diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 341c3fa2c1..ab975ff566 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -429,10 +429,40 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, return -EBUSY; } virtio_mem_notify_unplug(vmem, offset, size); - } else if (virtio_mem_notify_plug(vmem, offset, size)) { - /* Could be a mapping attempt resulted in memory getting populated. */ - ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); - return -EBUSY; + } else { + int ret = 0; + + if (vmem->prealloc) { + void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset; + int fd = memory_region_get_fd(&vmem->memdev->mr); + Error *local_err = NULL; + + os_mem_prealloc(fd, area, size, 1, &local_err); + if (local_err) { + static bool warned; + + /* + * Warn only once, we don't want to fill the log with these + * warnings. + */ + if (!warned) { + warn_report_err(local_err); + warned = true; + } else { + error_free(local_err); + } + ret = -EBUSY; + } + } + if (!ret) { + ret = virtio_mem_notify_plug(vmem, offset, size); + } + + if (ret) { + /* Could be preallocation or a notifier populated memory. */ + ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); + return -EBUSY; + } } virtio_mem_set_bitmap(vmem, start_gpa, size, plug); return 0; @@ -1108,6 +1138,7 @@ static void virtio_mem_instance_init(Object *obj) static Property virtio_mem_properties[] = { DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0), DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0), + DEFINE_PROP_BOOL(VIRTIO_MEM_PREALLOC_PROP, VirtIOMEM, prealloc, false), DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev, TYPE_MEMORY_BACKEND, HostMemoryBackend *), DEFINE_PROP_END_OF_LIST(), diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h index a5dd6a493b..0ac7bcb3b6 100644 --- a/include/hw/virtio/virtio-mem.h +++ b/include/hw/virtio/virtio-mem.h @@ -30,6 +30,7 @@ OBJECT_DECLARE_TYPE(VirtIOMEM, VirtIOMEMClass, #define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" #define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" #define VIRTIO_MEM_ADDR_PROP "memaddr" +#define VIRTIO_MEM_PREALLOC_PROP "prealloc" struct VirtIOMEM { VirtIODevice parent_obj; @@ -62,6 +63,9 @@ struct VirtIOMEM { /* block size and alignment */ uint64_t block_size; + /* whether to prealloc memory when plugging new blocks */ + bool prealloc; + /* notifiers to notify when "size" changes */ NotifierList size_change_notifiers;