/* * 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 "hw/virtio/vhost.h" #include "hw/hw.h" #include "qemu/atomic.h" #include "qemu/range.h" #include "qemu/error-report.h" #include "qemu/memfd.h" #include #include "exec/address-spaces.h" #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" #include "migration/migration.h" static struct vhost_log *vhost_log; static struct vhost_log *vhost_log_shm; static unsigned int used_memslots; static QLIST_HEAD(, vhost_dev) vhost_devices = QLIST_HEAD_INITIALIZER(vhost_devices); bool vhost_has_free_slot(void) { unsigned int slots_limit = ~0U; struct vhost_dev *hdev; QLIST_FOREACH(hdev, &vhost_devices, entry) { unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev); slots_limit = MIN(slots_limit, r); } return slots_limit > used_memslots; } 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 *log = dev->log->log; uint64_t start = MAX(mfirst, rfirst); uint64_t end = MIN(mlast, rlast); vhost_log_chunk_t *from = log + start / VHOST_LOG_CHUNK; vhost_log_chunk_t *to = log + end / VHOST_LOG_CHUNK + 1; uint64_t addr = (start / VHOST_LOG_CHUNK) * 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 = atomic_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; } } 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); 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; 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); } } /* Assign/unassign. Keep an unsorted array of non-overlapping * memory regions in dev->mem. */ static void vhost_dev_unassign_memory(struct vhost_dev *dev, uint64_t start_addr, uint64_t size) { int from, to, n = dev->mem->nregions; /* Track overlapping/split regions for sanity checking. */ int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0; for (from = 0, to = 0; from < n; ++from, ++to) { struct vhost_memory_region *reg = dev->mem->regions + to; uint64_t reglast; uint64_t memlast; uint64_t change; /* clone old region */ if (to != from) { memcpy(reg, dev->mem->regions + from, sizeof *reg); } /* No overlap is simple */ if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size, start_addr, size)) { continue; } /* Split only happens if supplied region * is in the middle of an existing one. Thus it can not * overlap with any other existing region. */ assert(!split); reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); memlast = range_get_last(start_addr, size); /* Remove whole region */ if (start_addr <= reg->guest_phys_addr && memlast >= reglast) { --dev->mem->nregions; --to; ++overlap_middle; continue; } /* Shrink region */ if (memlast >= reglast) { reg->memory_size = start_addr - reg->guest_phys_addr; assert(reg->memory_size); assert(!overlap_end); ++overlap_end; continue; } /* Shift region */ if (start_addr <= reg->guest_phys_addr) { change = memlast + 1 - reg->guest_phys_addr; reg->memory_size -= change; reg->guest_phys_addr += change; reg->userspace_addr += change; assert(reg->memory_size); assert(!overlap_start); ++overlap_start; continue; } /* This only happens if supplied region * is in the middle of an existing one. Thus it can not * overlap with any other existing region. */ assert(!overlap_start); assert(!overlap_end); assert(!overlap_middle); /* Split region: shrink first part, shift second part. */ memcpy(dev->mem->regions + n, reg, sizeof *reg); reg->memory_size = start_addr - reg->guest_phys_addr; assert(reg->memory_size); change = memlast + 1 - reg->guest_phys_addr; reg = dev->mem->regions + n; reg->memory_size -= change; assert(reg->memory_size); reg->guest_phys_addr += change; reg->userspace_addr += change; /* Never add more than 1 region */ assert(dev->mem->nregions == n); ++dev->mem->nregions; ++split; } } /* Called after unassign, so no regions overlap the given range. */ static void vhost_dev_assign_memory(struct vhost_dev *dev, uint64_t start_addr, uint64_t size, uint64_t uaddr) { int from, to; struct vhost_memory_region *merged = NULL; for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) { struct vhost_memory_region *reg = dev->mem->regions + to; uint64_t prlast, urlast; uint64_t pmlast, umlast; uint64_t s, e, u; /* clone old region */ if (to != from) { memcpy(reg, dev->mem->regions + from, sizeof *reg); } prlast = range_get_last(reg->guest_phys_addr, reg->memory_size); pmlast = range_get_last(start_addr, size); urlast = range_get_last(reg->userspace_addr, reg->memory_size); umlast = range_get_last(uaddr, size); /* check for overlapping regions: should never happen. */ assert(prlast < start_addr || pmlast < reg->guest_phys_addr); /* Not