/* * vhost support * * Copyright Red Hat, Inc. 2010 * * Authors: * Michael S. Tsirkin * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include "qemu/osdep.h" #include "qapi/error.h" #include "hw/virtio/vhost.h" #include "qemu/atomic.h" #include "qemu/range.h" #include "qemu/error-report.h" #include "qemu/memfd.h" #include "qemu/log.h" #include "standard-headers/linux/vhost_types.h" #include "hw/virtio/virtio-bus.h" #include "hw/mem/memory-device.h" #include "migration/blocker.h" #include "migration/qemu-file-types.h" #include "sysemu/dma.h" #include "trace.h" /* enabled until disconnected backend stabilizes */ #define _VHOST_DEBUG 1 #ifdef _VHOST_DEBUG #define VHOST_OPS_DEBUG(retval, fmt, ...) \ do { \ error_report(fmt ": %s (%d)", ## __VA_ARGS__, \ strerror(-retval), -retval); \ } while (0) #else #define VHOST_OPS_DEBUG(retval, fmt, ...) \ do { } while (0) #endif static struct vhost_log *vhost_log[VHOST_BACKEND_TYPE_MAX]; static struct vhost_log *vhost_log_shm[VHOST_BACKEND_TYPE_MAX]; static QLIST_HEAD(, vhost_dev) vhost_log_devs[VHOST_BACKEND_TYPE_MAX]; /* Memslots used by backends that support private memslots (without an fd). */ static unsigned int used_memslots; /* Memslots used by backends that only support shared memslots (with an fd). */ static unsigned int used_shared_memslots; static QLIST_HEAD(, vhost_dev) vhost_devices = QLIST_HEAD_INITIALIZER(vhost_devices); unsigned int vhost_get_max_memslots(void) { unsigned int max = UINT_MAX; struct vhost_dev *hdev; QLIST_FOREACH(hdev, &vhost_devices, entry) { max = MIN(max, hdev->vhost_ops->vhost_backend_memslots_limit(hdev)); } return max; } unsigned int vhost_get_free_memslots(void) { unsigned int free = UINT_MAX; struct vhost_dev *hdev; QLIST_FOREACH(hdev, &vhost_devices, entry) { unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev); unsigned int cur_free; if (hdev->vhost_ops->vhost_backend_no_private_memslots && hdev->vhost_ops->vhost_backend_no_private_memslots(hdev)) { cur_free = r - used_shared_memslots; } else { cur_free = r - used_memslots; } free = MIN(free, cur_free); } return free; } static void vhost_dev_sync_region(struct vhost_dev *dev, MemoryRegionSection *section, uint64_t mfirst, uint64_t mlast, uint64_t rfirst, uint64_t rlast) { vhost_log_chunk_t *dev_log = dev->log->log; uint64_t start = MAX(mfirst, rfirst); uint64_t end = MIN(mlast, rlast); vhost_log_chunk_t *from = dev_log + start / VHOST_LOG_CHUNK; vhost_log_chunk_t *to = dev_log + end / VHOST_LOG_CHUNK + 1; uint64_t addr = QEMU_ALIGN_DOWN(start, VHOST_LOG_CHUNK); if (end < start) { return; } assert(end / VHOST_LOG_CHUNK < dev->log_size); assert(start / VHOST_LOG_CHUNK < dev->log_size); for (;from < to; ++from) { vhost_log_chunk_t log; /* We first check with non-atomic: much cheaper, * and we expect non-dirty to be the common case. */ if (!*from) { addr += VHOST_LOG_CHUNK; continue; } /* Data must be read atomically. We don't really need barrier semantics * but it's easier to use atomic_* than roll our own. */ log = qatomic_xchg(from, 0); while (log) { int bit = ctzl(log); hwaddr page_addr; hwaddr section_offset; hwaddr mr_offset; page_addr = addr + bit * VHOST_LOG_PAGE; section_offset = page_addr - section->offset_within_address_space; mr_offset = section_offset + section->offset_within_region; memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE); log &= ~(0x1ull << bit); } addr += VHOST_LOG_CHUNK; } } bool vhost_dev_has_iommu(struct vhost_dev *dev) { VirtIODevice *vdev = dev->vdev; /* * For vhost, VIRTIO_F_IOMMU_PLATFORM means the backend support * incremental memory mapping API via IOTLB API. For platform that * does not have IOMMU, there's no need to enable this feature * which may cause unnecessary IOTLB miss/update transactions. */ if (vdev) { return virtio_bus_device_iommu_enabled(vdev) && virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM); } else { return false; } } static inline bool vhost_dev_should_log(struct vhost_dev *dev) { assert(dev->vhost_ops); assert(dev->vhost_ops->backend_type > VHOST_BACKEND_TYPE_NONE); assert(dev->vhost_ops->backend_type < VHOST_BACKEND_TYPE_MAX); return dev == QLIST_FIRST(&vhost_log_devs[dev->vhost_ops->backend_type]); } static inline void vhost_dev_elect_mem_logger(struct vhost_dev *hdev, bool add) { VhostBackendType backend_type; assert(hdev->vhost_ops); backend_type = hdev->vhost_ops->backend_type; assert(backend_type > VHOST_BACKEND_TYPE_NONE); assert(backend_type < VHOST_BACKEND_TYPE_MAX); if (add && !QLIST_IS_INSERTED(hdev, logdev_entry)) { if (QLIST_EMPTY(&vhost_log_devs[backend_type])) { QLIST_INSERT_HEAD(&vhost_log_devs[backend_type], hdev, logdev_entry); } else { /* * The first vhost_device in the list is selected as the shared * logger to scan memory sections. Put new entry next to the head * to avoid inadvertent change to the underlying logger device. * This is done in order to get better cache locality and to avoid * performance churn on the hot path for log scanning. Even when * new devices come and go quickly, it wouldn't end up changing * the active leading logger device at all. */ QLIST_INSERT_AFTER(QLIST_FIRST(&vhost_log_devs[backend_type]), hdev, logdev_entry); } } else if (!add && QLIST_IS_INSERTED(hdev, logdev_entry)) { QLIST_REMOVE(hdev, logdev_entry); } } static int vhost_sync_dirty_bitmap(struct vhost_dev *dev, MemoryRegionSection *section, hwaddr first, hwaddr last) { int i; hwaddr start_addr; hwaddr end_addr; if (!dev->log_enabled || !dev->started) { return 0; } start_addr = section->offset_within_address_space; end_addr = range_get_last(start_addr, int128_get64(section->size)); start_addr = MAX(first, start_addr); end_addr = MIN(last, end_addr); if (vhost_dev_should_log(dev)) { for (i = 0; i < dev->mem->nregions; ++i) { struct vhost_memory_region *reg = dev->mem->regions + i; vhost_dev_sync_region(dev, section, start_addr, end_addr, reg->guest_phys_addr, range_get_last(reg->guest_phys_addr, reg->memory_size)); } } for (i = 0; i < dev->nvqs; ++i) { struct vhost_virtqueue *vq = dev->vqs + i; if (!vq->used_phys && !vq->used_size) { continue; } if (vhost_dev_has_iommu(dev)) { IOMMUTLBEntry iotlb; hwaddr used_phys = vq->used_phys, used_size = vq->used_size; hwaddr phys, s, offset; while (used_size) { rcu_read_lock(); iotlb = address_space_get_iotlb_entry(dev->vdev->dma_as, used_phys, true, MEMTXATTRS_UNSPECIFIED); rcu_read_unlock(); if (!iotlb.target_as) { qemu_log_mask(LOG_GUEST_ERROR, "translation " "failure for used_iova %"PRIx64"\n", used_phys); return -EINVAL; } offset = used_phys & iotlb.addr_mask; phys = iotlb.translated_addr + offset; /* * Distance from start of used ring until last byte of * IOMMU page. */ s = iotlb.addr_mask - offset; /* * Size of used ring, or of the part of it until end * of IOMMU page. To avoid zero result, do the adding * outside of MIN(). */ s = MIN(s, used_size - 1) + 1; vhost_dev_sync_region(dev, section, start_addr, end_addr, phys, range_get_last(phys, s)); used_size -= s; used_phys += s; } } else { vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys, range_get_last(vq->used_phys, vq->used_size)); } } return 0; } static void vhost_log_sync(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL); } static void vhost_log_sync_range(struct vhost_dev *dev, hwaddr first, hwaddr last) { int i; /* FIXME: this is N^2 in number of sections */ for (i = 0; i < dev->n_mem_sections; ++i) { MemoryRegionSection *section = &dev->mem_sections[i]; vhost_sync_dirty_bitmap(dev, section, first, last); } } static uint64_t vhost_get_log_size(struct vhost_dev *dev) { uint64_t log_size = 0; int i; for (i = 0; i < dev->mem->nregions; ++i) { struct vhost_memory_region *reg = dev->mem->regions + i; uint64_t last = range_get_last(reg->guest_phys_addr, reg->memory_size); log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); } return log_size; } static int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type) { int r = 0; switch (backend_type) { #ifdef CONFIG_VHOST_KERNEL case VHOST_BACKEND_TYPE_KERNEL: dev->vhost_ops = &kernel_ops; break; #endif #ifdef CONFIG_VHOST_USER case VHOST_BACKEND_TYPE_USER: dev->vhost_ops = &user_ops; break; #endif #ifdef CONFIG_VHOST_VDPA case VHOST_BACKEND_TYPE_VDPA: dev->vhost_ops = &vdpa_ops; break; #endif default: error_report("Unknown vhost backend type"); r = -1; } if (r == 0) { assert(dev->vhost_ops->backend_type == backend_type); } return r; } static struct vhost_log *vhost_log_alloc(uint64_t size, bool share) { Error *err = NULL; struct vhost_log *log; uint64_t logsize = size * sizeof(*(log->log)); int fd = -1; log = g_new0(struct vhost_log, 1); if (share) { log->log = qemu_memfd_alloc("vhost-log", logsize, F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL, &fd, &err); if (err) { error_report_err(err); g_free(log); return NULL; } memset(log->log, 0, logsize); } else { log->log = g_malloc0(logsize); } log->size = size; log->refcnt = 1; log->fd = fd; return log; } static struct vhost_log *vhost_log_get(VhostBackendType backend_type, uint64_t size, bool share) { struct vhost_log *log; assert(backend_type > VHOST_BACKEND_TYPE_NONE); assert(backend_type < VHOST_BACKEND_TYPE_MAX); log = share ? vhost_log_shm[backend_type] : vhost_log[backend_type]; if (!log || log->size != size) { log = vhost_log_alloc(size, share); if (share) { vhost_log_shm[backend_type] = log; } else { vhost_log[backend_type] = log; } } else { ++log->refcnt; } return log; } static void vhost_log_put(struct vhost_dev *dev, bool sync) { struct vhost_log *log = dev->log; VhostBackendType backend_type; if (!log) { return; } assert(dev->vhost_ops); backend_type = dev->vhost_ops->backend_type; if (backend_type == VHOST_BACKEND_TYPE_NONE || backend_type >= VHOST_BACKEND_TYPE_MAX) { return; } --log->refcnt; if (log->refcnt == 0) { /* Sync only the range covered by the old log */ if (dev->log_size && sync) { vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1); } if (vhost_log[backend_type] == log) { g_free(log->log); vhost_log[backend_type] = NULL; } else if (vhost_log_shm[backend_type] == log) { qemu_memfd_free(log->log, log->size * sizeof(*(log->log)), log->fd); vhost_log_shm[backend_type] = NULL; } g_free(log); } vhost_dev_elect_mem_logger(dev, false); dev->log = NULL; dev->log_size = 0; } static bool vhost_dev_log_is_shared(struct vhost_dev *dev) { return dev->vhost_ops->vhost_requires_shm_log && dev->vhost_ops->vhost_requires_shm_log(dev); } static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size) { struct vhost_log *log = vhost_log_get(dev->vhost_ops->backend_type, size, vhost_dev_log_is_shared(dev)); uint64_t log_base = (uintptr_t)log->log; int r; /* inform backend of log switching, this must be done before releasing the current log, to ensure no logging is lost */ r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_log_base failed"); } vhost_log_put(dev, true); dev->log = log; dev->log_size = size; } static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr, hwaddr *plen, bool is_write) { if (!vhost_dev_has_iommu(dev)) { return cpu_physical_memory_map(addr, plen, is_write); } else { return (void *)(uintptr_t)addr; } } static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer, hwaddr len, int is_write, hwaddr access_len) { if (!vhost_dev_has_iommu(dev)) { cpu_physical_memory_unmap(buffer, len, is_write, access_len); } } static int vhost_verify_ring_part_mapping(void *ring_hva, uint64_t ring_gpa, uint64_t ring_size, void *reg_hva, uint64_t reg_gpa, uint64_t reg_size) { uint64_t hva_ring_offset; uint64_t ring_last = range_get_last(ring_gpa, ring_size); uint64_t reg_last = range_get_last(reg_gpa, reg_size); if (ring_last < reg_gpa || ring_gpa > reg_last) { return 0; } /* check that whole ring's is mapped */ if (ring_last > reg_last) { return -ENOMEM; } /* check that ring's MemoryRegion wasn't replaced */ hva_ring_offset = ring_gpa - reg_gpa; if (ring_hva != reg_hva + hva_ring_offset) { return -EBUSY; } return 0; } static int vhost_verify_ring_mappings(struct vhost_dev *dev, void *reg_hva, uint64_t reg_gpa, uint64_t reg_size) { int i, j; int r = 0; const char *part_name[] = { "descriptor table", "available ring", "used ring" }; if (vhost_dev_has_iommu(dev)) { return 0; } for (i = 0; i < dev->nvqs; ++i) { struct vhost_virtqueue *vq = dev->vqs + i; if (vq->desc_phys == 0) { continue; } j = 0; r = vhost_verify_ring_part_mapping( vq->desc, vq->desc_phys, vq->desc_size, reg_hva, reg_gpa, reg_size); if (r) { break; } j++; r = vhost_verify_ring_part_mapping( vq->avail, vq->avail_phys, vq->avail_size, reg_hva, reg_gpa, reg_size); if (r) { break; } j++; r = vhost_verify_ring_part_mapping( vq->used, vq->used_phys, vq->used_size, reg_hva, reg_gpa, reg_size); if (r) { break; } } if (r == -ENOMEM) { error_report("Unable to map %s for ring %d", part_name[j], i); } else if (r == -EBUSY) { error_report("%s relocated for ring %d", part_name[j], i); } return r; } /* * vhost_section: identify sections needed for vhost access * * We only care about RAM sections here (where virtqueue and guest * internals accessed by virtio might live). */ static bool vhost_section(struct vhost_dev *dev, MemoryRegionSection *section) { MemoryRegion *mr = section->mr; if (memory_region_is_ram(mr) && !memory_region_is_rom(mr)) { uint8_t dirty_mask = memory_region_get_dirty_log_mask(mr); uint8_t handled_dirty; /* * Kernel based vhost doesn't handle any block which is doing * dirty-tracking other than migration for which it has * specific logging support. However for TCG the kernel never * gets involved anyway so we can also ignore it's * self-modiying code detection flags. However a vhost-user * client could still confuse a TCG guest if it re-writes * executable memory that has already been translated. */ handled_dirty = (1 << DIRTY_MEMORY_MIGRATION) | (1 << DIRTY_MEMORY_CODE); if (dirty_mask & ~handled_dirty) { trace_vhost_reject_section(mr->name, 1); return false; } /* * Some backends (like vhost-user) can only handle memory regions * that have an fd (can be mapped into a different process). Filter * the ones without an fd out, if requested. * * TODO: we might have to limit to MAP_SHARED as well. */ if (memory_region_get_fd(section->mr) < 0 && dev->vhost_ops->vhost_backend_no_private_memslots && dev->vhost_ops->vhost_backend_no_private_memslots(dev)) { trace_vhost_reject_section(mr->name, 2); return false; } trace_vhost_section(mr->name); return true; } else { trace_vhost_reject_section(mr->name, 3); return false; } } static void vhost_begin(MemoryListener *listener) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); dev->tmp_sections = NULL; dev->n_tmp_sections = 0; } static void vhost_commit(MemoryListener *listener) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); MemoryRegionSection *old_sections; int n_old_sections; uint64_t log_size; size_t regions_size; int r; int i; bool changed = false; /* Note we can be called before the device is started, but then * starting the device calls set_mem_table, so we need to have * built the data structures. */ old_sections = dev->mem_sections; n_old_sections = dev->n_mem_sections; dev->mem_sections = dev->tmp_sections; dev->n_mem_sections = dev->n_tmp_sections; if (dev->n_mem_sections != n_old_sections) { changed = true; } else { /* Same size, lets check the contents */ for (i = 0; i < n_old_sections; i++) { if (!MemoryRegionSection_eq(&old_sections[i], &dev->mem_sections[i])) { changed = true; break; } } } trace_vhost_commit(dev->started, changed); if (!changed) { goto out; } /* Rebuild the regions list from the new sections list */ regions_size = offsetof(struct vhost_memory, regions) + dev->n_mem_sections * sizeof dev->mem->regions[0]; dev->mem = g_realloc(dev->mem, regions_size); dev->mem->nregions = dev->n_mem_sections; if (dev->vhost_ops->vhost_backend_no_private_memslots && dev->vhost_ops->vhost_backend_no_private_memslots(dev)) { used_shared_memslots = dev->mem->nregions; } else { used_memslots = dev->mem->nregions; } for (i = 0; i < dev->n_mem_sections; i++) { struct vhost_memory_region *cur_vmr = dev->mem->regions + i; struct MemoryRegionSection *mrs = dev->mem_sections + i; cur_vmr->guest_phys_addr = mrs->offset_within_address_space; cur_vmr->memory_size = int128_get64(mrs->size); cur_vmr->userspace_addr = (uintptr_t)memory_region_get_ram_ptr(mrs->mr) + mrs->offset_within_region; cur_vmr->flags_padding = 0; } if (!dev->started) { goto out; } for (i = 0; i < dev->mem->nregions; i++) { if (vhost_verify_ring_mappings(dev, (void *)(uintptr_t)dev->mem->regions[i].userspace_addr, dev->mem->regions[i].guest_phys_addr, dev->mem->regions[i].memory_size)) { error_report("Verify ring failure on region %d", i); abort(); } } if (!dev->log_enabled) { r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed"); } goto out; } log_size = vhost_get_log_size(dev); /* We allocate an extra 4K bytes to log, * to reduce the * number of reallocations. */ #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log) /* To log more, must increase log size before table update. */ if (dev->log_size < log_size) { vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER); } r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed"); } /* To log less, can only decrease log size after table update. */ if (dev->log_size > log_size + VHOST_LOG_BUFFER) { vhost_dev_log_resize(dev, log_size); } out: /* Deref the old list of sections, this must happen _after_ the * vhost_set_mem_table to ensure the client isn't still using the * section we're about to unref. */ while (n_old_sections--) { memory_region_unref(old_sections[n_old_sections].mr); } g_free(old_sections); return; } /* Adds the section data to the tmp_section structure. * It relies on the listener calling us in memory address order * and for each region (via the _add and _nop methods) to * join neighbours. */ static void vhost_region_add_section(struct vhost_dev *dev, MemoryRegionSection *section) { bool need_add = true; uint64_t mrs_size = int128_get64(section->size); uint64_t mrs_gpa = section->offset_within_address_space; uintptr_t mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) + section->offset_within_region; RAMBlock *mrs_rb = section->mr->ram_block; trace_vhost_region_add_section(section->mr->name, mrs_gpa, mrs_size, mrs_host); if (dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER) { /* Round the section to it's page size */ /* First align the start down to a page boundary */ size_t mrs_page = qemu_ram_pagesize(mrs_rb); uint64_t alignage = mrs_host & (mrs_page - 1); if (alignage) { mrs_host -= alignage; mrs_size += alignage; mrs_gpa -= alignage; } /* Now align the size up to a page boundary */ alignage = mrs_size & (mrs_page - 1); if (alignage) { mrs_size += mrs_page - alignage; } trace_vhost_region_add_section_aligned(section->mr->name, mrs_gpa, mrs_size, mrs_host); } if (dev->n_tmp_sections && !section->unmergeable) { /* Since we already have at least one section, lets see if * this extends it; since we're scanning in order, we only * have to look at the last one, and the FlatView that calls * us shouldn't have overlaps. */ MemoryRegionSection *prev_sec = dev->tmp_sections + (dev->n_tmp_sections - 1); uint64_t prev_gpa_start = prev_sec->offset_within_address_space; uint64_t prev_size = int128_get64(prev_sec->size); uint64_t prev_gpa_end = range_get_last(prev_gpa_start, prev_size); uint64_t prev_host_start = (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) + prev_sec->offset_within_region; uint64_t prev_host_end = range_get_last(prev_host_start, prev_size); if (mrs_gpa <= (prev_gpa_end + 1)) { /* OK, looks like overlapping/intersecting - it's possible that * the rounding to page sizes has made them overlap, but they should * match up in the same RAMBlock if they do. */ if (mrs_gpa < prev_gpa_start) { error_report("%s:Section '%s' rounded to %"PRIx64 " prior to previous '%s' %"PRIx64, __func__, section->mr->name, mrs_gpa, prev_sec->mr->name, prev_gpa_start); /* A way to cleanly fail here would be better */ return; } /* Offset from the start of the previous GPA to this GPA */ size_t offset = mrs_gpa - prev_gpa_start; if (prev_host_start + offset == mrs_host && section->mr == prev_sec->mr && !prev_sec->unmergeable) { uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size); need_add = false; prev_sec->offset_within_address_space = MIN(prev_gpa_start, mrs_gpa); prev_sec->offset_within_region = MIN(prev_host_start, mrs_host) - (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr); prev_sec->size = int128_make64(max_end - MIN(prev_host_start, mrs_host)); trace_vhost_region_add_section_merge(section->mr->name, int128_get64(prev_sec->size), prev_sec->offset_within_address_space, prev_sec->offset_within_region); } else { /* adjoining regions are fine, but overlapping ones with * different blocks/offsets shouldn't happen */ if (mrs_gpa != prev_gpa_end + 1) { error_report("%s: Overlapping but not coherent sections " "at %"PRIx64, __func__, mrs_gpa); return; } } } } if (need_add) { ++dev->n_tmp_sections; dev->tmp_sections = g_renew(MemoryRegionSection, dev->tmp_sections, dev->n_tmp_sections); dev->tmp_sections[dev->n_tmp_sections - 1] = *section; /* The flatview isn't stable and we don't use it, making it NULL * means we can memcmp the list. */ dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL; memory_region_ref(section->mr); } } /* Used for both add and nop callbacks */ static void vhost_region_addnop(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); if (!vhost_section(dev, section)) { return; } vhost_region_add_section(dev, section); } static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) { struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n); struct vhost_dev *hdev = iommu->hdev; hwaddr iova = iotlb->iova + iommu->iommu_offset; if (vhost_backend_invalidate_device_iotlb(hdev, iova, iotlb->addr_mask + 1)) { error_report("Fail to invalidate device iotlb"); } } static void vhost_iommu_region_add(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, iommu_listener); struct vhost_iommu *iommu; Int128 end; int iommu_idx; IOMMUMemoryRegion *iommu_mr; if (!memory_region_is_iommu(section->mr)) { return; } iommu_mr = IOMMU_MEMORY_REGION(section->mr); iommu = g_malloc0(sizeof(*iommu)); end = int128_add(int128_make64(section->offset_within_region), section->size); end = int128_sub(end, int128_one()); iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr, MEMTXATTRS_UNSPECIFIED); iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify, dev->vdev->device_iotlb_enabled ? IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP, section->offset_within_region, int128_get64(end), iommu_idx); iommu->mr = section->mr; iommu->iommu_offset = section->offset_within_address_space - section->offset_within_region; iommu->hdev = dev; memory_region_register_iommu_notifier(section->mr, &iommu->n, &error_fatal); QLIST_INSERT_HEAD(&dev->iommu_list, iommu, iommu_next); /* TODO: can replay help performance here? */ } static void vhost_iommu_region_del(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, iommu_listener); struct vhost_iommu *iommu; if (!memory_region_is_iommu(section->mr)) { return; } QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) { if (iommu->mr == section->mr && iommu->n.start == section->offset_within_region) { memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n); QLIST_REMOVE(iommu, iommu_next); g_free(iommu); break; } } } void vhost_toggle_device_iotlb(VirtIODevice *vdev) { VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); struct vhost_dev *dev; struct vhost_iommu *iommu; if (vdev->vhost_started) { dev = vdc->get_vhost(vdev); } else { return; } QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) { memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n); iommu->n.notifier_flags = vdev->device_iotlb_enabled ? IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP; memory_region_register_iommu_notifier(iommu->mr, &iommu->n, &error_fatal); } } static int vhost_virtqueue_set_addr(struct vhost_dev *dev, struct vhost_virtqueue *vq, unsigned idx, bool enable_log) { struct vhost_vring_addr addr; int r; memset(&addr, 0, sizeof(struct vhost_vring_addr)); if (dev->vhost_ops->vhost_vq_get_addr) { r = dev->vhost_ops->vhost_vq_get_addr(dev, &addr, vq); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_vq_get_addr failed"); return r; } } else { addr.desc_user_addr = (uint64_t)(unsigned long)vq->desc; addr.avail_user_addr = (uint64_t)(unsigned long)vq->avail; addr.used_user_addr = (uint64_t)(unsigned long)vq->used; } addr.index = idx; addr.log_guest_addr = vq->used_phys; addr.flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0; r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_vring_addr failed"); } return r; } static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log) { uint64_t features = dev->acked_features; int r; if (enable_log) { features |= 0x1ULL << VHOST_F_LOG_ALL; } if (!vhost_dev_has_iommu(dev)) { features &= ~(0x1ULL << VIRTIO_F_IOMMU_PLATFORM); } if (dev->vhost_ops->vhost_force_iommu) { if (dev->vhost_ops->vhost_force_iommu(dev) == true) { features |= 0x1ULL << VIRTIO_F_IOMMU_PLATFORM; } } r = dev->vhost_ops->vhost_set_features(dev, features); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_features failed"); goto out; } if (dev->vhost_ops->vhost_set_backend_cap) { r = dev->vhost_ops->vhost_set_backend_cap(dev); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_backend_cap failed"); goto out; } } out: return r; } static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) { int r, i, idx; hwaddr addr; r = vhost_dev_set_features(dev, enable_log); if (r < 0) { goto err_features; } for (i = 0; i < dev->nvqs; ++i) { idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); addr = virtio_queue_get_desc_addr(dev->vdev, idx); if (!addr) { /* * The queue might not be ready for start. If this * is the case there is no reason to continue the process. * The similar logic is used by the vhost_virtqueue_start() * routine. */ continue; } r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, enable_log); if (r < 0) { goto err_vq; } } /* * At log start we select our vhost_device logger that will scan the * memory sections and skip for the others. This is possible because * the log is shared amongst all vhost devices for a given type of * backend. */ vhost_dev_elect_mem_logger(dev, enable_log); return 0; err_vq: for (; i >= 0; --i) { idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); addr = virtio_queue_get_desc_addr(dev->vdev, idx); if (!addr) { continue; } vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, dev->log_enabled); } vhost_dev_set_features(dev, dev->log_enabled); err_features: return r; } static int vhost_migration_log(MemoryListener *listener, bool enable) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); int r; if (enable == dev->log_enabled) { return 0; } if (!dev->started) { dev->log_enabled = enable; return 0; } r = 0; if (!enable) { r = vhost_dev_set_log(dev, false); if (r < 0) { goto check_dev_state; } vhost_log_put(dev, false); } else { vhost_dev_log_resize(dev, vhost_get_log_size(dev)); r = vhost_dev_set_log(dev, true); if (r < 0) { goto check_dev_state; } } check_dev_state: dev->log_enabled = enable; /* * vhost-user-* devices could change their state during log * initialization due to disconnect. So check dev state after * vhost communication. */ if (!dev->started) { /* * Since device is in the stopped state, it is okay for * migration. Return success. */ r = 0; } if (r) { /* An error occurred. */ dev->log_enabled = false; } return r; } static bool vhost_log_global_start(MemoryListener *listener, Error **errp) { int r; r = vhost_migration_log(listener, true); if (r < 0) { abort(); } return true; } static void vhost_log_global_stop(MemoryListener *listener) { int r; r = vhost_migration_log(listener, false); if (r < 0) { abort(); } } static void vhost_log_start(MemoryListener *listener, MemoryRegionSection *section, int old, int new) { /* FIXME: implement */ } static void vhost_log_stop(MemoryListener *listener, MemoryRegionSection *section, int old, int new) { /* FIXME: implement */ } /* The vhost driver natively knows how to handle the vrings of non * cross-endian legacy devices and modern devices. Only legacy devices * exposed to a bi-endian guest may require the vhost driver to use a * specific endianness. */ static inline bool vhost_needs_vring_endian(VirtIODevice *vdev) { if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { return false; } #if HOST_BIG_ENDIAN return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_LITTLE; #else return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG; #endif } static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev, bool is_big_endian, int vhost_vq_index) { int r; struct vhost_vring_state s = { .index = vhost_vq_index, .num = is_big_endian }; r = dev->vhost_ops->vhost_set_vring_endian(dev, &s); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_vring_endian failed"); } return r; } static int vhost_memory_region_lookup(struct vhost_dev *hdev, uint64_t gpa, uint64_t *uaddr, uint64_t *len) { int i; for (i = 0; i < hdev->mem->nregions; i++) { struct vhost_memory_region *reg = hdev->mem->regions + i; if (gpa >= reg->guest_phys_addr && reg->guest_phys_addr + reg->memory_size > gpa) { *uaddr = reg->userspace_addr + gpa - reg->guest_phys_addr; *len = reg->guest_phys_addr + reg->memory_size - gpa; return 0; } } return -EFAULT; } int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write) { IOMMUTLBEntry iotlb; uint64_t uaddr, len; int ret = -EFAULT; RCU_READ_LOCK_GUARD(); trace_vhost_iotlb_miss(dev, 1); iotlb = address_space_get_iotlb_entry(dev->vdev->dma_as, iova, write, MEMTXATTRS_UNSPECIFIED); if (iotlb.target_as != NULL) { ret = vhost_memory_region_lookup(dev, iotlb.translated_addr, &uaddr, &len); if (ret) { trace_vhost_iotlb_miss(dev, 3); error_report("Fail to lookup the translated address " "%"PRIx64, iotlb.translated_addr); goto out; } len = MIN(iotlb.addr_mask + 1, len); iova = iova & ~iotlb.addr_mask; ret = vhost_backend_update_device_iotlb(dev, iova, uaddr, len, iotlb.perm); if (ret) { trace_vhost_iotlb_miss(dev, 4); error_report("Fail to update device iotlb"); goto out; } } trace_vhost_iotlb_miss(dev, 2); out: return ret; } int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev, struct vhost_virtqueue *vq, unsigned idx) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); VirtioBusState *vbus = VIRTIO_BUS(qbus); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); hwaddr s, l, a; int r; int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); struct vhost_vring_file file = { .index = vhost_vq_index }; struct vhost_vring_state state = { .index = vhost_vq_index }; struct VirtQueue *vvq = virtio_get_queue(vdev, idx); a = virtio_queue_get_desc_addr(vdev, idx); if (a == 0) { /* Queue might not be ready for start */ return 0; } vq->num = state.num = virtio_queue_get_num(vdev, idx); r = dev->vhost_ops->vhost_set_vring_num(dev, &state); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_num failed"); return r; } state.num = virtio_queue_get_last_avail_idx(vdev, idx); r = dev->vhost_ops->vhost_set_vring_base(dev, &state); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_base failed"); return r; } if (vhost_needs_vring_endian(vdev)) { r = vhost_virtqueue_set_vring_endian_legacy(dev, virtio_is_big_endian(vdev), vhost_vq_index); if (r) { return r; } } vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx); vq->desc_phys = a; vq->desc = vhost_memory_map(dev, a, &l, false); if (!vq->desc || l != s) { r = -ENOMEM; goto fail_alloc_desc; } vq->avail_size = s = l = virtio_queue_get_avail_size(vdev, idx); vq->avail_phys = a = virtio_queue_get_avail_addr(vdev, idx); vq->avail = vhost_memory_map(dev, a, &l, false); if (!vq->avail || l != s) { r = -ENOMEM; goto fail_alloc_avail; } vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx); vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx); vq->used = vhost_memory_map(dev, a, &l, true); if (!vq->used || l != s) { r = -ENOMEM; goto fail_alloc_used; } r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled); if (r < 0) { goto fail_alloc; } file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq)); r = dev->vhost_ops->vhost_set_vring_kick(dev, &file); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_kick failed"); goto fail_kick; } /* Clear and discard previous events if any. */ event_notifier_test_and_clear(&vq->masked_notifier); /* Init vring in unmasked state, unless guest_notifier_mask * will do it later. */ if (!vdev->use_guest_notifier_mask) { /* TODO: check and handle errors. */ vhost_virtqueue_mask(dev, vdev, idx, false); } if (k->query_guest_notifiers && k->query_guest_notifiers(qbus->parent) && virtio_queue_vector(vdev, idx) == VIRTIO_NO_VECTOR) { file.fd = -1; r = dev->vhost_ops->vhost_set_vring_call(dev, &file); if (r) { goto fail_vector; } } return 0; fail_vector: fail_kick: fail_alloc: vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx), 0, 0); fail_alloc_used: vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx), 0, 0); fail_alloc_avail: vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx), 0, 0); fail_alloc_desc: return r; } void vhost_virtqueue_stop(struct vhost_dev *dev, struct VirtIODevice *vdev, struct vhost_virtqueue *vq, unsigned idx) { int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); struct vhost_vring_state state = { .index = vhost_vq_index, }; int r; if (virtio_queue_get_desc_addr(vdev, idx) == 0) { /* Don't stop the virtqueue which might have not been started */ return; } r = dev->vhost_ops->vhost_get_vring_base(dev, &state); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r); /* Connection to the backend is broken, so let's sync internal * last avail idx to the device used idx. */ virtio_queue_restore_last_avail_idx(vdev, idx); } else { virtio_queue_set_last_avail_idx(vdev, idx, state.num); } virtio_queue_invalidate_signalled_used(vdev, idx); virtio_queue_update_used_idx(vdev, idx); /* In the cross-endian case, we need to reset the vring endianness to * native as legacy devices expect so by default. */ if (vhost_needs_vring_endian(vdev)) { vhost_virtqueue_set_vring_endian_legacy(dev, !virtio_is_big_endian(vdev), vhost_vq_index); } vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx), 1, virtio_queue_get_used_size(vdev, idx)); vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx), 0, virtio_queue_get_avail_size(vdev, idx)); vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx), 0, virtio_queue_get_desc_size(vdev, idx)); } static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev, int n, uint32_t timeout) { int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n); struct vhost_vring_state state = { .index = vhost_vq_index, .num = timeout, }; int r; if (!dev->vhost_ops->vhost_set_vring_busyloop_timeout) { return -EINVAL; } r = dev->vhost_ops->vhost_set_vring_busyloop_timeout(dev, &state); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_busyloop_timeout failed"); return r; } return 0; } static void vhost_virtqueue_error_notifier(EventNotifier *n) { struct vhost_virtqueue *vq = container_of(n, struct vhost_virtqueue, error_notifier); struct vhost_dev *dev = vq->dev; int index = vq - dev->vqs; if (event_notifier_test_and_clear(n) && dev->vdev) { VHOST_OPS_DEBUG(-EINVAL, "vhost vring error in virtqueue %d", dev->vq_index + index); } } static int vhost_virtqueue_init(struct vhost_dev *dev, struct vhost_virtqueue *vq, int n) { int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n); struct vhost_vring_file file = { .index = vhost_vq_index, }; int r = event_notifier_init(&vq->masked_notifier, 0); if (r < 0) { return r; } file.fd = event_notifier_get_wfd(&vq->masked_notifier); r = dev->vhost_ops->vhost_set_vring_call(dev, &file); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_call failed"); goto fail_call; } vq->dev = dev; if (dev->vhost_ops->vhost_set_vring_err) { r = event_notifier_init(&vq->error_notifier, 0); if (r < 0) { goto fail_call; } file.fd = event_notifier_get_fd(&vq->error_notifier); r = dev->vhost_ops->vhost_set_vring_err(dev, &file); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_vring_err failed"); goto fail_err; } event_notifier_set_handler(&vq->error_notifier, vhost_virtqueue_error_notifier); } return 0; fail_err: event_notifier_cleanup(&vq->error_notifier); fail_call: event_notifier_cleanup(&vq->masked_notifier); return r; } static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq) { event_notifier_cleanup(&vq->masked_notifier); if (vq->dev->vhost_ops->vhost_set_vring_err) { event_notifier_set_handler(&vq->error_notifier, NULL); event_notifier_cleanup(&vq->error_notifier); } } int vhost_dev_init(struct vhost_dev *hdev, void *opaque, VhostBackendType backend_type, uint32_t busyloop_timeout, Error **errp) { unsigned int used, reserved, limit; uint64_t features; int i, r, n_initialized_vqs = 0; hdev->vdev = NULL; hdev->migration_blocker = NULL; r = vhost_set_backend_type(hdev, backend_type); assert(r >= 0); r = hdev->vhost_ops->vhost_backend_init(hdev, opaque, errp); if (r < 0) { goto fail; } r = hdev->vhost_ops->vhost_set_owner(hdev); if (r < 0) { error_setg_errno(errp, -r, "vhost_set_owner failed"); goto fail; } r = hdev->vhost_ops->vhost_get_features(hdev, &features); if (r < 0) { error_setg_errno(errp, -r, "vhost_get_features failed"); goto fail; } limit = hdev->vhost_ops->vhost_backend_memslots_limit(hdev); if (limit < MEMORY_DEVICES_SAFE_MAX_MEMSLOTS && memory_devices_memslot_auto_decision_active()) { error_setg(errp, "some memory device (like virtio-mem)" " decided how many memory slots to use based on the overall" " number of memory slots; this vhost backend would further" " restricts the overall number of memory slots"); error_append_hint(errp, "Try plugging this vhost backend before" " plugging such memory devices.