diff options
Diffstat (limited to 'drivers/hv/channel.c')
| -rw-r--r-- | drivers/hv/channel.c | 1475 |
1 files changed, 1475 insertions, 0 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c new file mode 100644 index 000000000..7e4cc6f55 --- /dev/null +++ b/drivers/hv/channel.c @@ -0,0 +1,1475 @@ +// 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/kernel.h> +#include <linux/sched.h> +#include <linux/wait.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/log2.h> +#include <linux/module.h> +#include <linux/hyperv.h> +#include <linux/uio.h> +#include <linux/interrupt.h> +#include <linux/set_memory.h> +#include <linux/vmalloc.h> +#include <linux/export.h> +#include <asm/page.h> +#include <asm/mshyperv.h> + +#include "hyperv_vmbus.h" + +/* + * hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses + * + * For BUFFER gpadl, Hyper-V uses the exact same size as the guest does. + * + * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header + * (because of the alignment requirement), however, the hypervisor only + * uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a + * (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a + * ringbuffer, the total size for a RING gpadl that Hyper-V uses is the + * total size that the guest uses minus twice of the gap size. + */ +static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size) +{ + switch (type) { + case HV_GPADL_BUFFER: + case HV_GPADL_BUFFER_DECRYPTED: + return size; + case HV_GPADL_RING: + /* The size of a ringbuffer must be page-aligned */ + BUG_ON(size % PAGE_SIZE); + /* + * Two things to notice here: + * 1) We're processing two ring buffers as a unit + * 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in + * the first guest-size page of each of the two ring buffers. + * So we effectively subtract out two guest-size pages, and add + * back two Hyper-V size pages. + */ + return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE); + } + BUG(); + return 0; +} + +/* + * hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of + * HV_HYP_PAGE) in a ring gpadl based on the + * offset in the guest + * + * @offset: the offset (in bytes) where the send ringbuffer starts in the + * virtual address space of the guest + */ +static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset) +{ + + /* + * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the + * header (because of the alignment requirement), however, the + * hypervisor only uses the first HV_HYP_PAGE_SIZE as the header, + * therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. + * + * And to calculate the effective send offset in gpadl, we need to + * substract this gap. + */ + return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT; +} + +/* + * hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in + * the gpadl + * + * @type: the type of the gpadl + * @kbuffer: the pointer to the gpadl in the guest + * @size: the total size (in bytes) of the gpadl + * @send_offset: the offset (in bytes) where the send ringbuffer starts in the + * virtual address space of the guest + * @i: the index + */ +static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer, + u32 size, u32 send_offset, int i) +{ + int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset); + unsigned long delta = 0UL; + + switch (type) { + case HV_GPADL_BUFFER: + case HV_GPADL_BUFFER_DECRYPTED: + break; + case HV_GPADL_RING: + if (i == 0) + delta = 0; + else if (i <= send_idx) + delta = PAGE_SIZE - HV_HYP_PAGE_SIZE; + else + delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE); + break; + default: + BUG(); + break; + } + + return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i)); +} + +/* + * vmbus_setevent- Trigger an event notification on the specified + * channel. + */ +void vmbus_setevent(struct vmbus_channel *channel) +{ + struct hv_monitor_page *monitorpage; + + trace_vmbus_setevent(channel); + + /* + * For channels marked as in "low latency" mode + * bypass the monitor page mechanism. + */ + if (channel->offermsg.monitor_allocated && !channel->low_latency) { + vmbus_send_interrupt(channel->offermsg.child_relid); + + /* Get the child to parent monitor page */ + monitorpage = vmbus_connection.monitor_pages[1]; + + sync_set_bit(channel->monitor_bit, + (unsigned long *)&monitorpage->trigger_group + [channel->monitor_grp].pending); + + } else { + vmbus_set_event(channel); + } +} +EXPORT_SYMBOL_GPL(vmbus_setevent); + +/* vmbus_free_ring - drop mapping of ring buffer */ +void vmbus_free_ring(struct vmbus_channel *channel) +{ + hv_ringbuffer_cleanup(&channel->outbound); + hv_ringbuffer_cleanup(&channel->inbound); + + if (channel->ringbuffer_page) { + /* In a CoCo VM leak the memory if it didn't get re-encrypted */ + if (!channel->ringbuffer_gpadlhandle.decrypted) + __free_pages(channel->ringbuffer_page, + get_order(channel->ringbuffer_pagecount + << PAGE_SHIFT)); + channel->ringbuffer_page = NULL; + } +} +EXPORT_SYMBOL_GPL(vmbus_free_ring); + +/* vmbus_alloc_ring - allocate and map pages for ring buffer */ +int vmbus_alloc_ring(struct vmbus_channel *newchannel, + u32 send_size, u32 recv_size) +{ + struct page *page; + int order; + + if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE) + return -EINVAL; + + /* Allocate the ring buffer */ + order = get_order(send_size + recv_size); + page = alloc_pages_node(cpu_to_node(newchannel->target_cpu), + GFP_KERNEL|__GFP_ZERO, order); + + if (!page) + page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order); + + if (!page) + return -ENOMEM; + + newchannel->ringbuffer_page = page; + newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT; + newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT; + + return 0; +} +EXPORT_SYMBOL_GPL(vmbus_alloc_ring); + +/* Used for Hyper-V Socket: a guest client's connect() to the host */ +int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id, + const guid_t *shv_host_servie_id) +{ + struct vmbus_channel_tl_connect_request conn_msg; + int ret; + + memset(&conn_msg, 0, sizeof(conn_msg)); + conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST; + conn_msg.guest_endpoint_id = *shv_guest_servie_id; + conn_msg.host_service_id = *shv_host_servie_id; + + ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true); + + trace_vmbus_send_tl_connect_request(&conn_msg, ret); + + return ret; +} +EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request); + +static int send_modifychannel_without_ack(struct vmbus_channel *channel, u32 target_vp) +{ + struct vmbus_channel_modifychannel msg; + int ret; + + memset(&msg, 0, sizeof(msg)); + msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL; + msg.child_relid = channel->offermsg.child_relid; + msg.target_vp = target_vp; + + ret = vmbus_post_msg(&msg, sizeof(msg), true); + trace_vmbus_send_modifychannel(&msg, ret); + + return ret; +} + +static int send_modifychannel_with_ack(struct vmbus_channel *channel, u32 target_vp) +{ + struct vmbus_channel_modifychannel *msg; + struct vmbus_channel_msginfo *info; + unsigned long flags; + int ret; + + info = kzalloc(sizeof(struct vmbus_channel_msginfo) + + sizeof(struct vmbus_channel_modifychannel), + GFP_KERNEL); + if (!info) + return -ENOMEM; + + init_completion(&info->waitevent); + info->waiting_channel = channel; + + msg = (struct vmbus_channel_modifychannel *)info->msg; + msg->header.msgtype = CHANNELMSG_MODIFYCHANNEL; + msg->child_relid = channel->offermsg.child_relid; + msg->target_vp = target_vp; + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + ret = vmbus_post_msg(msg, sizeof(*msg), true); + trace_vmbus_send_modifychannel(msg, ret); + if (ret != 0) { + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&info->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + goto free_info; + } + + /* + * Release channel_mutex; otherwise, vmbus_onoffer_rescind() could block on + * the mutex and be unable to signal the completion. + * + * See the caller target_cpu_store() for information about the usage of the + * mutex. + */ + mutex_unlock(&vmbus_connection.channel_mutex); + wait_for_completion(&info->waitevent); + mutex_lock(&vmbus_connection.channel_mutex); + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&info->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (info->response.modify_response.status) + ret = -EAGAIN; + +free_info: + kfree(info); + return ret; +} + +/* + * Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt. + * + * CHANNELMSG_MODIFYCHANNEL messages are aynchronous. When VMbus version 5.3 + * or later is negotiated, Hyper-V always sends an ACK in response to such a + * message. For VMbus version 5.2 and earlier, it never sends an ACK. With- + * out an ACK, we can not know when the host will stop interrupting the "old" + * vCPU and start interrupting the "new" vCPU for the given channel. + * + * The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version + * VERSION_WIN10_V4_1. + */ +int vmbus_send_modifychannel(struct vmbus_channel *channel, u32 target_vp) +{ + if (vmbus_proto_version >= VERSION_WIN10_V5_3) + return send_modifychannel_with_ack(channel, target_vp); + return send_modifychannel_without_ack(channel, target_vp); +} +EXPORT_SYMBOL_GPL(vmbus_send_modifychannel); + +/* + * create_gpadl_header - Creates a gpadl for the specified buffer + */ +static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer, + u32 size, u32 send_offset, + struct vmbus_channel_msginfo **msginfo) +{ + int i; + int pagecount; + struct vmbus_channel_gpadl_header *gpadl_header; + struct vmbus_channel_gpadl_body *gpadl_body; + struct vmbus_channel_msginfo *msgheader; + struct vmbus_channel_msginfo *msgbody = NULL; + u32 msgsize; + + int pfnsum, pfncount, pfnleft, pfncurr, pfnsize; + + pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT; + + pfnsize = MAX_SIZE_CHANNEL_MESSAGE - + sizeof(struct vmbus_channel_gpadl_header) - + sizeof(struct gpa_range); + pfncount = umin(pagecount, pfnsize / sizeof(u64)); + + msgsize = sizeof(struct vmbus_channel_msginfo) + + sizeof(struct vmbus_channel_gpadl_header) + + sizeof(struct gpa_range) + pfncount * sizeof(u64); + msgheader = kzalloc(msgsize, GFP_KERNEL); + if (!msgheader) + return -ENOMEM; + + INIT_LIST_HEAD(&msgheader->submsglist); + msgheader->msgsize = msgsize; + + gpadl_header = (struct vmbus_channel_gpadl_header *) + msgheader->msg; + gpadl_header->rangecount = 1; + gpadl_header->range_buflen = sizeof(struct gpa_range) + + pagecount * sizeof(u64); + gpadl_header->range[0].byte_offset = 0; + gpadl_header->range[0].byte_count = hv_gpadl_size(type, size); + for (i = 0; i < pfncount; i++) + gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn( + type, kbuffer, size, send_offset, i); + *msginfo = msgheader; + + pfnsum = pfncount; + pfnleft = pagecount - pfncount; + + /* how many pfns can we fit in a body message */ + pfnsize = MAX_SIZE_CHANNEL_MESSAGE - + sizeof(struct vmbus_channel_gpadl_body); + pfncount = pfnsize / sizeof(u64); + + /* + * If pfnleft is zero, everything fits in the header and no body + * messages are needed + */ + while (pfnleft) { + pfncurr = umin(pfncount, pfnleft); + msgsize = sizeof(struct vmbus_channel_msginfo) + + sizeof(struct vmbus_channel_gpadl_body) + + pfncurr * sizeof(u64); + msgbody = kzalloc(msgsize, GFP_KERNEL); + + if (!msgbody) { + struct vmbus_channel_msginfo *pos = NULL; + struct vmbus_channel_msginfo *tmp = NULL; + /* + * Free up all the allocated messages. + */ + list_for_each_entry_safe(pos, tmp, + &msgheader->submsglist, + msglistentry) { + + list_del(&pos->msglistentry); + kfree(pos); + } + kfree(msgheader); + return -ENOMEM; + } + + msgbody->msgsize = msgsize; + gpadl_body = (struct vmbus_channel_gpadl_body *)msgbody->msg; + + /* + * Gpadl is u32 and we are using a pointer which could + * be 64-bit + * This is governed by the guest/host protocol and + * so the hypervisor guarantees that this is ok. + */ + for (i = 0; i < pfncurr; i++) + gpadl_body->pfn[i] = hv_gpadl_hvpfn(type, + kbuffer, size, send_offset, pfnsum + i); + + /* add to msg header */ + list_add_tail(&msgbody->msglistentry, &msgheader->submsglist); + pfnsum += pfncurr; + pfnleft -= pfncurr; + } + + return 0; +} + +static void vmbus_free_channel_msginfo(struct vmbus_channel_msginfo *msginfo) +{ + struct vmbus_channel_msginfo *submsginfo, *tmp; + + if (!msginfo) + return; + + list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist, + msglistentry) { + kfree(submsginfo); + } + + kfree(msginfo); +} + +/* + * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer + * + * @channel: a channel + * @type: the type of the corresponding GPADL, only meaningful for the guest. + * @kbuffer: from kmalloc or vmalloc + * @size: page-size multiple + * @send_offset: the offset (in bytes) where the send ring buffer starts, + * should be 0 for BUFFER type gpadl + * @gpadl_handle: some funky thing + */ +static int __vmbus_establish_gpadl(struct vmbus_channel *channel, + enum hv_gpadl_type type, void *kbuffer, + u32 size, u32 send_offset, + struct vmbus_gpadl *gpadl) +{ + struct vmbus_channel_gpadl_header *gpadlmsg; + struct vmbus_channel_gpadl_body *gpadl_body; + struct vmbus_channel_msginfo *msginfo = NULL; + struct vmbus_channel_msginfo *submsginfo; + struct list_head *curr; + u32 next_gpadl_handle; + unsigned long flags; + int ret = 0; + + next_gpadl_handle = + (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1); + + ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo); + if (ret) { + gpadl->decrypted = false; + return ret; + } + + gpadl->decrypted = !((channel->co_external_memory && type == HV_GPADL_BUFFER) || + (channel->co_ring_buffer && type == HV_GPADL_RING) || + (type == HV_GPADL_BUFFER_DECRYPTED)); + if (gpadl->decrypted) { + /* + * The "decrypted" flag being true assumes that set_memory_decrypted() succeeds. + * But if it fails, the encryption state of the memory is unknown. In that case, + * leave "decrypted" as true to ensure the memory is leaked instead of going back + * on the free list. + */ + ret = set_memory_decrypted((unsigned long)kbuffer, + PFN_UP(size)); + if (ret) { + dev_warn(&channel->device_obj->device, + "Failed to set host visibility for new GPADL %d.\n", + ret); + vmbus_free_channel_msginfo(msginfo); + return ret; + } + } + + init_completion(&msginfo->waitevent); + msginfo->waiting_channel = channel; + + gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg; + gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER; + gpadlmsg->child_relid = channel->offermsg.child_relid; + gpadlmsg->gpadl = next_gpadl_handle; + + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_add_tail(&msginfo->msglistentry, + &vmbus_connection.chn_msg_list); + + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (channel->rescind) { + ret = -ENODEV; + goto cleanup; + } + + ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize - + sizeof(*msginfo), true); + + trace_vmbus_establish_gpadl_header(gpadlmsg, ret); + + if (ret != 0) + goto cleanup; + + list_for_each(curr, &msginfo->submsglist) { + submsginfo = (struct vmbus_channel_msginfo *)curr; + gpadl_body = + (struct vmbus_channel_gpadl_body *)submsginfo->msg; + + gpadl_body->header.msgtype = + CHANNELMSG_GPADL_BODY; + gpadl_body->gpadl = next_gpadl_handle; + + ret = vmbus_post_msg(gpadl_body, + submsginfo->msgsize - sizeof(*submsginfo), + true); + + trace_vmbus_establish_gpadl_body(gpadl_body, ret); + + if (ret != 0) + goto cleanup; + + } + wait_for_completion(&msginfo->waitevent); + + if (msginfo->response.gpadl_created.creation_status != 0) { + pr_err("Failed to establish GPADL: err = 0x%x\n", + msginfo->response.gpadl_created.creation_status); + + ret = -EDQUOT; + goto cleanup; + } + + if (channel->rescind) { + ret = -ENODEV; + goto cleanup; + } + + /* At this point, we received the gpadl created msg */ + gpadl->gpadl_handle = gpadlmsg->gpadl; + gpadl->buffer = kbuffer; + gpadl->size = size; + + +cleanup: + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&msginfo->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + vmbus_free_channel_msginfo(msginfo); + + if (ret) { + /* + * If set_memory_encrypted() fails, the decrypted flag is + * left as true so the memory is leaked instead of being + * put back on the free list. + */ + if (gpadl->decrypted) { + if (!set_memory_encrypted((unsigned long)kbuffer, PFN_UP(size))) + gpadl->decrypted = false; + } + } + + return ret; +} + +/* + * vmbus_establish_gpadl - Establish a GPADL for the specified buffer + * + * @channel: a channel + * @kbuffer: from kmalloc or vmalloc + * @size: page-size multiple + * @gpadl: output gpadl + */ +int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer, + u32 size, struct vmbus_gpadl *gpadl) +{ + return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size, + 0U, gpadl); +} +EXPORT_SYMBOL_GPL(vmbus_establish_gpadl); + +/* + * vmbus_establish_gpadl_caller_decrypted - Establish a GPADL for a buffer + * that has already been decrypted by the caller. + * + * @channel: a channel + * @kbuffer: from kmalloc or vmalloc; must already be decrypted by the caller + * @size: page-size multiple + * @gpadl: output gpadl + * + * The caller is responsible for re-encrypting the buffer before freeing it. + */ +int vmbus_establish_gpadl_caller_decrypted(struct vmbus_channel *channel, + void *kbuffer, u32 size, + struct vmbus_gpadl *gpadl) +{ + return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER_DECRYPTED, + kbuffer, size, 0U, gpadl); +} +EXPORT_SYMBOL_GPL(vmbus_establish_gpadl_caller_decrypted); + +/** + * vmbus_free_buffer - release a buffer allocated by vmbus_alloc_buffer(). + * + * @addr: buffer address, or NULL if none was allocated (e.g. cleanup from a + * failed allocation) + * @chunks: chunks array from vmbus_alloc_buffer(), or NULL + * @chunk_cnt: number of entries in @chunks + * + * When @chunks is NULL the buffer is a plain vzalloc() allocation. + * + * Otherwise tear down the vmap, and for each chunk re-encrypt and free + * the underlying pages. Any chunk that cannot be re-encrypted is leaked. + */ +void vmbus_free_buffer(void *addr, struct page **chunks, u32 chunk_cnt) +{ + u32 i; + + if (!chunks) { + vfree(addr); + return; + } + + vunmap(addr); + + for (i = 0; i < chunk_cnt; i++) { + unsigned long vaddr = + (unsigned long)page_address(chunks[i]); + unsigned int order = folio_order(page_folio(chunks[i])); + + if (set_memory_encrypted(vaddr, 1U << order)) + continue; + __free_pages(chunks[i], order); + } + + kvfree(chunks); +} +EXPORT_SYMBOL_GPL(vmbus_free_buffer); + +/** + * vmbus_alloc_buffer - allocate a host-visible, virtually-contiguous buffer. + * + * @channel: the channel the buffer will be attached to + * @size: requested buffer size in bytes (will be rounded up to PAGE_SIZE) + * @chunks_out: on success, set to the array of underlying chunks, or NULL when + * the buffer was allocated with vzalloc() + * @chunk_cnt_out: on success, set to the number of chunks + * + * Buffers not requiring decryption are allocated with vzalloc(). + * + * Buffers requiring decryption are allocated as a series of + * physically-contiguous chunks, starting at MAX_PAGE_ORDER and falling back to + * smaller orders on allocation failure. Each chunk is transitioned to + * host-visible via set_memory_decrypted() on its direct-map address, then all + * chunks are combined into a virtually-contiguous range via vmap(). + * + * Return: the buffer's virtual address, or NULL on failure. + */ +void *vmbus_alloc_buffer(struct vmbus_channel *channel, + u32 size, + struct page ***chunks_out, + u32 *chunk_cnt_out) +{ + unsigned long nr_pages = PFN_UP(size); + unsigned long remaining = nr_pages; + unsigned long page_idx = 0; + struct page **chunks = NULL; + struct page **pages = NULL; + int order = MAX_PAGE_ORDER; + u32 chunk_cnt = 0; + void *addr; + u32 i; + int ret; + + *chunks_out = NULL; + *chunk_cnt_out = 0; + + if (!nr_pages) + return NULL; + + /* If the buffer does not need to be decrypted, just use vzalloc() */ + if (!hv_is_isolation_supported() || channel->co_external_memory) + return vzalloc(nr_pages << PAGE_SHIFT); + + /* Worst case: every chunk is a single page. */ + chunks = kvmalloc_objs(*chunks, nr_pages, GFP_KERNEL | __GFP_ZERO); + if (!chunks) + goto err; + + pages = kvmalloc_objs(*pages, nr_pages); + if (!pages) + goto err; + + while (remaining) { + struct page *page; + gfp_t gfp; + + order = min(order, ilog2(remaining)); + + /* + * Use __GFP_NORETRY | __GFP_NOWARN to avoid OOM-killing, + * but try harder at order 0 since that is the final + * fallback. + * __GFP_COMP stores order information in the page folio. + */ + gfp = GFP_KERNEL | __GFP_ZERO; + if (order) + gfp |= __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN; + + page = alloc_pages_node(cpu_to_node(channel->target_cpu), + gfp, order); + if (!page) { + if (!order--) + goto err; + continue; + } + + ret = set_memory_decrypted((unsigned long)page_address(page), + 1U << order); + if (ret) { + /* + * set_memory_decrypted() failed; the page state is + * unknown so it must be leaked rather than freed. + */ + goto err; + } + + chunks[chunk_cnt++] = page; + + for (i = 0; i < (1U << order); i++) + pages[page_idx++] = page + i; + + remaining -= 1U << order; + } + + addr = vmap(pages, nr_pages, VM_MAP, pgprot_decrypted(PAGE_KERNEL)); + if (!addr) + goto err; + + memset(addr, 