an adjacent or overlapping region - do not merge. */ if ((prlast + 1 != start_addr || urlast + 1 != uaddr) && (pmlast + 1 != reg->guest_phys_addr || umlast + 1 != reg->userspace_addr)) { continue; } if (merged) { --to; assert(to >= 0); } else { merged = reg; } u = MIN(uaddr, reg->userspace_addr); s = MIN(start_addr, reg->guest_phys_addr); e = MAX(pmlast, prlast); uaddr = merged->userspace_addr = u; start_addr = merged->guest_phys_addr = s; size = merged->memory_size = e - s + 1; assert(merged->memory_size); } if (!merged) { struct vhost_memory_region *reg = dev->mem->regions + to; memset(reg, 0, sizeof *reg); reg->memory_size = size; assert(reg->memory_size); reg->guest_phys_addr = start_addr; reg->userspace_addr = uaddr; ++to; } assert(to <= dev->mem->nregions + 1); dev->mem->nregions = to; } 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); } for (i = 0; i < dev->nvqs; ++i) { struct vhost_virtqueue *vq = dev->vqs + i; uint64_t last = vq->used_phys + vq->used_size - 1; log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); } return log_size; } static struct vhost_log *vhost_log_alloc(uint64_t size, bool share) { 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); 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(uint64_t size, bool share) { struct vhost_log *log = share ? vhost_log_shm : vhost_log; if (!log || log->size != size) { log = vhost_log_alloc(size, share); if (share) { vhost_log_shm = log; } else { vhost_log = log; } } else { ++log->refcnt; } return log; } static void vhost_log_put(struct vhost_dev *dev, bool sync) { struct vhost_log *log = dev->log; if (!log) { 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 == log) { g_free(log->log); vhost_log = NULL; } else if (vhost_log_shm == log) { qemu_memfd_free(log->log, log->size * sizeof(*(log->log)), log->fd); vhost_log_shm = NULL; } g_free(log); } } 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(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); assert(r >= 0); vhost_log_put(dev, true); dev->log = log; dev->log_size = size; } static int vhost_verify_ring_mappings(struct vhost_dev *dev, uint64_t start_addr, uint64_t size) { int i; int r = 0; for (i = 0; !r && i < dev->nvqs; ++i) { struct vhost_virtqueue *vq = dev->vqs + i; hwaddr l; void *p; if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { continue; } l = vq->ring_size; p = cpu_physical_memory_map(vq->ring_phys, &l, 1); if (!p || l != vq->ring_size) { fprintf(stderr, "Unable to map ring buffer for ring %d\n", i); r = -ENOMEM; } if (p != vq->ring) { fprintf(stderr, "Ring buffer relocated for ring %d\n", i); r = -EBUSY; } cpu_physical_memory_unmap(p, l, 0, 0); } return r; } static struct vhost_memory_region *vhost_dev_find_reg(struct vhost_dev *dev, uint64_t start_addr, uint64_t size) { int i, n = dev->mem->nregions; for (i = 0; i < n; ++i) { struct vhost_memory_region *reg = dev->mem->regions + i; if (ranges_overlap(reg->guest_phys_addr, reg->memory_size, start_addr, size)) { return reg; } } return NULL; } static bool vhost_dev_cmp_memory(struct vhost_dev *dev, uint64_t start_addr, uint64_t size, uint64_t uaddr) { struct vhost_memory_region *reg = vhost_dev_find_reg(dev, start_addr, size); uint64_t reglast; uint64_t memlast; if (!reg) { return true; } reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); memlast = range_get_last(start_addr, size); /* Need to extend region? */ if (start_addr < reg->guest_phys_addr || memlast > reglast) { return true; } /* userspace_addr changed? */ return uaddr != reg->userspace_addr + start_addr - reg->guest_phys_addr; } static void vhost_set_memory(MemoryListener *listener, MemoryRegionSection *section, bool add) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); hwaddr start_addr = section->offset_within_address_space; ram_addr_t size = int128_get64(section->size); bool log_dirty = memory_region_get_dirty_log_mask(section->mr) & ~(1 << DIRTY_MEMORY_MIGRATION); int s = offsetof(struct vhost_memory, regions) + (dev->mem->nregions + 1) * sizeof dev->mem->regions[0]; void *ram; dev->mem = g_realloc(dev->mem, s); if (log_dirty) { add = false; } assert(size); /* Optimize no-change case. At least cirrus_vga does this a lot at this time. */ ram = memory_region_get_ram_ptr(section->mr) + section->offset_within_region; if (add) { if (!vhost_dev_cmp_memory(dev, start_addr, size, (uintptr_t)ram)) { /* Region exists with same address. Nothing to do. */ return; } } else { if (!vhost_dev_find_reg(dev, start_addr, size)) { /* Removing region that we don't