diff options
Diffstat (limited to 'drivers/hv/hv.c')
| -rw-r--r-- | drivers/hv/hv.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c new file mode 100644 index 000000000..ef4b1b033 --- /dev/null +++ b/drivers/hv/hv.c @@ -0,0 +1,658 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2009, Microsoft Corporation. + * + * Authors: + * Haiyang Zhang <haiyangz@microsoft.com> + * Hank Janssen <hjanssen@microsoft.com> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/hyperv.h> +#include <linux/random.h> +#include <linux/clockchips.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/export.h> +#include <clocksource/hyperv_timer.h> +#include <asm/mshyperv.h> +#include <linux/set_memory.h> +#include "hyperv_vmbus.h" + +/* The one and only */ +struct hv_context hv_context; +EXPORT_SYMBOL_FOR_MODULES(hv_context, "mshv_vtl"); + +/* + * hv_init - Main initialization routine. + * + * This routine must be called before any other routines in here are called + */ +int hv_init(void) +{ + hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context); + if (!hv_context.cpu_context) + return -ENOMEM; + return 0; +} + +/* + * hv_post_message - Post a message using the hypervisor message IPC. + * + * This involves a hypercall. + */ +int hv_post_message(union hv_connection_id connection_id, + enum hv_message_type message_type, + void *payload, size_t payload_size) +{ + struct hv_input_post_message *aligned_msg; + unsigned long flags; + u64 status; + + if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) + return -EMSGSIZE; + + local_irq_save(flags); + + /* + * A TDX VM with the paravisor must use the decrypted post_msg_page: see + * the comment in struct hv_per_cpu_context. A SNP VM with the paravisor + * can use the encrypted hyperv_pcpu_input_arg because it copies the + * input into the GHCB page, which has been decrypted by the paravisor. + */ + if (hv_isolation_type_tdx() && ms_hyperv.paravisor_present) + aligned_msg = this_cpu_ptr(hv_context.cpu_context)->post_msg_page; + else + aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg); + + aligned_msg->connectionid = connection_id; + aligned_msg->reserved = 0; + aligned_msg->message_type = message_type; + aligned_msg->payload_size = payload_size; + memcpy((void *)aligned_msg->payload, payload, payload_size); + + if (ms_hyperv.paravisor_present && !vmbus_is_confidential()) { + /* + * If the VMBus isn't confidential, use the CoCo-specific + * mechanism to communicate with the hypervisor. + */ + if (hv_isolation_type_tdx()) + status = hv_tdx_hypercall(HVCALL_POST_MESSAGE, + virt_to_phys(aligned_msg), 0); + else if (hv_isolation_type_snp()) + status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE, + aligned_msg, NULL, + sizeof(*aligned_msg)); + else + status = HV_STATUS_INVALID_PARAMETER; + } else { + u64 control = HVCALL_POST_MESSAGE; + + control |= hv_nested ? HV_HYPERCALL_NESTED : 0; + /* + * If there is no paravisor, this will go to the hypervisor. + * In the Confidential VMBus case, there is the paravisor + * to which this will trap. + */ + status = hv_do_hypercall(control, aligned_msg, NULL); + } + + local_irq_restore(flags); + + return hv_result(status); +} +EXPORT_SYMBOL_FOR_MODULES(hv_post_message, "mshv_vtl"); + +static int hv_alloc_page(void **page, bool decrypt, const char *note) +{ + int ret = 0; + + /* + * After the page changes its encryption status, its contents might + * appear scrambled on some hardware. Thus `get_zeroed_page` would + * zero the page out in vain, so do that explicitly exactly once. + * + * By default, the page is allocated encrypted in a CoCo VM. + */ + *page = (void *)__get_free_page(GFP_KERNEL); + if (!