0, nr_pages << PAGE_SHIFT); + + kvfree(pages); + *chunks_out = chunks; + *chunk_cnt_out = chunk_cnt; + return addr; + +err: + kvfree(pages); + vmbus_free_buffer(NULL, chunks, chunk_cnt); + return NULL; +} +EXPORT_SYMBOL_GPL(vmbus_alloc_buffer); + +/** + * request_arr_init - Allocates memory for the requestor array. Each slot + * keeps track of the next available slot in the array. Initially, each + * slot points to the next one (as in a Linked List). The last slot + * does not point to anything, so its value is U64_MAX by default. + * @size: The size of the array + */ +static u64 *request_arr_init(u32 size) +{ + int i; + u64 *req_arr; + + req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL); + if (!req_arr) + return NULL; + + for (i = 0; i < size - 1; i++) + req_arr[i] = i + 1; + + /* Last slot (no more available slots) */ + req_arr[i] = U64_MAX; + + return req_arr; +} + +/* + * vmbus_alloc_requestor - Initializes @rqstor's fields. + * Index 0 is the first free slot + * @size: Size of the requestor array + */ +static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size) +{ + u64 *rqst_arr; + unsigned long *bitmap; + + rqst_arr = request_arr_init(size); + if (!rqst_arr) + return -ENOMEM; + + bitmap = bitmap_zalloc(size, GFP_KERNEL); + if (!bitmap) { + kfree(rqst_arr); + return -ENOMEM; + } + + rqstor->req_arr = rqst_arr; + rqstor->req_bitmap = bitmap; + rqstor->size = size; + rqstor->next_request_id = 0; + spin_lock_init(&rqstor->req_lock); + + return 0; +} + +/* + * vmbus_free_requestor - Frees memory allocated for @rqstor + * @rqstor: Pointer to the requestor struct + */ +static void vmbus_free_requestor(struct vmbus_requestor *rqstor) +{ + kfree(rqstor->req_arr); + bitmap_free(rqstor->req_bitmap); +} + +static int __vmbus_open(struct vmbus_channel *newchannel, + void *userdata, u32 userdatalen, + void (*onchannelcallback)(void *context), void *context) +{ + struct vmbus_channel_open_channel *open_msg; + struct vmbus_channel_msginfo *open_info = NULL; + struct page *page = newchannel->ringbuffer_page; + u32 send_pages, recv_pages; + unsigned long flags; + int err; + + if (userdatalen > MAX_USER_DEFINED_BYTES) + return -EINVAL; + + send_pages = newchannel->ringbuffer_send_offset; + recv_pages = newchannel->ringbuffer_pagecount - send_pages; + + if (newchannel->state != CHANNEL_OPEN_STATE) + return -EINVAL; + + /* Create and init requestor */ + if (newchannel->rqstor_size) { + if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size)) + return -ENOMEM; + } + + newchannel->state = CHANNEL_OPENING_STATE; + newchannel->onchannel_callback = onchannelcallback; + newchannel->channel_callback_context = context; + + if (!newchannel->max_pkt_size) + newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE; + + /* Establish the gpadl for the ring buffer */ + newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0; + + err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING, + page_address(newchannel->ringbuffer_page), + (send_pages + recv_pages) << PAGE_SHIFT, + newchannel->ringbuffer_send_offset << PAGE_SHIFT, + &newchannel->ringbuffer_gpadlhandle); + if (err) + goto error_clean_ring; + + err = hv_ringbuffer_init(&newchannel->outbound, + page, send_pages, 0, newchannel->co_ring_buffer); + if (err) + goto error_free_gpadl; + + err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages], + recv_pages, newchannel->max_pkt_size, + newchannel->co_ring_buffer); + if (err) + goto error_free_gpadl; + + /* Create and init the channel open message */ + open_info = kzalloc(sizeof(*open_info) + + sizeof(struct vmbus_channel_open_channel), + GFP_KERNEL); + if (!open_info) { + err = -ENOMEM; + goto error_free_gpadl; + } + + init_completion(&open_info->waitevent); + open_info->waiting_channel = newchannel; + + open_msg = (struct vmbus_channel_open_channel *)open_info->msg; + open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL; + open_msg->openid = newchannel->offermsg.child_relid; + open_msg->child_relid = newchannel->offermsg.child_relid; + open_msg->ringbuffer_gpadlhandle + = newchannel->ringbuffer_gpadlhandle.gpadl_handle; + /* + * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and + * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so + * here we calculate it into HV_HYP_PAGE. + */ + open_msg->downstream_ringbuffer_pageoffset = + hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT); + open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu); + + if (userdatalen) + memcpy(open_msg->userdata, userdata, userdatalen); + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_add_tail(&open_info->msglistentry, + &vmbus_connection.chn_msg_list); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (newchannel->rescind) { + err = -ENODEV; + goto error_clean_msglist; + } + + err = vmbus_post_msg(open_msg, + sizeof(struct vmbus_channel_open_channel), true); + + trace_vmbus_open(open_msg, err); + + if (err != 0) + goto error_clean_msglist; + + wait_for_completion(&open_info->waitevent); + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&open_info->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (newchannel->rescind) { + err = -ENODEV; + goto error_free_info; + } + + if (open_info->response.open_result.status) { + err = -EAGAIN; + goto error_free_info; + } + + newchannel->state = CHANNEL_OPENED_STATE; + kfree(open_info); + return 0; + +error_clean_msglist: + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&open_info->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +error_free_info: + kfree(open_info); +error_free_gpadl: + vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle); +error_clean_ring: + hv_ringbuffer_cleanup(&newchannel->outbound); + hv_ringbuffer_cleanup(&newchannel->inbound); + vmbus_free_requestor(&newchannel->requestor); + newchannel->state = CHANNEL_OPEN_STATE; + return err; +} + +/* + * vmbus_connect_ring - Open the channel but reuse ring buffer + */ +int vmbus_connect_ring(struct vmbus_channel *newchannel, + void (*onchannelcallback)(void *context), void *context) +{ + return __vmbus_open(newchannel, NULL, 0, onchannelcallback, context); +} +EXPORT_SYMBOL_GPL(vmbus_connect_ring); + +/* + * vmbus_open - Open the specified channel. + */ +int vmbus_open(struct vmbus_channel *newchannel, + u32 send_ringbuffer_size, u32 recv_ringbuffer_size, + void *userdata, u32 userdatalen, + void (*onchannelcallback)(void *context), void *context) +{ + int err; + + err = vmbus_alloc_ring(newchannel, send_ringbuffer_size, + recv_ringbuffer_size); + if (err) + return err; + + err = __vmbus_open(newchannel, userdata, userdatalen, + onchannelcallback, context); + if (err) + vmbus_free_ring(newchannel); + + return err; +} +EXPORT_SYMBOL_GPL(vmbus_open); + +/* + * vmbus_teardown_gpadl -Teardown the specified GPADL handle + */ +int vmbus_teardown_gpadl(struct vmbus_channel *channel, struct vmbus_gpadl *gpadl) +{ + struct vmbus_channel_gpadl_teardown *msg; + struct vmbus_channel_msginfo *info; + unsigned long flags; + int ret; + + info = kzalloc(sizeof(*info) + + sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL); + if (!info) + return -ENOMEM; + + init_completion(&info->waitevent); + info->waiting_channel = channel; + + msg = (struct vmbus_channel_gpadl_teardown *)info->msg; + + msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN; + msg->child_relid = channel->offermsg.child_relid; + msg->gpadl = gpadl->gpadl_handle; + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_add_tail(&info->msglistentry, + &vmbus_connection.chn_msg_list); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (channel->rescind) + goto post_msg_err; + + ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown), + true); + + trace_vmbus_teardown_gpadl(msg, ret); + + if (ret) + goto post_msg_err; + + wait_for_completion(&info->waitevent); + + gpadl->gpadl_handle = 0; + +post_msg_err: + /* + * If the channel has been rescinded; + * we will be awakened by the rescind + * handler; set the error code to zero so we don't leak memory. + */ + if (channel->rescind) + ret = 0; + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + list_del(&info->msglistentry); + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + kfree(info); + + if (gpadl->decrypted) + ret = set_memory_encrypted((unsigned long)gpadl->buffer, + PFN_UP(gpadl->size)); + else + ret = 0; + if (ret) + pr_warn("Fail to set mem host visibility in GPADL teardown %d.\n", ret); + + gpadl->decrypted = ret; + + return ret; +} +EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl); + +void vmbus_reset_channel_cb(struct vmbus_channel *channel) +{ + unsigned long flags; + + /* + * vmbus_on_event(), running in the per-channel tasklet, can race + * with vmbus_close_internal() in the case of SMP guest, e.g., when + * the former is accessing channel->inbound.ring_buffer, the latter + * could be freeing the ring_buffer pages, so here we must stop it + * first. + * + * vmbus_chan_sched() might call the netvsc driver callback function + * that ends up scheduling NAPI work that accesses the ring buffer. + * At this point, we have to ensure that any such work is completed + * and that the channel ring buffer is no longer being accessed, cf. + * the calls to napi_disable() in netvsc_device_remove(). + */ + tasklet_disable(&channel->callback_event); + + /* See the inline comments in vmbus_chan_sched(). */ + spin_lock_irqsave(&channel->sched_lock, flags); + channel->onchannel_callback = NULL; + spin_unlock_irqrestore(&channel->sched_lock, flags); + + channel->sc_creation_callback = NULL; + + /* Re-enable tasklet for use on re-open */ + tasklet_enable(&channel->callback_event); +} + +static int vmbus_close_internal(struct vmbus_channel *channel) +{ + struct vmbus_channel_close_channel *msg; + int ret; + + vmbus_reset_channel_cb(channel); + + /* + * In case a device driver's probe() fails (e.g., + * util_probe() -> vmbus_open() returns -ENOMEM) and the device is + * rescinded later (e.g., we dynamically disable an Integrated Service + * in Hyper-V Manager), the driver's remove() invokes vmbus_close(): + * here we should skip most of the below cleanup work. + */ + if (channel->state != CHANNEL_OPENED_STATE) + return -EINVAL; + + channel->state = CHANNEL_OPEN_STATE; + + /* Send a closing message */ + + msg = &channel->close_msg; + + msg->header.msgtype = CHANNELMSG_CLOSECHANNEL; + msg->child_relid = channel->offermsg.child_relid; + + ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel), + true); + + trace_vmbus_close_internal(msg, ret); + + if (ret) { + pr_err("Close failed: close post msg return is %d\n", ret); + /* + * If we failed to post the close msg, + * it is