refresh_lock); + + lockdep_assert_held_write(&gpc->lock); + + /* + * Invalidate the cache prior to dropping gpc->lock, the gpa=>uhva + * assets have already been updated and so a concurrent check() from a + * different task may not fail the gpa/uhva/generation checks. + */ + gpc->valid = false; + + do { + mmu_seq = gpc->kvm->mmu_invalidate_seq; + smp_rmb(); + + write_unlock_irq(&gpc->lock); + + /* + * If the previous iteration "failed" due to an mmu_notifier + * event, release the pfn and unmap the kernel virtual address + * from the previous attempt. Unmapping might sleep, so this + * needs to be done after dropping the lock. Opportunistically + * check for resched while the lock isn't held. + */ + if (new_pfn != KVM_PFN_ERR_FAULT) { + /* + * Keep the mapping if the previous iteration reused + * the existing mapping and didn't create a new one. + */ + if (new_khva != old_khva) + gpc_unmap(new_pfn, new_khva); + + kvm_release_page_unused(page); + + cond_resched(); + } + + new_pfn = hva_to_pfn(&kfp); + if (is_error_noslot_pfn(new_pfn)) + goto out_error; + + /* + * Obtain a new kernel mapping if KVM itself will access the + * pfn. Note, kmap() and memremap() can both sleep, so this + * too must be done outside of gpc->lock! + */ + if (new_pfn == gpc->pfn) + new_khva = old_khva; + else + new_khva = gpc_map(new_pfn); + + if (!new_khva) { + kvm_release_page_unused(page); + goto out_error; + } + + write_lock_irq(&gpc->lock); + + /* + * Other tasks must wait for _this_ refresh to complete before + * attempting to refresh. + */ + WARN_ON_ONCE(gpc->valid); + } while (mmu_notifier_retry_cache(gpc->kvm, mmu_seq)); + + gpc->valid = true; + gpc->pfn = new_pfn; + gpc->khva = new_khva + offset_in_page(gpc->uhva); + + /* + * Put the reference to the _new_ page. The page is now tracked by the + * cache and can be safely migrated, swapped, etc... as the cache will + * invalidate any mappings in response to relevant mmu_notifier events. + */ + kvm_release_page_clean(page); + + return 0; + +out_error: + write_lock_irq(&gpc->lock); + + return -EFAULT; +} + +static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long uhva) +{ + unsigned long page_offset; + bool unmap_old = false; + unsigned long old_uhva; + kvm_pfn_t old_pfn; + bool hva_change = false; + void *old_khva; + int ret; + + /* Either gpa or uhva must be valid, but not both */ + if (WARN_ON_ONCE(kvm_is_error_gpa(gpa) == kvm_is_error_hva(uhva))) + return -EINVAL; + + lockdep_assert_held(&gpc->refresh_lock); + + write_lock_irq(&gpc->lock); + + if (!gpc->active) { + ret = -EINVAL; + goto out_unlock; + } + + old_pfn = gpc->pfn; + old_khva = (void *)PAGE_ALIGN_DOWN((uintptr_t)gpc->khva); + old_uhva = PAGE_ALIGN_DOWN(gpc->uhva); + + if (kvm_is_error_gpa(gpa)) { + page_offset = offset_in_page(uhva); + + gpc->gpa = INVALID_GPA; + gpc->memslot = NULL; + gpc->uhva = PAGE_ALIGN_DOWN(uhva); + + if (gpc->uhva != old_uhva) + hva_change = true; + } else { + struct kvm_memslots *slots = kvm_memslots(gpc->kvm); + + page_offset = offset_in_page(gpa); + + if (gpc->gpa != gpa || gpc->generation != slots->generation || + kvm_is_error_hva(gpc->uhva)) { + gfn_t gfn = gpa_to_gfn(gpa); + + gpc->gpa = gpa; + gpc->generation = slots->generation; + gpc->memslot = __gfn_to_memslot(slots, gfn); + gpc->uhva = gfn_to_hva_memslot(gpc->memslot, gfn); + + if (kvm_is_error_hva(gpc->uhva)) { + ret = -EFAULT; + goto out; + } + + /* + * Even if the GPA and/or the memslot generation changed, the + * HVA may still be the same. + */ + if (gpc->uhva != old_uhva) + hva_change = true; + } else { + gpc->uhva = old_uhva; + } + } + + /* Note: the offset must be correct before calling hva_to_pfn_retry() */ + gpc->uhva += page_offset; + + /* + * If the userspace HVA changed or the PFN was already invalid, + * drop the lock and do the HVA to PFN lookup again. + */ + if (!gpc->valid || hva_change) { + ret = hva_to_pfn_retry(gpc); + } else { + /* + * If the HVA→PFN mapping was already valid, don't unmap it. + * But do update gpc->khva because the offset within the page + * may have changed. + */ + gpc->khva = old_khva + page_offset; + ret = 0; + goto out_unlock; + } + + out: + /* + * Invalidate the cache and purge the pfn/khva if the refresh failed. + * Some/all of the uhva, gpa, and memslot generation info may still be + * valid, leave it as is. + */ + if (ret) { + gpc->valid = false; + gpc->pfn = KVM_PFN_ERR_FAULT; + gpc->khva = NULL; + } + + /* Detect a pfn change before dropping the lock! */ + unmap_old = (old_pfn != gpc->pfn); + +out_unlock: + write_unlock_irq(&gpc->lock); + + if (unmap_old) + gpc_unmap(old_pfn, old_khva); + + return ret; +} + +int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, unsigned long len) +{ + unsigned long uhva; + + guard(mutex)(&gpc->refresh_lock); + + if (!kvm_gpc_is_valid_len(gpc->gpa, gpc->uhva, len)) + return -EINVAL; + + /* + * If the GPA is valid then ignore the HVA, as a cache can be GPA-based + * or HVA-based, not both. For GPA-based caches, the HVA will be + * recomputed during refresh if necessary. + */ + uhva = kvm_is_error_gpa(gpc->gpa) ? gpc->uhva : KVM_HVA_ERR_BAD; + + return __kvm_gpc_refresh(gpc, gpc->gpa, uhva); +} + +void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct kvm *kvm) +{ + rwlock_init(&gpc->lock); + mutex_init(&gpc->refresh_lock); + + gpc->kvm = kvm; + gpc->pfn = KVM_PFN_ERR_FAULT; + gpc->gpa = INVALID_GPA; + gpc->uhva = KVM_HVA_ERR_BAD; + gpc->active = gpc->valid = false; +} + +static int __kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long uhva, + unsigned long len) +{ + struct kvm *kvm = gpc->kvm; + + if (!kvm_gpc_is_valid_len(gpa, uhva, len)) + return -EINVAL; + + guard(mutex)(&gpc->refresh_lock); + + if (!gpc->active) { + if (KVM_BUG_ON(gpc->valid, kvm)) + return -EIO; + + spin_lock(&kvm->gpc_lock); + list_add(&gpc->list, &kvm->gpc_list); + spin_unlock(&kvm->gpc_lock); + + /* + * Activate the cache after adding it to the list, a concurrent + * refresh must not establish a mapping until the cache is + * reachable by mmu_notifier events. + */ + write_lock_irq(&gpc->lock); + gpc->active = true; + write_unlock_irq(&gpc->lock); + } + return __kvm_gpc_refresh(gpc, gpa, uhva); +} + +int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len) +{ + /* + * Explicitly disallow INVALID_GPA so that the magic value can be used + * by KVM to differentiate between GPA-based and HVA-based caches. + */ + if (WARN_ON_ONCE(kvm_is_error_gpa(gpa))) + return -EINVAL; + + return __kvm_gpc_activate(gpc, gpa, KVM_HVA_ERR_BAD, len); +} + +int kvm_gpc_activate_hva(struct gfn_to_pfn_cache *gpc, unsigned long uhva, unsigned long len) +{ + if (!access_ok((void __user *)uhva, len)) + return -EINVAL; + + return __kvm_gpc_activate(gpc, INVALID_GPA, uhva, len); +} + +void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc) +{ + struct kvm *kvm = gpc->kvm; + kvm_pfn_t old_pfn; + void *old_khva; + + guard(mutex)(&gpc->refresh_lock); + + if (gpc->active) { + /* + * Deactivate the cache before removing it from the list, KVM + * must stall mmu_notifier events until all users go away, i.e. + * until gpc->lock is dropped and refresh is guaranteed to fail. + */ + write_lock_irq(&gpc->lock); + gpc->active = false; + gpc->valid = false; + + /* + * Leave the GPA => uHVA cache intact, it's protected by the + * memslot generation. The PFN lookup needs to be redone every + * time as mmu_notifier protection is lost when the cache is + * removed from the VM's gpc_list. + */ + old_khva = gpc->khva - offset_in_page(gpc->khva); + gpc->khva = NULL; + + old_pfn = gpc->pfn; + gpc->pfn = KVM_PFN_ERR_FAULT; + write_unlock_irq(&gpc->lock); + + spin_lock(&kvm->gpc_lock); + list_del(&gpc->list); + spin_unlock(&kvm->gpc_lock); + + gpc_unmap(old_pfn, old_khva); + } +} diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c new file mode 100644 index 000000000..6cdc4e9a3 --- /dev/null +++ b/virt/kvm/vfio.