*page) + return -ENOMEM; + + if (decrypt) + ret = set_memory_decrypted((unsigned long)*page, 1); + if (ret) + goto failed; + + memset(*page, 0, PAGE_SIZE); + return 0; + +failed: + /* + * Report the failure but don't put the page back on the free list as + * its encryption status is unknown. + */ + pr_err("allocation failed for %s page, error %d, decrypted %d\n", + note, ret, decrypt); + *page = NULL; + return ret; +} + +static int hv_free_page(void **page, bool encrypt, const char *note) +{ + int ret = 0; + + if (!*page) + return 0; + + if (encrypt) + ret = set_memory_encrypted((unsigned long)*page, 1); + + /* + * In the case of the failure, the page is leaked. Something is wrong, + * prefer to lose the page with the unknown encryption status and stay afloat. + */ + if (ret) + pr_err("deallocation failed for %s page, error %d, encrypt %d\n", + note, ret, encrypt); + else + free_page((unsigned long)*page); + + *page = NULL; + + return ret; +} + +int hv_synic_alloc(void) +{ + int cpu, ret = -ENOMEM; + struct hv_per_cpu_context *hv_cpu; + const bool decrypt = !vmbus_is_confidential(); + + /* + * First, zero all per-cpu memory areas so hv_synic_free() can + * detect what memory has been allocated and cleanup properly + * after any failures. + */ + for_each_present_cpu(cpu) { + hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); + memset(hv_cpu, 0, sizeof(*hv_cpu)); + } + + hv_context.hv_numa_map = kzalloc_objs(struct cpumask, nr_node_ids); + if (!hv_context.hv_numa_map) { + pr_err("Unable to allocate NUMA map\n"); + goto err; + } + + for_each_present_cpu(cpu) { + hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); + + tasklet_init(&hv_cpu->msg_dpc, + vmbus_on_msg_dpc, (unsigned long)hv_cpu); + + if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) { + ret = hv_alloc_page(&hv_cpu->post_msg_page, + decrypt, "post msg"); + if (ret) + goto err; + } + + /* + * If these SynIC pages are not allocated, SIEF and SIM pages + * are configured using what the root partition or the paravisor + * provides upon reading the SIEFP and SIMP registers. + */ + if (!ms_hyperv.paravisor_present && !hv_root_partition()) { + ret = hv_alloc_page(&hv_cpu->hyp_synic_message_page, + decrypt, "hypervisor SynIC msg"); + if (ret) + goto err; + ret = hv_alloc_page(&hv_cpu->hyp_synic_event_page, + decrypt, "hypervisor SynIC event"); + if (ret) + goto err; + } + + if (vmbus_is_confidential()) { + ret = hv_alloc_page(&hv_cpu->para_synic_message_page, + false, "paravisor SynIC msg"); + if (ret) + goto err; + ret = hv_alloc_page(&hv_cpu->para_synic_event_page, + false, "paravisor SynIC event"); + if (ret) + goto err; + } + } + + return 0; + +err: + /* + * Any memory allocations that succeeded will be freed when + * the caller cleans up by calling hv_synic_free() + */ + return ret; +} + +void hv_synic_free(void) +{ + int cpu; + const bool encrypt = !vmbus_is_confidential(); + + for_each_present_cpu(cpu) { + struct hv_per_cpu_context *hv_cpu = + per_cpu_ptr(hv_context.cpu_context, cpu); + + if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) + hv_free_page(&hv_cpu->post_msg_page, + encrypt, "post msg"); + if (!ms_hyperv.paravisor_present && !hv_root_partition()) { + hv_free_page(&hv_cpu->hyp_synic_event_page, + encrypt, "hypervisor SynIC event"); + hv_free_page(&hv_cpu->hyp_synic_message_page, + encrypt, "hypervisor SynIC msg"); + } + if (vmbus_is_confidential()) { + hv_free_page(&hv_cpu->para_synic_event_page, + false, "paravisor SynIC event"); + hv_free_page(&hv_cpu->para_synic_message_page, + false, "paravisor SynIC msg"); + } + } + + kfree(hv_context.hv_numa_map); +} + +/* + * hv_hyp_synic_enable_regs - Initialize the Synthetic Interrupt Controller + * with the hypervisor. + * + * Note: When MSHV is present, mshv_synic_cpu_init() intializes