diff options
| -rw-r--r-- | hw/virtio/virtio-mem.c | 54 | ||||
| -rw-r--r-- | include/hw/virtio/virtio-mem.h | 3 |
2 files changed, 56 insertions, 1 deletions
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 1ab9ef17fa..65850530e7 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -62,8 +62,14 @@ static bool virtio_mem_is_busy(void) /* * Postcopy cannot handle concurrent discards and we don't want to migrate * pages on-demand with stale content when plugging new blocks. + * + * For precopy, we don't want unplugged blocks in our migration stream, and + * when plugging new blocks, the page content might differ between source + * and destination (observable by the guest when not initializing pages + * after plugging them) until we're running on the destination (as we didn't + * migrate these blocks when they were unplugged). */ - return migration_in_incoming_postcopy(); + return migration_in_incoming_postcopy() || !migration_is_idle(); } static bool virtio_mem_test_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, @@ -475,6 +481,7 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) host_memory_backend_set_mapped(vmem->memdev, true); vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem)); qemu_register_reset(virtio_mem_system_reset, vmem); + precopy_add_notifier(&vmem->precopy_notifier); } static void virtio_mem_device_unrealize(DeviceState *dev) @@ -482,6 +489,7 @@ static void virtio_mem_device_unrealize(DeviceState *dev) VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOMEM *vmem = VIRTIO_MEM(dev); + precopy_remove_notifier(&vmem->precopy_notifier); qemu_unregister_reset(virtio_mem_system_reset, vmem); vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem)); host_memory_backend_set_mapped(vmem->memdev, false); @@ -757,12 +765,56 @@ static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name, vmem->block_size = value; } +static void virtio_mem_precopy_exclude_unplugged(VirtIOMEM *vmem) +{ + void * const host = qemu_ram_get_host_addr(vmem->memdev->mr.ram_block); + unsigned long first_zero_bit, last_zero_bit; + uint64_t offset, length; + + /* + * Find consecutive unplugged blocks and exclude them from migration. + * + * Note: Blocks cannot get (un)plugged during precopy, no locking needed. + */ + first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size); + while (first_zero_bit < vmem->bitmap_size) { + offset = first_zero_bit * vmem->block_size; + last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, + first_zero_bit + 1) - 1; + length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size; + + qemu_guest_free_page_hint(host + offset, length); + first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, + last_zero_bit + 2); + } +} + +static int virtio_mem_precopy_notify(NotifierWithReturn *n, void *data) +{ + VirtIOMEM *vmem = container_of(n, VirtIOMEM, precopy_notifier); + PrecopyNotifyData *pnd = data; + + switch (pnd->reason) { + case PRECOPY_NOTIFY_SETUP: + precopy_enable_free_page_optimization(); + break; + case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: + virtio_mem_precopy_exclude_unplugged(vmem); + break; + default: + break; + } + + return 0; +} + static void virtio_mem_instance_init(Object *obj) { VirtIOMEM *vmem = VIRTIO_MEM(obj); vmem->block_size = VIRTIO_MEM_MIN_BLOCK_SIZE; notifier_list_init(&vmem->size_change_notifiers); + vmem->precopy_notifier.notify = virtio_mem_precopy_notify; object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size, NULL, NULL, NULL); diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h index b74c77cd42..0778224964 100644 --- a/include/hw/virtio/virtio-mem.h +++ b/include/hw/virtio/virtio-mem.h @@ -67,6 +67,9 @@ typedef struct VirtIOMEM { /* notifiers to notify when "size" changes */ NotifierList size_change_notifiers; + + /* don't migrate unplugged memory */ + NotifierWithReturn precopy_notifier; } VirtIOMEM; typedef struct VirtIOMEMClass { |