\n"); r = -EINVAL; goto fail; } for (i = 0; i < hdev->nvqs; ++i, ++n_initialized_vqs) { r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i); if (r < 0) { error_setg_errno(errp, -r, "Failed to initialize virtqueue %d", i); goto fail; } } if (busyloop_timeout) { for (i = 0; i < hdev->nvqs; ++i) { r = vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, busyloop_timeout); if (r < 0) { error_setg_errno(errp, -r, "Failed to set busyloop timeout"); goto fail_busyloop; } } } hdev->features = features; hdev->memory_listener = (MemoryListener) { .name = "vhost", .begin = vhost_begin, .commit = vhost_commit, .region_add = vhost_region_addnop, .region_nop = vhost_region_addnop, .log_start = vhost_log_start, .log_stop = vhost_log_stop, .log_sync = vhost_log_sync, .log_global_start = vhost_log_global_start, .log_global_stop = vhost_log_global_stop, .priority = MEMORY_LISTENER_PRIORITY_DEV_BACKEND }; hdev->iommu_listener = (MemoryListener) { .name = "vhost-iommu", .region_add = vhost_iommu_region_add, .region_del = vhost_iommu_region_del, }; if (hdev->migration_blocker == NULL) { if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) { error_setg(&hdev->migration_blocker, "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature."); } else if (vhost_dev_log_is_shared(hdev) && !qemu_memfd_alloc_check()) { error_setg(&hdev->migration_blocker, "Migration disabled: failed to allocate shared memory"); } } if (hdev->migration_blocker != NULL) { r = migrate_add_blocker_normal(&hdev->migration_blocker, errp); if (r < 0) { goto fail_busyloop; } } hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions)); hdev->n_mem_sections = 0; hdev->mem_sections = NULL; hdev->log = NULL; hdev->log_size = 0; hdev->log_enabled = false; hdev->started = false; memory_listener_register(&hdev->memory_listener, &address_space_memory); QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); /* * The listener we registered properly updated the corresponding counter. * So we can trust that these values are accurate. */ if (hdev->vhost_ops->vhost_backend_no_private_memslots && hdev->vhost_ops->vhost_backend_no_private_memslots(hdev)) { used = used_shared_memslots; } else { used = used_memslots; } /* * We assume that all reserved memslots actually require a real memslot * in our vhost backend. This might not be true, for example, if the * memslot would be ROM. If ever relevant, we can optimize for that -- * but we'll need additional information about the reservations. */ reserved = memory_devices_get_reserved_memslots(); if (used + reserved > limit) { error_setg(errp, "vhost backend memory slots limit (%d) is less" " than current number of used (%d) and reserved (%d)" " memory slots for memory devices.", limit, used, reserved); r = -EINVAL; goto fail_busyloop; } return 0; fail_busyloop: if (busyloop_timeout) { while (--i >= 0) { vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0); } } fail: hdev->nvqs = n_initialized_vqs; vhost_dev_cleanup(hdev); return r; } void vhost_dev_cleanup(struct vhost_dev *hdev) { int i; trace_vhost_dev_cleanup(hdev); for (i = 0; i < hdev->nvqs; ++i) { vhost_virtqueue_cleanup(hdev->vqs + i); } if (hdev->mem) { /* those are only safe after successful init */ memory_listener_unregister(&hdev->memory_listener); QLIST_REMOVE(hdev, entry); } migrate_del_blocker(&hdev->migration_blocker); g_free(hdev->mem); g_free(hdev->mem_sections); if (hdev->vhost_ops) { hdev->vhost_ops->vhost_backend_cleanup(hdev); } assert(!hdev->log); memset(hdev, 0, sizeof(struct vhost_dev)); } void vhost_dev_disable_notifiers_nvqs(struct vhost_dev *hdev, VirtIODevice *vdev, unsigned int nvqs) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); int i, r; /* * Batch all the host notifiers in a single transaction to avoid * quadratic time complexity in address_space_update_ioeventfds(). */ memory_region_transaction_begin(); for (i = 0; i < nvqs; ++i) { r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, false); if (r < 0) { error_report("vhost VQ %d notifier cleanup failed: %d", i, -r); } assert(r >= 0); } /* * The transaction expects the ioeventfds to be open when it * commits. Do it now, before the cleanup loop. */ memory_region_transaction_commit(); for (i = 0; i < nvqs; ++i) { virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i); } virtio_device_release_ioeventfd(vdev); } /* Stop processing guest IO notifications in qemu. * Start processing them in vhost in kernel. */ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); int i, r; /* We will pass the notifiers to the kernel, make sure that QEMU * doesn't interfere. */ r = virtio_device_grab_ioeventfd(vdev); if (r < 0) { error_report("binding does not support host notifiers"); return r; } /* * Batch all the host notifiers in a single transaction to avoid * quadratic time complexity in address_space_update_ioeventfds(). */ memory_region_transaction_begin(); for (i = 0; i < hdev->nvqs; ++i) { r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, true); if (r < 0) { error_report("vhost VQ %d notifier binding failed: %d", i, -r); memory_region_transaction_commit(); vhost_dev_disable_notifiers_nvqs(hdev, vdev, i); return r; } } memory_region_transaction_commit(); return 0; } /* Stop processing guest IO notifications in vhost. * Start processing them in qemu. * This might actually run the qemu handlers right away, * so virtio in qemu must be completely setup when this is called. */ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) { vhost_dev_disable_notifiers_nvqs(hdev, vdev, hdev->nvqs); } /* Test and clear event pending status. * Should be called after unmask to avoid losing events. */ bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n) { struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index; assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs); return event_notifier_test_and_clear(&vq->masked_notifier); } /* Mask/unmask events from this vq. */ void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, bool mask) { struct VirtQueue *vvq = virtio_get_queue(vdev, n); int r, index = n - hdev->vq_index; struct vhost_vring_file file; /* should only be called after backend is connected */ assert(hdev->vhost_ops); if (mask) { assert(vdev->use_guest_notifier_mask); file.fd = event_notifier_get_wfd(&hdev->vqs[index].masked_notifier); } else { file.fd = event_notifier_get_wfd(virtio_queue_get_guest_notifier(vvq)); } file.index = hdev->vhost_ops->vhost_get_vq_index(hdev, n); r = hdev->vhost_ops->vhost_set_vring_call(hdev, &file); if (r < 0) { error_report("vhost_set_vring_call failed %d", -r); } } bool vhost_config_pending(struct vhost_dev *hdev) { assert(hdev->vhost_ops); if ((hdev->started == false) || (hdev->vhost_ops->vhost_set_config_call == NULL)) { return false; } EventNotifier *notifier = &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier; return event_notifier_test_and_clear(notifier); } void vhost_config_mask(struct vhost_dev *hdev, VirtIODevice *vdev, bool mask) { int fd; int r; EventNotifier *notifier = &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier; EventNotifier *config_notifier = &vdev->config_notifier; assert(hdev->vhost_ops); if ((hdev->started == false) || (hdev->vhost_ops->vhost_set_config_call == NULL)) { return; } if (mask) { assert(vdev->use_guest_notifier_mask); fd = event_notifier_get_fd(notifier); } else { fd = event_notifier_get_fd(config_notifier); } r = hdev->vhost_ops->vhost_set_config_call(hdev, fd); if (r < 0) { error_report("vhost_set_config_call failed %d", -r); } } static void vhost_stop_config_intr(struct vhost_dev *dev) { int fd = -1; assert(dev->vhost_ops); if (dev->vhost_ops->vhost_set_config_call) { dev->vhost_ops->vhost_set_config_call(dev, fd); } } static void vhost_start_config_intr(struct vhost_dev *dev) { int r; assert(dev->vhost_ops); int fd = event_notifier_get_fd(&dev->vdev->config_notifier); if (dev->vhost_ops->vhost_set_config_call) { r = dev->vhost_ops->vhost_set_config_call(dev, fd); if (!r) { event_notifier_set(&dev->vdev->config_notifier); } } } uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits, uint64_t features) { const int *bit = feature_bits; while (*bit != VHOST_INVALID_FEATURE_BIT) { uint64_t bit_mask = (1ULL << *bit); if (!(hdev->features & bit_mask)) { features &= ~bit_mask; } bit++; } return features; } void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits, uint64_t features) { const int *bit = feature_bits; while (*bit != VHOST_INVALID_FEATURE_BIT) { uint64_t bit_mask = (1ULL << *bit); if (features & bit_mask) { hdev->acked_features |= bit_mask; } bit++; } } int vhost_dev_get_config(struct vhost_dev *hdev, uint8_t *config, uint32_t config_len, Error **errp) { assert(hdev->vhost_ops); if (hdev->vhost_ops->vhost_get_config) { return hdev->vhost_ops->vhost_get_config(hdev, config, config_len, errp); } error_setg(errp, "vhost_get_config not implemented"); return -ENOSYS; } int vhost_dev_set_config(struct vhost_dev *hdev, const uint8_t *data, uint32_t offset, uint32_t size, uint32_t flags) { assert(hdev->vhost_ops); if (hdev->vhost_ops->vhost_set_config) { return hdev->vhost_ops->vhost_set_config(hdev, data, offset, size, flags); } return -ENOSYS; } void vhost_dev_set_config_notifier(struct vhost_dev *hdev, const VhostDevConfigOps *ops) { hdev->config_ops = ops; } void vhost_dev_free_inflight(struct vhost_inflight *inflight) { if (inflight && inflight->addr) { qemu_memfd_free(inflight->addr, inflight->size, inflight->fd); inflight->addr = NULL; inflight->fd = -1; } } int vhost_dev_prepare_inflight(struct vhost_dev *hdev, VirtIODevice *vdev) { int r; if (hdev->vhost_ops->vhost_get_inflight_fd == NULL || hdev->vhost_ops->vhost_set_inflight_fd == NULL) { return 0; } hdev->vdev = vdev; r = vhost_dev_set_features(hdev, hdev->log_enabled); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_dev_prepare_inflight failed"); return r; } return 0; } int vhost_dev_set_inflight(struct vhost_dev *dev, struct vhost_inflight *inflight) { int r; if (dev->vhost_ops->vhost_set_inflight_fd && inflight->addr) { r = dev->vhost_ops->vhost_set_inflight_fd(dev, inflight); if (r) { VHOST_OPS_DEBUG(r, "vhost_set_inflight_fd failed"); return r; } } return 0; } int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size, struct vhost_inflight *inflight) { int r; if (dev->vhost_ops->vhost_get_inflight_fd) { r = dev->vhost_ops->vhost_get_inflight_fd(dev, queue_size, inflight); if (r) { VHOST_OPS_DEBUG(r, "vhost_get_inflight_fd failed"); return r; } } return 0; } static int vhost_dev_set_vring_enable(struct vhost_dev *hdev, int enable) { if (!hdev->vhost_ops->vhost_set_vring_enable) { return 0; } /* * For vhost-user devices, if VHOST_USER_F_PROTOCOL_FEATURES has not * been negotiated, the rings start directly in the enabled state, and * .vhost_set_vring_enable callback will fail since * VHOST_USER_SET_VRING_ENABLE is not supported. */ if (hdev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER && !virtio_has_feature(hdev->backend_features, VHOST_USER_F_PROTOCOL_FEATURES)) { return 0; } return hdev->vhost_ops->vhost_set_vring_enable(hdev, enable); } /* * Host notifiers must be enabled at this point. * * If @vrings is true, this function will enable all vrings before starting the * device. If it is false, the vring initialization is left to be done by the * caller. */ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) { int i, r; /* should only be called after backend is connected */ assert(hdev->vhost_ops); trace_vhost_dev_start(hdev, vdev->name, vrings); vdev->vhost_started = true; hdev->started = true; hdev->vdev = vdev; r = vhost_dev_set_features(hdev, hdev->log_enabled); if (r < 0) { goto fail_features; } if (vhost_dev_has_iommu(hdev)) { memory_listener_register(&hdev->iommu_listener, vdev->dma_as); } r = hdev->vhost_ops->vhost_set_mem_table(hdev, hdev->mem); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed"); goto fail_mem; } for (i = 0; i < hdev->nvqs; ++i) { r = vhost_virtqueue_start(hdev, vdev, hdev->vqs + i, hdev->vq_index + i); if (r < 0) { goto fail_vq; } } r = event_notifier_init( &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier, 0); if (r < 0) { VHOST_OPS_DEBUG(r, "event_notifier_init failed"); goto fail_vq; } event_notifier_test_and_clear( &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier); if (!vdev->use_guest_notifier_mask) { vhost_config_mask(hdev, vdev, true); } if (hdev->log_enabled) { uint64_t log_base; hdev->log_size = vhost_get_log_size(hdev); hdev->log = vhost_log_get(hdev->vhost_ops->backend_type, hdev->log_size, vhost_dev_log_is_shared(hdev)); log_base = (uintptr_t)hdev->log->log; r = hdev->vhost_ops->vhost_set_log_base(hdev, hdev->log_size ? log_base : 0, hdev->log); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost_set_log_base failed"); goto fail_log; } vhost_dev_elect_mem_logger(hdev, true); } if (vrings) { r = vhost_dev_set_vring_enable(hdev, true); if (r) { goto fail_log; } } if (hdev->vhost_ops->vhost_dev_start) { r = hdev->vhost_ops->vhost_dev_start(hdev, true); if (r) { goto fail_start; } } if (vhost_dev_has_iommu(hdev) && hdev->vhost_ops->vhost_set_iotlb_callback) { hdev->vhost_ops->vhost_set_iotlb_callback(hdev, true); /* Update used ring information for IOTLB to work correctly, * vhost-kernel code requires for this.