further + * registers later. + */ +void hv_hyp_synic_enable_regs(unsigned int cpu) +{ + struct hv_per_cpu_context *hv_cpu = + per_cpu_ptr(hv_context.cpu_context, cpu); + union hv_synic_simp simp; + union hv_synic_siefp siefp; + union hv_synic_sint shared_sint; + + /* Setup the Synic's message page with the hypervisor. */ + simp.as_uint64 = hv_get_msr(HV_MSR_SIMP); + simp.simp_enabled = 1; + + if (ms_hyperv.paravisor_present || hv_root_partition()) { + /* Mask out vTOM bit and map as decrypted */ + u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) & + ~ms_hyperv.shared_gpa_boundary; + hv_cpu->hyp_synic_message_page = + memremap(base, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC); + if (!hv_cpu->hyp_synic_message_page) + pr_err("Fail to map synic message page.\n"); + } else { + simp.base_simp_gpa = virt_to_phys(hv_cpu->hyp_synic_message_page) + >> HV_HYP_PAGE_SHIFT; + } + + hv_set_msr(HV_MSR_SIMP, simp.as_uint64); + + /* Setup the Synic's event page with the hypervisor. */ + siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP); + siefp.siefp_enabled = 1; + + if (ms_hyperv.paravisor_present || hv_root_partition()) { + /* Mask out vTOM bit and map as decrypted */ + u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) & + ~ms_hyperv.shared_gpa_boundary; + hv_cpu->hyp_synic_event_page = + memremap(base, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC); + if (!hv_cpu->hyp_synic_event_page) + pr_err("Fail to map synic event page.\n"); + } else { + siefp.base_siefp_gpa = virt_to_phys(hv_cpu->hyp_synic_event_page) + >> HV_HYP_PAGE_SHIFT; + } + + hv_set_msr(HV_MSR_SIEFP, siefp.as_uint64); + hv_enable_coco_interrupt(cpu, vmbus_interrupt, true); + + /* Setup the shared SINT. */ + if (vmbus_irq != -1) + enable_percpu_irq(vmbus_irq, 0); + shared_sint.as_uint64 = hv_get_msr(HV_MSR_SINT0 + VMBUS_MESSAGE_SINT); + + shared_sint.vector = vmbus_interrupt; + shared_sint.masked = false; + shared_sint.auto_eoi = hv_recommend_using_aeoi(); + hv_set_msr(HV_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64); +} + +static void hv_hyp_synic_enable_interrupts(void) +{ + union hv_synic_scontrol sctrl; + + /* Enable the global synic bit */ + sctrl.as_uint64 = hv_get_msr(HV_MSR_SCONTROL); + sctrl.enable = 1; + + hv_set_msr(HV_MSR_SCONTROL, sctrl.as_uint64); +} + +static void hv_para_synic_enable_regs(unsigned int cpu) +{ + union hv_synic_simp simp; + union hv_synic_siefp siefp; + struct hv_per_cpu_context *hv_cpu + = per_cpu_ptr(hv_context.cpu_context, cpu); + + /* Setup the Synic's message page with the paravisor. */ + simp.as_uint64 = hv_para_get_synic_register(HV_MSR_SIMP); + simp.simp_enabled = 1; + simp.base_simp_gpa = virt_to_phys(hv_cpu->para_synic_message_page) + >> HV_HYP_PAGE_SHIFT; + hv_para_set_synic_register(HV_MSR_SIMP, simp.as_uint64); + + /* Setup the Synic's event page with the paravisor. */ + siefp.as_uint64 = hv_para_get_synic_register(HV_MSR_SIEFP); + siefp.siefp_enabled = 1; + siefp.base_siefp_gpa = virt_to_phys(hv_cpu->para_synic_event_page) + >> HV_HYP_PAGE_SHIFT; + hv_para_set_synic_register(HV_MSR_SIEFP, siefp.as_uint64); +} + +static void hv_para_synic_enable_interrupts(void) +{ + union hv_synic_scontrol sctrl; + + /* Enable the global synic bit */ + sctrl.as_uint64 = hv_para_get_synic_register(HV_MSR_SCONTROL); + sctrl.enable = 1; + hv_para_set_synic_register(HV_MSR_SCONTROL, sctrl.as_uint64); +} + +int hv_synic_init(unsigned int cpu) +{ + if (vmbus_is_confidential()) + hv_para_synic_enable_regs(cpu); + + /* + * The SINT is set in hv_hyp_synic_enable_regs() by calling + * hv_set_msr(). hv_set_msr() in turn has special case code for the + * SINT MSRs that write to the hypervisor version of the MSR *and* + * the paravisor version