Rework vhost memory region updates

index e4290ce93d..610bfe6945 100644
@@ -621,6 +621,8 @@ static void vhost_begin(MemoryListener *listener)
                                          memory_listener);
     dev->mem_changed_end_addr = 0;
     dev->mem_changed_start_addr = -1;
+    dev->tmp_sections = NULL;
+    dev->n_tmp_sections = 0;
 }
 
 static void vhost_commit(MemoryListener *listener)

@@ -629,17 +631,25 @@ static void vhost_commit(MemoryListener *listener)
                                          memory_listener);
     hwaddr start_addr = 0;
     ram_addr_t size = 0;
+    MemoryRegionSection *old_sections;
+    int n_old_sections;
+
     uint64_t log_size;
     int r;
 
+    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->memory_changed) {
-        return;
+        goto out;
     }
     if (!dev->started) {
-        return;
+        goto out;
     }
     if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) {
-        return;
+        goto out;
     }
 
     if (dev->started) {

@@ -656,7 +666,7 @@ static void vhost_commit(MemoryListener *listener)
             VHOST_OPS_DEBUG("vhost_set_mem_table failed");
         }
         dev->memory_changed = false;
-        return;
+        goto out;
     }
     log_size = vhost_get_log_size(dev);
     /* We allocate an extra 4K bytes to log,

@@ -675,6 +685,27 @@ static void vhost_commit(MemoryListener *listener)
         vhost_dev_log_resize(dev, log_size);
     }
     dev->memory_changed = false;
+
+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;
+}
+
+static void vhost_add_section(struct vhost_dev *dev,
+                              MemoryRegionSection *section)
+{
+    ++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;
+    memory_region_ref(section->mr);
 }
 
 static void vhost_region_add(MemoryListener *listener,

@@ -687,36 +718,31 @@ static void vhost_region_add(MemoryListener *listener,
         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_add_section(dev, section);
     vhost_set_memory(listener, section, true);
 }
 
-static void vhost_region_del(MemoryListener *listener,
+static void vhost_region_nop(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;
-        }
+    vhost_add_section(dev, section);
+}
+
+static void vhost_region_del(MemoryListener *listener,
+                             MemoryRegionSection *section)
+{
+    if (!vhost_section(section)) {
+        return;
     }
+
+    vhost_set_memory(listener, section, false);
 }
 
 static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)

@@ -783,11 +809,6 @@ static void vhost_iommu_region_del(MemoryListener *listener,
     }
 }
 
-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)

index 467dc7794b..21f3022499 100644
@@ -54,6 +54,8 @@ struct vhost_dev {
     struct vhost_memory *mem;
     int n_mem_sections;
     MemoryRegionSection *mem_sections;
+    int n_tmp_sections;
+    MemoryRegionSection *tmp_sections;
     struct vhost_virtqueue *vqs;
     int nvqs;
     /* the first virtqueue which would be used by this vhost dev */

index 610bfe6945..999ce48259 100644
@@ -449,35 +449,37 @@ static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer,
     }
 }
 
-static int vhost_verify_ring_part_mapping(struct vhost_dev *dev,
-                                          void *part,
-                                          uint64_t part_addr,
-                                          uint64_t part_size,
-                                          uint64_t start_addr,
-                                          uint64_t size)
+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)
 {
-    hwaddr l;
-    void *p;
-    int r = 0;
+    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 (!ranges_overlap(start_addr, size, part_addr, part_size)) {
+    if (ring_last < reg_gpa || ring_gpa > reg_last) {
         return 0;
     }
-    l = part_size;
-    p = vhost_memory_map(dev, part_addr, &l, 1);
-    if (!p || l != part_size) {
-        r = -ENOMEM;
+    /* check that whole ring's is mapped */
+    if (ring_last > reg_last) {
+        return -ENOMEM;
     }
-    if (p != part) {
-        r = -EBUSY;
+    /* 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;
     }
-    vhost_memory_unmap(dev, p, l, 0, 0);
-    return r;
+
+    return 0;
 }
 
 static int vhost_verify_ring_mappings(struct vhost_dev *dev,
-                                      uint64_t start_addr,
-                                      uint64_t size)
+                                      void *reg_hva,
+                                      uint64_t reg_gpa,
+                                      uint64_t reg_size)
 {
     int i, j;
     int r = 0;

@@ -491,22 +493,25 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
         struct vhost_virtqueue *vq = dev->vqs + i;
 
         j = 0;
-        r = vhost_verify_ring_part_mapping(dev, vq->desc, vq->desc_phys,
-                                           vq->desc_size, start_addr, size);
+        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(dev, vq->avail, vq->avail_phys,
-                                           vq->avail_size, start_addr, size);
+        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(dev, vq->used, vq->used_phys,
-                                           vq->used_size, start_addr, size);
+        r = vhost_verify_ring_part_mapping(
+                vq->desc, vq->desc_phys, vq->desc_size,
+                reg_hva, reg_gpa, reg_size);
         if (r) {
             break;
         }

@@ -629,13 +634,11 @@ 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;
     MemoryRegionSection *old_sections;
     int n_old_sections;
-
     uint64_t log_size;
     int r;
+    int i;
 
     old_sections = dev->mem_sections;
     n_old_sections = dev->n_mem_sections;

@@ -652,12 +655,14 @@ static void vhost_commit(MemoryListener *listener)
         goto out;
     }
 
-    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);
+    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) {