access. Nothing to do. */ return; } } vhost_dev_unassign_memory(dev, start_addr, size); if (add) { /* Add given mapping, merging adjacent regions if any */ vhost_dev_assign_memory(dev, start_addr, size, (uintptr_t)ram); } else { /* Remove old mapping for this memory, if any. */ vhost_dev_unassign_memory(dev, start_addr, size); } dev->mem_changed_start_addr = MIN(dev->mem_changed_start_addr, start_addr); dev->mem_changed_end_addr = MAX(dev->mem_changed_end_addr, start_addr + size - 1); dev->memory_changed = true; used_memslots = dev->mem->nregions; } static bool vhost_section(MemoryRegionSection *section) { return memory_region_is_ram(section->mr); } static void vhost_begin(MemoryListener *listener) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); dev->mem_changed_end_addr = 0; dev->mem_changed_start_addr = -1; } static void vhost_commit(MemoryListener *listener) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); hwaddr start_addr = 0; ram_addr_t size = 0; uint64_t log_size; int r; if (!dev->memory_changed) { return; } if (!dev->started) { return; } if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) { return; } if (dev->started) { start_addr = dev->mem_changed_start_addr; size = dev->mem_changed_end_addr - dev->mem_changed_start_addr + 1; r = vhost_verify_ring_mappings(dev, start_addr, size); assert(r >= 0); } if (!dev->log_enabled) { r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); assert(r >= 0); dev->memory_changed = false; return; } 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); assert(r >= 0); /* 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); } dev->memory_changed = false; } static void vhost_region_add(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); if (!vhost_section(section)) { return; } ++dev->n_mem_sections; dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections, dev->n_mem_sections); dev->mem_sections[dev->n_mem_sections - 1] = *section; memory_region_ref(section->mr); vhost_set_memory(listener, section, true); } static void vhost_region_del(MemoryListener *listener, MemoryRegionSection *section) { struct vhost_dev *dev = container_of(listener, struct vhost_dev, memory_listener); int i; if (!vhost_section(section)) { return; } vhost_set_memory(listener, section, false); memory_region_unref(section->mr); for (i = 0; i < dev->n_mem_sections; ++i) { if (dev->mem_sections[i].offset_within_address_space == section->offset_within_address_space) { --dev->n_mem_sections; memmove(&dev->mem_sections[i], &dev->mem_sections[i+1], (dev->n_mem_sections - i) * sizeof(*dev->mem_sections)); break; } } } static void vhost_region_nop(MemoryListener *listener, MemoryRegionSection *section) { } static int vhost_virtqueue_set_addr(struct vhost_dev *dev, struct vhost_virtqueue *vq, unsigned idx, bool enable_log) { struct vhost_vring_addr addr = { .index = idx, .desc_user_addr = (uint64_t)(unsigned long)vq->desc, .avail_user_addr = (uint64_t)(unsigned long)vq->avail, .used_user_addr = (uint64_t)(unsigned long)vq->used, .log_guest_addr = vq->used_phys, .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0, }; int r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr); if (r < 0) { return -errno; } return 0; } 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; } r = dev->vhost_ops->vhost_set_features(dev, features); return r < 0 ? -errno : 0; } static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) { int r, t, i, idx; 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); r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, enable_log); if (r < 0) { goto err_vq; } } return 0; err_vq: for (; i >= 0; --i) { idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); t = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, dev->log_enabled); assert(t >= 0); } t = vhost_dev_set_features(dev, dev->log_enabled); assert(t >= 0); err_features: return r; } static int vhost_migration_log(MemoryListener *listener, int 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; } if (!enable) { r = vhost_dev_set_log(dev, false); if (r < 0) { return r; } vhost_log_put(dev, false); dev->log = NULL; dev->log_size = 0; } else { vhost_dev_log_resize(dev, vhost_get_log_size(dev)); r = vhost_dev_set_log(dev, true); if (r < 0) { return r; } } dev->log_enabled = enable; return 0; } static void vhost_log_global_start(MemoryListener *listener) { int r; r = vhost_migration_log(listener, true); if (r < 0) { abort(); } } 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 */ } static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev, bool