of the MSR (but *without* the proxy bit when + * VMBus is confidential). + * + * Then enable interrupts via the paravisor if VMBus is confidential, + * and otherwise via the hypervisor. + */ + + hv_hyp_synic_enable_regs(cpu); + if (vmbus_is_confidential()) + hv_para_synic_enable_interrupts(); + else + hv_hyp_synic_enable_interrupts(); + + hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT); + + return 0; +} + +void hv_hyp_synic_disable_regs(unsigned int cpu) +{ + struct hv_per_cpu_context *hv_cpu = + per_cpu_ptr(hv_context.cpu_context, cpu); + union hv_synic_sint shared_sint; + union hv_synic_simp simp; + union hv_synic_siefp siefp; + + shared_sint.as_uint64 = hv_get_msr(HV_MSR_SINT0 + VMBUS_MESSAGE_SINT); + + shared_sint.masked = 1; + + /* Need to correctly cleanup in the case of SMP!!! */ + /* Disable the interrupt */ + hv_set_msr(HV_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64); + hv_enable_coco_interrupt(cpu, vmbus_interrupt, false); + + simp.as_uint64 = hv_get_msr(HV_MSR_SIMP); + /* + * In Isolation VM, simp and sief pages are allocated by + * paravisor. These pages also will be used by kdump + * kernel. So just reset enable bit here and keep page + * addresses. + */ + simp.simp_enabled = 0; + if (ms_hyperv.paravisor_present || hv_root_partition()) { + if (hv_cpu->hyp_synic_message_page) { + memunmap(hv_cpu->hyp_synic_message_page); + hv_cpu->hyp_synic_message_page = NULL; + } + } else { + simp.base_simp_gpa = 0; + } + + hv_set_msr(HV_MSR_SIMP, simp.as_uint64); + + siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP); + siefp.siefp_enabled = 0; + + if (ms_hyperv.paravisor_present || hv_root_partition()) { + if (hv_cpu->hyp_synic_event_page) { + memunmap(hv_cpu->hyp_synic_event_page); + hv_cpu->hyp_synic_event_page = NULL; + } + } else { + siefp.base_siefp_gpa = 0; + } + + hv_set_msr(HV_MSR_SIEFP, siefp.as_uint64); +} + +static void hv_hyp_synic_disable_interrupts(void) +{ + union hv_synic_scontrol sctrl; + + /* Disable the global synic bit */ + sctrl.as_uint64 = hv_get_msr(HV_MSR_SCONTROL); + sctrl.enable = 0; + hv_set_msr(HV_MSR_SCONTROL, sctrl.as_uint64); +} + +static void hv_para_synic_disable_regs(unsigned int cpu) +{ + union hv_synic_simp simp; + union hv_synic_siefp siefp; + + /* Disable SynIC's message page in the paravisor. */ + simp.as_uint64 = hv_para_get_synic_register(HV_MSR_SIMP); + simp.simp_enabled = 0; + hv_para_set_synic_register(HV_MSR_SIMP, simp.as_uint64); + + /* Disable SynIC's event page in the paravisor. */ + siefp.as_uint64 = hv_para_get_synic_register(HV_MSR_SIEFP); + siefp.siefp_enabled = 0; + hv_para_set_synic_register(HV_MSR_SIEFP, siefp.as_uint64); +} + +static void hv_para_synic_disable_interrupts(void) +{ + union hv_synic_scontrol sctrl; + + /* Disable the global synic bit */ + sctrl.as_uint64 = hv_para_get_synic_register(HV_MSR_SCONTROL); + sctrl.enable = 0; + hv_para_set_synic_register(HV_MSR_SCONTROL, sctrl.as_uint64); +} + +#define HV_MAX_TRIES 3 +/* + * Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one + * bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times. + * Return 'true', if there is still any set bit after this operation; 'false', otherwise. + * + * If a bit is set, that means there is a pending channel interrupt. The expectation is + * that the normal interrupt handling mechanism will find and process the channel interrupt + * "very soon", and in the process clear the bit. + */ +static bool __hv_synic_event_pending(union hv_synic_event_flags *event, int sint) +{ + unsigned long *recv_int_page; + bool pending; + u32 relid; + int tries = 0; + + if (!event) + return false; + + event += sint; + recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */ +retry: + pending = false; + for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) { + /* Special case - VMBus channel protocol messages */ + if (relid == 0) + continue; + pending = true; + break; + } + if (pending && tries++ < HV_MAX_TRIES) { + usleep_range(10000, 20000); + goto retry; + } + return pending; +} + +static bool hv_synic_event_pending(void) +{ + struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context); + union hv_synic_event_flags *hyp_synic_event_page = hv_cpu->hyp_synic_event_page; + union hv_synic_event_flags *para_synic_event_page = hv_cpu->para_synic_event_page; + + return + __hv_synic_event_pending(hyp_synic_event_page, VMBUS_MESSAGE_SINT) || + __hv_synic_event_pending(para_synic_event_page, VMBUS_MESSAGE_SINT); +} + +static int hv_pick_new_cpu(struct vmbus_channel *channel) +{ + int ret = -EBUSY; + int start; + int cpu; + + lockdep_assert_cpus_held(); + lockdep_assert_held(&vmbus_connection.channel_mutex); + + /* + * We can't assume that the relevant interrupts will be sent before + * the cpu is offlined on older versions of hyperv. + */ + if (vmbus_proto_version < VERSION_WIN10_V5_3) + return -EBUSY; + + start = get_random_u32_below(nr_cpu_ids); + + for_each_cpu_wrap(cpu, cpu_online_mask, start) { + if (channel->target_cpu == cpu || + channel->target_cpu == VMBUS_CONNECT_CPU) + continue; + + ret = vmbus_channel_set_cpu(channel, cpu); + if (!ret) + break; + } + + if (ret) + ret = vmbus_channel_set_cpu(channel, VMBUS_CONNECT_CPU); + + return ret; +} + +/* + * hv_synic_cleanup - Cleanup routine for hv_synic_init(). + */ +int hv_synic_cleanup(unsigned int cpu) +{ + struct vmbus_channel *channel, *sc; + int ret = 0; + + if (vmbus_connection.conn_state != CONNECTED) + goto always_cleanup; + + /* + * Hyper-V does not provide a way to change the connect CPU once + * it is set; we must prevent the connect CPU from going offline + * while the VM is running normally. But in the panic or kexec() + * path where the vmbus is already disconnected, the CPU must be + * allowed to shut down. + */ + if (cpu == VMBUS_CONNECT_CPU) + return -EBUSY; + + /* + * Search for channels which are bound to the CPU we're about to + * cleanup. + */ + mutex_lock(&vmbus_connection.channel_mutex); + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { + if (channel->target_cpu == cpu) { + ret = hv_pick_new_cpu(channel); + if (ret) { + mutex_unlock(&vmbus_connection.channel_mutex); + return ret; + } + } + list_for_each_entry(sc, &channel->sc_list, sc_list) { + if (sc->target_cpu == cpu) { + ret = hv_pick_new_cpu(sc); + if (ret) { + mutex_unlock(&vmbus_connection.channel_mutex); + return ret; + } + } + } + } + mutex_unlock(&vmbus_connection.channel_mutex); + + /* + * Scan the event flags page looking for bits that are set and waiting + * with a timeout for vmbus_chan_sched() to process such bits. If bits + * are still set after this operation and VMBus is connected, fail the + * CPU offlining operation. + */ + if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending()) + return -EBUSY; + +always_cleanup: + hv_stimer_legacy_cleanup(cpu); + + /* + * First, disable the event and message pages + * used for communicating with the host, and then + * disable the host interrupts if VMBus is not + * confidential. + */ + hv_hyp_synic_disable_regs(cpu); + if (!vmbus_is_confidential()) + hv_hyp_synic_disable_interrupts(); + + /* + * Perform the same steps for the Confidential VMBus. + * The sequencing provides the guarantee that no data + * may be posted for processing before disabling interrupts. + */ + if (vmbus_is_confidential()) { + hv_para_synic_disable_regs(cpu); + hv_para_synic_disable_interrupts(); + } + if (vmbus_irq != -1) + disable_percpu_irq(vmbus_irq); + + return ret; +} |