perhaps better to leak memory. + */ + } + + /* Tear down the gpadl for the channel's ring buffer */ + else if (channel->ringbuffer_gpadlhandle.gpadl_handle) { + ret = vmbus_teardown_gpadl(channel, &channel->ringbuffer_gpadlhandle); + if (ret) { + pr_err("Close failed: teardown gpadl return %d\n", ret); + /* + * If we failed to teardown gpadl, + * it is perhaps better to leak memory. + */ + } + } + + if (!ret) + vmbus_free_requestor(&channel->requestor); + + return ret; +} + +/* disconnect ring - close all channels */ +int vmbus_disconnect_ring(struct vmbus_channel *channel) +{ + struct vmbus_channel *cur_channel, *tmp; + int ret; + + if (channel->primary_channel != NULL) + return -EINVAL; + + list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) { + if (cur_channel->rescind) + wait_for_completion(&cur_channel->rescind_event); + + mutex_lock(&vmbus_connection.channel_mutex); + if (vmbus_close_internal(cur_channel) == 0) { + vmbus_free_ring(cur_channel); + + if (cur_channel->rescind) + hv_process_channel_removal(cur_channel); + } + mutex_unlock(&vmbus_connection.channel_mutex); + } + + /* + * Now close the primary. + */ + mutex_lock(&vmbus_connection.channel_mutex); + ret = vmbus_close_internal(channel); + mutex_unlock(&vmbus_connection.channel_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(vmbus_disconnect_ring); + +/* + * vmbus_close - Close the specified channel + */ +void vmbus_close(struct vmbus_channel *channel) +{ + if (vmbus_disconnect_ring(channel) == 0) + vmbus_free_ring(channel); +} +EXPORT_SYMBOL_GPL(vmbus_close); + +/** + * vmbus_sendpacket_getid() - Send the specified buffer on the given channel + * @channel: Pointer to vmbus_channel structure + * @buffer: Pointer to the buffer you want to send the data from. + * @bufferlen: Maximum size of what the buffer holds. + * @requestid: Identifier of the request + * @trans_id: Identifier of the transaction associated to this request, if + * the send is successful; undefined, otherwise. + * @type: Type of packet that is being sent e.g. negotiate, time + * packet etc. + * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED + * + * Sends data in @buffer directly to Hyper-V via the vmbus. + * This will send the data unparsed to Hyper-V. + * + * Mainly used by Hyper-V drivers. + */ +int vmbus_sendpacket_getid(struct vmbus_channel *channel, void *buffer, + u32 bufferlen, u64 requestid, u64 *trans_id, + enum vmbus_packet_type type, u32 flags) +{ + struct vmpacket_descriptor desc; + u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen; + u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64)); + struct kvec bufferlist[3]; + u64 aligned_data = 0; + int num_vecs = ((bufferlen != 0) ? 3 : 1); + + + /* Setup the descriptor */ + desc.type = type; /* VmbusPacketTypeDataInBand; */ + desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */ + /* in 8-bytes granularity */ + desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3; + desc.len8 = (u16)(packetlen_aligned >> 3); + desc.trans_id = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */ + + bufferlist[0].iov_base = &desc; + bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor); + bufferlist[1].iov_base = buffer; + bufferlist[1].iov_len = bufferlen; + bufferlist[2].iov_base = &aligned_data; + bufferlist[2].iov_len = (packetlen_aligned - packetlen); + + return hv_ringbuffer_write(channel, bufferlist, num_vecs, requestid, trans_id); +} +EXPORT_SYMBOL(vmbus_sendpacket_getid); + +/** + * vmbus_sendpacket() - Send the specified buffer on the given channel + * @channel: Pointer to vmbus_channel structure + * @buffer: Pointer to the buffer you want to send the data from. + * @bufferlen: Maximum size of what the buffer holds. + * @requestid: Identifier of the request + * @type: Type of packet that is being sent e.g. negotiate, time + * packet etc. + * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED + * + * Sends data in @buffer directly to Hyper-V via the vmbus. + * This will send the data unparsed to Hyper-V. + * + * Mainly used by Hyper-V drivers. + */ +int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer, + u32 bufferlen, u64 requestid, + enum vmbus_packet_type type, u32 flags) +{ + return vmbus_sendpacket_getid(channel, buffer, bufferlen, + requestid, NULL, type, flags); +} +EXPORT_SYMBOL(vmbus_sendpacket); + +/* + * vmbus_sendpacket_mpb_desc - Send one or more multi-page buffer packets + * using a GPADL Direct packet type. + * The desc argument must include space for the VMBus descriptor. The + * rangecount field must already be set. + */ +int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel, + struct vmbus_packet_mpb_array *desc, + u32 desc_size, + void *buffer, u32 bufferlen, u64 requestid) +{ + u32 packetlen; + u32 packetlen_aligned; + struct kvec bufferlist[3]; + u64 aligned_data = 0; + + packetlen = desc_size + bufferlen; + packetlen_aligned = ALIGN(packetlen, sizeof(u64)); + + /* Setup the descriptor */ + desc->type = VM_PKT_DATA_USING_GPA_DIRECT; + desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; + desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */ + desc->length8 = (u16)(packetlen_aligned >> 3); + desc->transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */ + desc->reserved = 0; + + bufferlist[0].iov_base = desc; + bufferlist[0].iov_len = desc_size; + bufferlist[1].iov_base = buffer; + bufferlist[1].iov_len = bufferlen; + bufferlist[2].iov_base = &aligned_data; + bufferlist[2].iov_len = (packetlen_aligned - packetlen); + + return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL); +} +EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc); + +/** + * __vmbus_recvpacket() - Retrieve the user packet on the specified channel + * @channel: Pointer to vmbus_channel structure + * @buffer: Pointer to the buffer you want to receive the data into. + * @bufferlen: Maximum size of what the buffer can hold. + * @buffer_actual_len: The actual size of the data after it was received. + * @requestid: Identifier of the request + * @raw: true means keep the vmpacket_descriptor header in the received data. + * + * Receives directly from the hyper-v vmbus and puts the data it received + * into Buffer. This will receive the data unparsed from hyper-v. + * + * Mainly used by Hyper-V drivers. + */ +static inline int +__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, + u32 bufferlen, u32 *buffer_actual_len, u64 *requestid, + bool raw) +{ + return hv_ringbuffer_read(channel, buffer, bufferlen, + buffer_actual_len, requestid, raw); + +} + +int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, + u32 bufferlen, u32 *buffer_actual_len, + u64 *requestid) +{ + return __vmbus_recvpacket(channel, buffer, bufferlen, + buffer_actual_len, requestid, false); +} +EXPORT_SYMBOL(vmbus_recvpacket); + +/* + * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel + */ +int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer, + u32 bufferlen, u32 *buffer_actual_len, + u64 *requestid) +{ + return __vmbus_recvpacket(channel, buffer, bufferlen, + buffer_actual_len, requestid, true); +} +EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw); + +/* + * vmbus_next_request_id - Returns a new request id. It is also + * the index at which the guest memory address is stored. + * Uses a spin lock to avoid race conditions. + * @channel: Pointer to the VMbus channel struct + * @rqst_add: Guest memory address to be stored in the array + */ +u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) +{ + struct vmbus_requestor *rqstor = &channel->requestor; + unsigned long flags; + u64 current_id; + + /* Check rqstor has been initialized */ + if (!channel->rqstor_size) + return VMBUS_NO_RQSTOR; + + lock_requestor(channel, flags); + current_id = rqstor->next_request_id; + + /* Requestor array is full */ + if (current_id >= rqstor->size) { + unlock_requestor(channel, flags); + return VMBUS_RQST_ERROR; + } + + rqstor->next_request_id = rqstor->req_arr[current_id]; + rqstor->req_arr[current_id] = rqst_addr; + + /* The already held spin lock provides atomicity */ + bitmap_set(rqstor->req_bitmap, current_id, 1); + + unlock_requestor(channel, flags); + + /* + * Cannot return an ID of 0, which is reserved for an unsolicited + * message from Hyper-V; Hyper-V does not acknowledge (respond to) + * VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED requests with ID of + * 0 sent by the guest. + */ + return current_id + 1; +} +EXPORT_SYMBOL_GPL(vmbus_next_request_id); + +/* As in vmbus_request_addr_match() but without the requestor lock */ +u64 __vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id, + u64 rqst_addr) +{ + struct vmbus_requestor *rqstor = &channel->requestor; + u64 req_addr; + + /* Check rqstor has been initialized */ + if (!channel->rqstor_size) + return VMBUS_NO_RQSTOR; + + /* Hyper-V can send an unsolicited message with ID of 0 */ + if (!trans_id) + return VMBUS_RQST_ERROR; + + /* Data corresponding to trans_id is stored at trans_id - 1 */ + trans_id--; + + /* Invalid trans_id */ + if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) + return VMBUS_RQST_ERROR; + + req_addr = rqstor->req_arr[trans_id]; + if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) { + rqstor->req_arr[trans_id] = rqstor->next_request_id; + rqstor->next_request_id = trans_id; + + /* The already held spin lock provides atomicity */ + bitmap_clear(rqstor->req_bitmap, trans_id, 1); + } + + return req_addr; +} +EXPORT_SYMBOL_GPL(__vmbus_request_addr_match); + +/* + * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's + * requestor, provided the memory address stored at @trans_id equals @rqst_addr + * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY). + * + * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if + * @trans_id is not contained in the requestor. + * + * Acquires and releases the requestor spin lock. + */ +u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id, + u64 rqst_addr) +{ + unsigned long flags; + u64 req_addr; + + lock_requestor(channel, flags); + req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr); + unlock_requestor(channel, flags); + + return req_addr; +} +EXPORT_SYMBOL_GPL(vmbus_request_addr_match); + +/* + * vmbus_request_addr - Returns the memory address stored at @trans_id + * in @rqstor. Uses a spin lock to avoid race conditions. + * @channel: Pointer to the VMbus channel struct + * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's + * next request id. + */ +u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) +{ + return vmbus_request_addr_match(channel, trans_id, VMBUS_RQST_ADDR_ANY); +} +EXPORT_SYMBOL_GPL(vmbus_request_addr); |