is_big_endian, int vhost_vq_index) { struct vhost_vring_state s = { .index = vhost_vq_index, .num = is_big_endian }; if (!dev->vhost_ops->vhost_set_vring_endian(dev, &s)) { return 0; } if (errno == ENOTTY) { error_report("vhost does not support cross-endian"); return -ENOSYS; } return -errno; } static int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev, struct vhost_virtqueue *vq, unsigned idx) { 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); vq->num = state.num = virtio_queue_get_num(vdev, idx); r = dev->vhost_ops->vhost_set_vring_num(dev, &state); if (r) { return -errno; } state.num = virtio_queue_get_last_avail_idx(vdev, idx); r = dev->vhost_ops->vhost_set_vring_base(dev, &state); if (r) { return -errno; } if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1) && virtio_legacy_is_cross_endian(vdev)) { r = vhost_virtqueue_set_vring_endian_legacy(dev, virtio_is_big_endian(vdev), vhost_vq_index); if (r) { return -errno; } } s = l = virtio_queue_get_desc_size(vdev, idx); a = virtio_queue_get_desc_addr(vdev, idx); vq->desc = cpu_physical_memory_map(a, &l, 0); if (!vq->desc || l != s) { r = -ENOMEM; goto fail_alloc_desc; } s = l = virtio_queue_get_avail_size(vdev, idx); a = virtio_queue_get_avail_addr(vdev, idx); vq->avail = cpu_physical_memory_map(a, &l, 0); 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 = cpu_physical_memory_map(a, &l, 1); if (!vq->used || l != s) { r = -ENOMEM; goto fail_alloc_used; } vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx); vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx); vq->ring = cpu_physical_memory_map(a, &l, 1); if (!vq->ring || l != s) { r = -ENOMEM; goto fail_alloc_ring; } r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled); if (r < 0) { r = -errno; 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) { r = -errno; goto fail_kick; } /* Clear and discard previous events if any. */ event_notifier_test_and_clear(&vq->masked_notifier); return 0; fail_kick: fail_alloc: cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 0, 0); fail_alloc_ring: cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 0, 0); fail_alloc_used: cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 0, 0); fail_alloc_avail: cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 0, 0); fail_alloc_desc: return r; } static 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; r = dev->vhost_ops->vhost_get_vring_base(dev, &state); if (r < 0) { fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r); fflush(stderr); } virtio_queue_set_last_avail_idx(vdev, idx, state.num); virtio_queue_invalidate_signalled_used(vdev, idx); /* In the cross-endian case, we need to reset the vring endianness to * native as legacy devices expect so by default. */ if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1) && virtio_legacy_is_cross_endian(vdev)) { r = vhost_virtqueue_set_vring_endian_legacy(dev, !virtio_is_big_endian(vdev), vhost_vq_index); if (r < 0) { error_report("failed to reset vring endianness"); } } assert (r >= 0); cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 0, virtio_queue_get_ring_size(vdev, idx)); cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 1, virtio_queue_get_used_size(vdev, idx)); cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 0, virtio_queue_get_avail_size(vdev, idx)); cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 0, virtio_queue_get_desc_size(vdev, idx)); } static void vhost_eventfd_add(MemoryListener *listener, MemoryRegionSection *section, bool match_data, uint64_t data, EventNotifier *e) { } static void vhost_eventfd_del(MemoryListener *listener, MemoryRegionSection *section, bool match_data, uint64_t data, EventNotifier *e) { } 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_fd(&vq->masked_notifier); r = dev->vhost_ops->vhost_set_vring_call(dev, &file); if (r) { r = -errno; goto fail_call; } return 0; 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); } int vhost_dev_init(struct vhost_dev *hdev, void *opaque, VhostBackendType backend_type) { uint64_t features; int i, r; hdev->migration_blocker = NULL; if (vhost_set_backend_type(hdev, backend_type) < 0) { close((uintptr_t)opaque); return -1; } if (hdev->vhost_ops->vhost_backend_init(hdev, opaque) < 0) { close((uintptr_t)opaque); return -errno; } if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { fprintf(stderr, "vhost backend memory slots limit is less" " than current number of present memory slots\n"); close((uintptr_t)opaque); return -1; } QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); r = hdev->vhost_ops->vhost_set_owner(hdev); if (r < 0) { goto fail; } r = hdev->vhost_ops->vhost_get_features(hdev, &features); if (r < 0) { goto fail; } for (i = 0; i < hdev->nvqs; ++i) { r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i); if (r < 0) { goto fail_vq; } } hdev->features = features; hdev->memory_listener = (MemoryListener) { .begin = vhost_begin, .commit = vhost_commit, .region_add = vhost_region_add, .region_del = vhost_region_del, .region_nop = vhost_region_nop, .