99 lines not on this page · raw message

index 15d466356e..0485acdfc8 100644
@@ -637,21 +637,52 @@ static void vhost_commit(MemoryListener *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->memory_changed) {
-        goto out;
+    if (dev->n_mem_sections != n_old_sections) {
+        changed = true;
+    } else {
+        /* Same size, lets check the contents */
+        changed = n_old_sections && memcmp(dev->mem_sections, old_sections,
+                         n_old_sections * sizeof(old_sections[0])) != 0;
     }
-    if (!dev->started) {
+
+    trace_vhost_commit(dev->started, changed);
+    if (!changed) {
         goto out;
     }
-    if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) {
+
+    /* 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;
+    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;
     }
 

index 0485acdfc8..b2a8dd189f 100644
@@ -155,160 +155,6 @@ static void vhost_log_sync_range(struct vhost_dev *dev,
     }
 }
 
-/* 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 (dev->vhost_ops->vhost_backend_can_merge &&
-            !dev->vhost_ops->vhost_backend_can_merge(dev, uaddr, size,
-                                                     reg->userspace_addr,
-                                                     reg->memory_size)) {
-            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;

@@ -525,95 +371,6 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
     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) &&

@@ -624,8 +381,6 @@ 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;
     dev->tmp_sections = NULL;
     dev->n_tmp_sections = 0;
 }

@@ -701,7 +456,6 @@ static void vhost_commit(MemoryListener *listener)
         if (r < 0) {
             VHOST_OPS_DEBUG("vhost_set_mem_table failed");
         }
-        dev->memory_changed = false;
         goto out;
     }
     log_size = vhost_get_log_size(dev);

@@ -720,7 +474,6 @@ static void vhost_commit(MemoryListener *listener)
     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
         vhost_dev_log_resize(dev, log_size);
     }
-    dev->memory_changed = false;
 
 out:
     /* Deref the old list of sections, this must happen _after_ the

@@ -811,8 +564,6 @@ static void vhost_region_add(MemoryListener *listener,
         return;
     }
     vhost_region_add_section(dev, section);
-
-    vhost_set_memory(listener, section, true);
 }
 
 /* Called on regions that have not changed */

@@ -836,7 +587,6 @@ static void vhost_region_del(MemoryListener *listener,
         return;
     }
 
-    vhost_set_memory(listener, section, false);
 }
 
 static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)

@@ -1451,7 +1201,6 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     hdev->log_size = 0;
     hdev->log_enabled = false;
     hdev->started = false;
-    hdev->memory_changed = false;
     memory_listener_register(&hdev->memory_listener, &address_space_memory);
     QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
     return 0;

index 21f3022499..b64732420a 100644
@@ -69,9 +69,6 @@ struct vhost_dev {
     bool log_enabled;
     uint64_t log_size;
     Error *migration_blocker;
-    bool memory_changed;
-    hwaddr mem_changed_start_addr;
-    hwaddr mem_changed_end_addr;
     const VhostOps *vhost_ops;
     void *opaque;
     struct vhost_log *log;

index b2a8dd189f..5819ac6de7 100644
@@ -554,8 +554,9 @@ static void vhost_region_add_section(struct vhost_dev *dev,
     }
 }
 
-static void vhost_region_add(MemoryListener *listener,
-                             MemoryRegionSection *section)
+/* 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);

@@ -566,29 +567,6 @@ static void vhost_region_add(MemoryListener *listener,
     vhost_region_add_section(dev, section);
 }
 
-/* Called on regions that have not changed */
-static void vhost_region_nop(MemoryListener *listener,
-                             MemoryRegionSection *section)
-{
-    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
-                                         memory_listener);
-
-    if (!vhost_section(section)) {
-        return;
-    }
-
-    vhost_region_add_section(dev, section);
-}
-
-static void vhost_region_del(MemoryListener *listener,
-                             MemoryRegionSection *section)
-{
-    if (!vhost_section(section)) {
-        return;
-    }
-
-}
-
 static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
 {
     struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n);

@@ -1157,9 +1135,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     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,
+        .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,

index 5819ac6de7..49625aade2 100644
@@ -27,6 +27,7 @@
 #include "hw/virtio/virtio-access.h"
 #include "migration/blocker.h"
 #include "sysemu/dma.h"
+#include "trace.h"
 
 /* enabled until disconnected backend stabilizes */
 #define _VHOST_DEBUG 1

@@ -373,8 +374,19 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
 
 static bool vhost_section(MemoryRegionSection *section)
 {
-    return memory_region_is_ram(section->mr) &&
+    bool result;
+    bool log_dirty = memory_region_get_dirty_log_mask(section->mr) &
+                     ~(1 << DIRTY_MEMORY_MIGRATION);
+    result = memory_region_is_ram(section->mr) &&
         !memory_region_is_rom(section->mr);
+
+    /* Vhost doesn't handle any block which is doing dirty-tracking other
+     * than migration; this typically fires on VGA areas.
+     */
+    result &= !log_dirty;
+
+    trace_vhost_section(section->mr->name, result);
+    return result;
 }
 
 static void vhost_begin(MemoryListener *listener)

@@ -504,12 +516,6 @@ static void vhost_region_add_section(struct vhost_dev *dev,
     trace_vhost_region_add_section(section->mr->name, mrs_gpa, mrs_size,
                                    mrs_host);
 
-    bool log_dirty = memory_region_get_dirty_log_mask(section->mr) &
-                        ~(1 << DIRTY_MEMORY_MIGRATION);
-    if (log_dirty) {
-        return;
-    }
-
     if (dev->n_tmp_sections) {
         /* Since we already have at least one section, lets see if
          * this extends it; since we're scanning in order, we only