*/ for (i = 0; i < hdev->nvqs; ++i) { struct vhost_virtqueue *vq = hdev->vqs + i; r = vhost_device_iotlb_miss(hdev, vq->used_phys, true); if (r) { goto fail_iotlb; } } } vhost_start_config_intr(hdev); return 0; fail_iotlb: if (vhost_dev_has_iommu(hdev) && hdev->vhost_ops->vhost_set_iotlb_callback) { hdev->vhost_ops->vhost_set_iotlb_callback(hdev, false); } if (hdev->vhost_ops->vhost_dev_start) { hdev->vhost_ops->vhost_dev_start(hdev, false); } fail_start: if (vrings) { vhost_dev_set_vring_enable(hdev, false); } fail_log: vhost_log_put(hdev, false); fail_vq: while (--i >= 0) { vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, hdev->vq_index + i); } fail_mem: if (vhost_dev_has_iommu(hdev)) { memory_listener_unregister(&hdev->iommu_listener); } fail_features: vdev->vhost_started = false; hdev->started = false; return r; } /* Host notifiers must be enabled at this point. */ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) { int i; /* should only be called after backend is connected */ assert(hdev->vhost_ops); event_notifier_test_and_clear( &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier); event_notifier_test_and_clear(&vdev->config_notifier); event_notifier_cleanup( &hdev->vqs[VHOST_QUEUE_NUM_CONFIG_INR].masked_config_notifier); trace_vhost_dev_stop(hdev, vdev->name, vrings); if (hdev->vhost_ops->vhost_dev_start) { hdev->vhost_ops->vhost_dev_start(hdev, false); } if (vrings) { vhost_dev_set_vring_enable(hdev, false); } for (i = 0; i < hdev->nvqs; ++i) { vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, hdev->vq_index + i); } if (hdev->vhost_ops->vhost_reset_status) { hdev->vhost_ops->vhost_reset_status(hdev); } if (vhost_dev_has_iommu(hdev)) { if (hdev->vhost_ops->vhost_set_iotlb_callback) { hdev->vhost_ops->vhost_set_iotlb_callback(hdev, false); } memory_listener_unregister(&hdev->iommu_listener); } vhost_stop_config_intr(hdev); vhost_log_put(hdev, true); hdev->started = false; vdev->vhost_started = false; hdev->vdev = NULL; } int vhost_net_set_backend(struct vhost_dev *hdev, struct vhost_vring_file *file) { if (hdev->vhost_ops->vhost_net_set_backend) { return hdev->vhost_ops->vhost_net_set_backend(hdev, file); } return -ENOSYS; } int vhost_reset_device(struct vhost_dev *hdev) { if (hdev->vhost_ops->vhost_reset_device) { return hdev->vhost_ops->vhost_reset_device(hdev); } return -ENOSYS; } bool vhost_supports_device_state(struct vhost_dev *dev) { if (dev->vhost_ops->vhost_supports_device_state) { return dev->vhost_ops->vhost_supports_device_state(dev); } return false; } int vhost_set_device_state_fd(struct vhost_dev *dev, VhostDeviceStateDirection direction, VhostDeviceStatePhase phase, int fd, int *reply_fd, Error **errp) { if (dev->vhost_ops->vhost_set_device_state_fd) { return dev->vhost_ops->vhost_set_device_state_fd(dev, direction, phase, fd, reply_fd, errp); } error_setg(errp, "vhost transport does not support migration state transfer"); return -ENOSYS; } int vhost_check_device_state(struct vhost_dev *dev, Error **errp) { if (dev->vhost_ops->vhost_check_device_state) { return dev->vhost_ops->vhost_check_device_state(dev, errp); } error_setg(errp, "vhost transport does not support migration state transfer"); return -ENOSYS; } int vhost_save_backend_state(struct vhost_dev *dev, QEMUFile *f, Error **errp) { ERRP_GUARD(); /* Maximum chunk size in which to transfer the state */ const size_t chunk_size = 1 * 1024 * 1024; g_autofree void *transfer_buf = NULL; g_autoptr(GError) g_err = NULL; int pipe_fds[2], read_fd = -1, write_fd = -1, reply_fd = -1; int ret; /* [0] for reading (our end), [1] for writing (back-end's end) */ if (!g_unix_open_pipe(pipe_fds, FD_CLOEXEC, &g_err)) { error_setg(errp, "Failed to set up state transfer pipe: %s", g_err->message); ret = -EINVAL; goto fail; } read_fd = pipe_fds[0]; write_fd = pipe_fds[1]; /* * VHOST_TRANSFER_STATE_PHASE_STOPPED means the device must be stopped. * Ideally, it is suspended, but SUSPEND/RESUME currently do not exist for * vhost-user, so just check that it is stopped at all. */ assert(!dev->started); /* Transfer ownership of write_fd to the back-end */ ret = vhost_set_device_state_fd(dev, VHOST_TRANSFER_STATE_DIRECTION_SAVE, VHOST_TRANSFER_STATE_PHASE_STOPPED, write_fd, &reply_fd, errp); if (ret < 0) { error_prepend(errp, "Failed to initiate state transfer: "); goto fail; } /* If the back-end wishes to use a different pipe, switch over */ if (reply_fd >= 0) { close(read_fd); read_fd = reply_fd; } transfer_buf = g_malloc(chunk_size); while (true) { ssize_t read_ret; read_ret = RETRY_ON_EINTR(read(read_fd, transfer_buf, chunk_size)); if (read_ret < 0) { ret = -errno; error_setg_errno(errp, -ret, "Failed to receive state"); goto fail; } assert(read_ret <= chunk_size); qemu_put_be32(f, read_ret); if (read_ret == 0) { /* EOF */ break; } qemu_put_buffer(f, transfer_buf, read_ret); } /* * Back-end will not really care, but be clean and close our end of the pipe * before inquiring the back-end about whether transfer was successful */ close(read_fd); read_fd = -1; /* Also, verify that the device is still stopped */ assert(!dev->started); ret = vhost_check_device_state(dev, errp); if (ret < 0) { goto fail; } ret = 0; fail: if (read_fd >= 0) { close(read_fd); } return ret; } int vhost_load_backend_state(struct vhost_dev *dev, QEMUFile *f, Error **errp) { ERRP_GUARD(); size_t transfer_buf_size = 0; g_autofree void *transfer_buf = NULL; g_autoptr(GError) g_err = NULL; int pipe_fds[2], read_fd = -1, write_fd = -1, reply_fd = -1; int ret; /* [0] for reading (back-end's end), [1] for writing (our end) */ if (!g_unix_open_pipe(pipe_fds, FD_CLOEXEC, &g_err)) { error_setg(errp, "Failed to set up state transfer pipe: %s", g_err->message); ret = -EINVAL; goto fail; } read_fd = pipe_fds[0]; write_fd = pipe_fds[1]; /* * VHOST_TRANSFER_STATE_PHASE_STOPPED means the device must be stopped. * Ideally, it is suspended, but SUSPEND/RESUME currently do not exist for * vhost-user, so just check that it is stopped at all. */ assert(!dev->started); /* Transfer ownership of read_fd to the back-end */ ret = vhost_set_device_state_fd(dev, VHOST_TRANSFER_STATE_DIRECTION_LOAD, VHOST_TRANSFER_STATE_PHASE_STOPPED, read_fd, &reply_fd, errp); if (ret < 0) { error_prepend(errp, "Failed to initiate state transfer: "); goto fail; } /* If the back-end wishes to use a different pipe, switch over */ if (reply_fd >= 0) { close(write_fd); write_fd = reply_fd; } while (true) { size_t this_chunk_size = qemu_get_be32(f); ssize_t write_ret; const uint8_t *transfer_pointer; if (this_chunk_size == 0) { /* End of state */ break; } if (transfer_buf_size < this_chunk_size) { transfer_buf = g_realloc(transfer_buf, this_chunk_size); transfer_buf_size = this_chunk_size; } if (qemu_get_buffer(f, transfer_buf, this_chunk_size) < this_chunk_size) { error_setg(errp, "Failed to read state"); ret = -EINVAL; goto fail; } transfer_pointer = transfer_buf; while (this_chunk_size > 0) { write_ret = RETRY_ON_EINTR( write(write_fd, transfer_pointer, this_chunk_size) ); if (write_ret < 0) { ret = -errno; error_setg_errno(errp, -ret, "Failed to send state"); goto fail; } else if (write_ret == 0) { error_setg(errp, "Failed to send state: Connection is closed"); ret = -ECONNRESET; goto fail; } assert(write_ret <= this_chunk_size); this_chunk_size -= write_ret; transfer_pointer += write_ret; } } /* * Close our end, thus ending transfer, before inquiring the back-end about * whether transfer was successful */ close(write_fd); write_fd = -1; /* Also, verify that the device is still stopped */ assert(!dev->started); ret = vhost_check_device_state(dev, errp); if (ret < 0) { goto fail; } ret = 0; fail: if (write_fd >= 0) { close(write_fd); } return ret; }