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, .eventfd_add = vhost_eventfd_add, .eventfd_del = vhost_eventfd_del, .priority = 10 }; 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 (!qemu_memfd_check()) { error_setg(&hdev->migration_blocker, "Migration disabled: failed to allocate shared memory"); } } if (hdev->migration_blocker != NULL) { migrate_add_blocker(hdev->migration_blocker); } 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; hdev->memory_changed = false; memory_listener_register(&hdev->memory_listener, &address_space_memory); return 0; fail_vq: while (--i >= 0) { vhost_virtqueue_cleanup(hdev->vqs + i); } fail: r = -errno; hdev->vhost_ops->vhost_backend_cleanup(hdev); QLIST_REMOVE(hdev, entry); return r; } void vhost_dev_cleanup(struct vhost_dev *hdev) { int i; for (i = 0; i < hdev->nvqs; ++i) { vhost_virtqueue_cleanup(hdev->vqs + i); } memory_listener_unregister(&hdev->memory_listener); if (hdev->migration_blocker) { migrate_del_blocker(hdev->migration_blocker); error_free(hdev->migration_blocker); } g_free(hdev->mem); g_free(hdev->mem_sections); hdev->vhost_ops->vhost_backend_cleanup(hdev); QLIST_REMOVE(hdev, entry); } /* 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))); VirtioBusState *vbus = VIRTIO_BUS(qbus); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); int i, r, e; if (!k->set_host_notifier) { fprintf(stderr, "binding does not support host notifiers\n"); r = -ENOSYS; goto fail; } for (i = 0; i < hdev->nvqs; ++i) { r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, true); if (r < 0) { fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r); goto fail_vq; } } return 0; fail_vq: while (--i >= 0) { e = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false); if (e < 0) { fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r); fflush(stderr); } assert (e >= 0); } fail: return r; } /* 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) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); VirtioBusState *vbus = VIRTIO_BUS(qbus); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); int i, r; for (i = 0; i < hdev->nvqs; ++i) { r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false); if (r < 0) { fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r); fflush(stderr); } assert (r >= 0); } } /* 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; if (mask) { file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier); } else { file.fd = event_notifier_get_fd(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); assert(r >= 0); } 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++; } } /* Host notifiers must be enabled at this point. */ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) { int i, r; hdev->started = true; r = vhost_dev_set_features(hdev, hdev->log_enabled); if (r < 0) { goto fail_features; } r = hdev->vhost_ops->vhost_set_mem_table(hdev, hdev->mem); if (r < 0) { r = -errno; 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; } } if (hdev->log_enabled) { uint64_t log_base; hdev->log_size = vhost_get_log_size(hdev); hdev->log = vhost_log_get(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) { r = -errno; goto fail_log; } } if (hdev->vhost_ops->vhost_set_vring_enable) { /* only enable first vq pair by default */ hdev->vhost_ops->vhost_set_vring_enable(hdev, hdev->vq_index == 0); } return 0; fail_log: vhost_log_put(hdev, false); fail_vq: while (--i >= 0) { vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, hdev->vq_index + i); } i = hdev->nvqs; fail_mem: fail_features: hdev->started = false; return r; } /* Host notifiers must be enabled at this point. */ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) { int i; for (i = 0; i < hdev->nvqs; ++i) { vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, hdev->vq_index + i); } if (hdev->vhost_ops->vhost_set_vring_enable) { hdev->vhost_ops->vhost_set_vring_enable(hdev, 0); } vhost_log_put(hdev, true); hdev->started = false; hdev->log = NULL; hdev->log_size = 0; }