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VFIO-KVM bridge pseudo device + * + * Copyright (C) 2013 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + */ + +#include <linux/errno.h> +#include <linux/file.h> +#include <linux/kvm_host.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/vfio.h> +#include "vfio.h" + +#ifdef CONFIG_SPAPR_TCE_IOMMU +#include <asm/kvm_ppc.h> +#endif + +struct kvm_vfio_file { + struct list_head node; + struct file *file; +#ifdef CONFIG_SPAPR_TCE_IOMMU + struct iommu_group *iommu_group; +#endif +}; + +struct kvm_vfio { + struct list_head file_list; + struct mutex lock; + bool noncoherent; +}; + +static void kvm_vfio_file_set_kvm(struct file *file, struct kvm *kvm) +{ + void (*fn)(struct file *file, struct kvm *kvm); + + fn = symbol_get(vfio_file_set_kvm); + if (!fn) + return; + + fn(file, kvm); + + symbol_put(vfio_file_set_kvm); +} + +static bool kvm_vfio_file_enforced_coherent(struct file *file) +{ + bool (*fn)(struct file *file); + bool ret; + + fn = symbol_get(vfio_file_enforced_coherent); + if (!fn) + return false; + + ret = fn(file); + + symbol_put(vfio_file_enforced_coherent); + + return ret; +} + +static bool kvm_vfio_file_is_valid(struct file *file) +{ + bool (*fn)(struct file *file); + bool ret; + + fn = symbol_get(vfio_file_is_valid); + if (!fn) + return false; + + ret = fn(file); + + symbol_put(vfio_file_is_valid); + + return ret; +} + +#ifdef CONFIG_SPAPR_TCE_IOMMU +static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file) +{ + struct iommu_group *(*fn)(struct file *file); + struct iommu_group *ret; + + fn = symbol_get(vfio_file_iommu_group); + if (!fn) + return NULL; + + ret = fn(file); + + symbol_put(vfio_file_iommu_group); + + return ret; +} + +static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm, + struct kvm_vfio_file *kvf) +{ + if (WARN_ON_ONCE(!kvf->iommu_group)) + return; + + kvm_spapr_tce_release_iommu_group(kvm, kvf->iommu_group); + iommu_group_put(kvf->iommu_group); + kvf->iommu_group = NULL; +} +#endif + +/* + * Groups/devices can use the same or different IOMMU domains. If the same + * then adding a new group/device may change the coherency of groups/devices + * we've previously been told about. We don't want to care about any of + * that so we retest each group/device and bail as soon as we find one that's + * noncoherent. This means we only ever [un]register_noncoherent_dma once + * for the whole device. + */ +static void kvm_vfio_update_coherency(struct kvm_device *dev) +{ + struct kvm_vfio *kv = dev->private; + bool noncoherent = false; + struct kvm_vfio_file *kvf; + + list_for_each_entry(kvf, &kv->file_list, node) { + if (!kvm_vfio_file_enforced_coherent(kvf->file)) { + noncoherent = true; + break; + } + } + + if (noncoherent != kv->noncoherent) { + kv->noncoherent = noncoherent; + + if (kv->noncoherent) + kvm_arch_register_noncoherent_dma(dev->kvm); + else + kvm_arch_unregister_noncoherent_dma(dev->kvm); + } +} + +static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd) +{ + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_file *kvf; + struct file *filp __free(fput) = NULL; + + filp = fget(fd); + if (!filp) + return -EBADF; + + /* Ensure the FD is a vfio FD. */ + if (!kvm_vfio_file_is_valid(filp)) + return -EINVAL; + + guard(mutex)(&kv->lock); + + list_for_each_entry(kvf, &kv->file_list, node) { + if (kvf->file == filp) + return -EEXIST; + } + + kvf = kzalloc_obj(*kvf, GFP_KERNEL_ACCOUNT); + if (!kvf) + return -ENOMEM; + + kvf->file = get_file(filp); + list_add_tail(&kvf->node, &kv->file_list); + + kvm_vfio_file_set_kvm(kvf->file, dev->kvm); + kvm_vfio_update_coherency(dev); + + return 0; +} + +static void kvm_vfio_file_free(struct kvm_device *dev, struct kvm_vfio_file *kvf) +{ +#ifdef CONFIG_SPAPR_TCE_IOMMU + kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); +#endif + kvm_vfio_file_set_kvm(kvf->file, NULL); + fput(kvf->file); + list_del(&kvf->node); + kfree(kvf); +} + +static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd) +{ + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_file *kvf; + CLASS(fd, f)(fd); + + if (fd_empty(f)) + return -EBADF; + + guard(mutex)(&kv->lock); + + list_for_each_entry(kvf, &kv->file_list, node) { + if (kvf->file == fd_file(f)) { + kvm_vfio_file_free(dev, kvf); + kvm_vfio_update_coherency(dev); + return 0; + } + } + + return -ENOENT; +} + +#ifdef CONFIG_SPAPR_TCE_IOMMU +static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev, + void __user *arg) +{ + struct kvm_vfio_spapr_tce param; + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_file *kvf; + + if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce))) + return -EFAULT; + + CLASS(fd, f)(param.groupfd); + if (fd_empty(f)) + return -EBADF; + + guard(mutex)(&kv->lock); + + list_for_each_entry(kvf, &kv->file_list, node) { + if (kvf->file != fd_file(f)) + continue; + + if (!kvf->iommu_group) { + kvf->iommu_group = kvm_vfio_file_iommu_group(kvf->file); + if (WARN_ON_ONCE(!kvf->iommu_group)) + return -EIO; + } + + return kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd, + kvf->iommu_group); + } + + return -ENOENT; +} +#endif + +static int kvm_vfio_set_file(struct kvm_device *dev, long attr, + void __user *arg) +{ + int32_t __user *argp = arg; + int32_t fd; + + switch (attr) { + case KVM_DEV_VFIO_FILE_ADD: + if (get_user(fd, argp)) + return -EFAULT; + return kvm_vfio_file_add(dev, fd); + + case KVM_DEV_VFIO_FILE_DEL: + if (get_user(fd, argp)) + return -EFAULT; + return kvm_vfio_file_del(dev, fd); + +#ifdef CONFIG_SPAPR_TCE_IOMMU + case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: + return kvm_vfio_file_set_spapr_tce(dev, arg); +#endif + } + + return -ENXIO; +} + +static int kvm_vfio_set_attr(struct kvm_device *dev, + struct kvm_device_attr *attr) +{ + switch (attr->group) { + case KVM_DEV_VFIO_FILE: + return kvm_vfio_set_file(dev, attr->attr, + u64_to_user_ptr(attr->addr)); + } + + return -ENXIO; +} + +static int kvm_vfio_has_attr(struct kvm_device *dev, + struct kvm_device_attr *attr) +{ + switch (attr->group) { + case KVM_DEV_VFIO_FILE: + switch (attr->attr) { + case KVM_DEV_VFIO_FILE_ADD: + case KVM_DEV_VFIO_FILE_DEL: +#ifdef CONFIG_SPAPR_TCE_IOMMU + case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: +#endif + return 0; + } + + break; + } + + return -ENXIO; +} + +static void kvm_vfio_release(struct kvm_device *dev) +{ + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_file *kvf, *tmp; + + list_for_each_entry_safe(kvf, tmp, &kv->file_list, node) + kvm_vfio_file_free(dev, kvf); + + kvm_vfio_update_coherency(dev); + + kfree(kv); + kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */ +} + +static int kvm_vfio_create(struct kvm_device *dev, u32 type); + +static const struct kvm_device_ops kvm_vfio_ops = { + .name = "kvm-vfio", + .create = kvm_vfio_create, + .release = kvm_vfio_release, + .set_attr = kvm_vfio_set_attr, + .has_attr = kvm_vfio_has_attr, +}; + +static int kvm_vfio_create(struct kvm_device *dev, u32 type) +{ + struct kvm_device *tmp; + struct kvm_vfio *kv; + + lockdep_assert_held(&dev->kvm->lock); + + /* Only one VFIO "device" per VM */ + list_for_each_entry(tmp, &dev->kvm->devices, vm_node) + if (tmp->ops == &kvm_vfio_ops) + return -EBUSY; + + kv = kzalloc_obj(*kv, GFP_KERNEL_ACCOUNT); + if (!kv) + return -ENOMEM; + + INIT_LIST_HEAD(&kv->file_list); + mutex_init(&kv->lock); + + dev->private = kv; + + return 0; +} + +int kvm_vfio_ops_init(void) +{ + return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); +} + +void kvm_vfio_ops_exit(void) +{ + kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); +} diff --git a/virt/kvm/vfio.h b/virt/kvm/vfio.h new file mode 100644 index 000000000..e130a4a03 --- /dev/null +++ b/virt/kvm/vfio.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __KVM_VFIO_H +#define __KVM_VFIO_H + +#ifdef CONFIG_KVM_VFIO +int kvm_vfio_ops_init(void); +void kvm_vfio_ops_exit(void); +#else +static inline int kvm_vfio_ops_init(void) +{ + return 0; +} +static inline void kvm_vfio_ops_exit(void) +{ +} +#endif + +#endif diff --git a/virt/lib/Kconfig b/virt/lib/Kconfig new file mode 100644 index 000000000..2d9523b71 --- /dev/null +++ b/virt/lib/Kconfig @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +config IRQ_BYPASS_MANAGER + tristate diff --git a/virt/lib/Makefile b/virt/lib/Makefile new file mode 100644 index 000000000..bd7f9a78b --- /dev/null +++ b/virt/lib/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_IRQ_BYPASS_MANAGER) += irqbypass.o diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c new file mode 100644 index 000000000..62c160200 --- /dev/null +++ b/virt/lib/irqbypass.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * IRQ offload/bypass manager + * + * Copyright (C) 2015 Red Hat, Inc. + * Copyright (c) 2015 Linaro Ltd. + * + * Various virtualization hardware acceleration techniques allow bypassing or + * offloading interrupts received from devices around the host kernel. Posted + * Interrupts on Intel VT-d systems can allow interrupts to be received + * directly by a virtual machine. ARM IRQ Forwarding allows forwarded physical + * interrupts to be directly deactivated by the guest. This manager allows + * interrupt producers and consumers to find each other to enable this sort of + * bypass. + */ + +#include <linux/irqbypass.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("IRQ bypass manager utility module"); + +static DEFINE_XARRAY(producers); +static DEFINE_XARRAY(consumers); +static DEFINE_MUTEX(lock); + +/* @lock must be held when calling connect */ +static int __connect(struct irq_bypass_producer *prod, + struct irq_bypass_consumer *cons) +{ + int ret = 0; + + if (prod->stop) + prod->stop(prod); + if (cons->stop) + cons->stop(cons); + + if (prod->add_consumer) + ret = prod->add_consumer(prod, cons); + + if (!ret) { + ret = cons->add_producer(cons, prod); + if (ret && prod->del_consumer) + prod->del_consumer(prod, cons); + } + + if (cons->start) + cons->start(cons); + if (prod->start) + prod->start(prod); + + if (!ret) { + prod->consumer = cons; + cons->producer = prod; + } + return ret; +} + +/* @lock must be held when calling disconnect */ +static void __disconnect(struct irq_bypass_producer *prod, + struct irq_bypass_consumer *cons) +{ + if (prod->stop) + prod->stop(prod); + if (cons->stop) + cons->stop(cons); + + cons->del_producer(cons, prod); + + if (prod->del_consumer) + prod->del_consumer(prod, cons); + + if (cons->start) + cons->start(cons); + if (prod->start) + prod->start(prod); + + prod->consumer = NULL; + cons->producer = NULL; +} + +/** + * irq_bypass_register_producer - register IRQ bypass producer + * @producer: pointer to producer structure + * @eventfd: pointer to the eventfd context associated with the producer + * @irq: Linux IRQ number of the underlying producer device + * + * Add the provided IRQ producer to the set of producers and connect with the + * consumer with a matching eventfd, if one exists. + */ +int irq_bypass_register_producer(struct irq_bypass_producer *producer, + struct eventfd_ctx *eventfd, int irq) +{ + unsigned long index = (unsigned long)eventfd; + struct irq_bypass_consumer *consumer; + int ret; + + if (WARN_ON_ONCE(producer->eventfd)) + return -EINVAL; + + producer->irq = irq; + + guard(mutex)(&lock); + + ret = xa_insert(&producers, index, producer, GFP_KERNEL); + if (ret) + return ret; + + consumer = xa_load(&consumers, index); + if (consumer) { + ret = __connect(producer, consumer); + if (ret) { + WARN_ON_ONCE(xa_erase(&producers, index) != producer); + return ret; + } + } + + producer->eventfd = eventfd; + return 0; +} +EXPORT_SYMBOL_GPL(irq_bypass_register_producer); + +/** + * irq_bypass_unregister_producer - unregister IRQ bypass producer + * @producer: pointer to producer structure + * + * Remove a previously registered IRQ producer (note, it's safe to call this + * even if registration was unsuccessful). Disconnect from the associated + * consumer, if one exists. + */ +void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) +{ + unsigned long index = (unsigned long)producer->eventfd; + + if (!producer->eventfd) + return; + + guard(mutex)(&lock); + + if (producer->consumer) + __disconnect(producer, producer->consumer); + + WARN_ON_ONCE(xa_erase(&producers, index) != producer); + producer->eventfd = NULL; +} +EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer); + +/** + * irq_bypass_register_consumer - register IRQ bypass consumer + * @consumer: pointer to consumer structure + * @eventfd: pointer to the eventfd context associated with the consumer + * + * Add the provided IRQ consumer to the set of consumers and connect with the + * producer with a matching eventfd, if one exists. + */ +int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer, + struct eventfd_ctx *eventfd) +{ + unsigned long index = (unsigned long)eventfd; + struct irq_bypass_producer *producer; + int ret; + + if (WARN_ON_ONCE(consumer->eventfd)) + return -EINVAL; + + if (!consumer->add_producer || !consumer->del_producer) + return -EINVAL; + + guard(mutex)(&lock); + + ret = xa_insert(&consumers, index, consumer, GFP_KERNEL); + if (ret) + return ret; + + producer = xa_load(&producers, index); + if (producer) { + ret = __connect(producer, consumer); + if (ret) { + WARN_ON_ONCE(xa_erase(&consumers, index) != consumer); + return ret; + } + } + + consumer->eventfd = eventfd; + return 0; +} +EXPORT_SYMBOL_GPL(irq_bypass_register_consumer); + +/** + * irq_bypass_unregister_consumer - unregister IRQ bypass consumer + * @consumer: pointer to consumer structure + * + * Remove a previously registered IRQ consumer (note, it's safe to call this + * even if registration was unsuccessful). Disconnect from the associated + * producer, if one exists. + */ +void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) +{ + unsigned long index = (unsigned long)consumer->eventfd; + + if (!consumer->eventfd) + return; + + guard(mutex)(&lock); + + if (consumer->producer) + __disconnect(consumer->producer, consumer); + + WARN_ON_ONCE(xa_erase(&consumers, index) != consumer); + consumer->eventfd = NULL; +} +EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer); |