1 files changed, 17 insertions, 6 deletions

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index af1c24c..b90456c 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -246,13 +246,15 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
     }
 
     /* Get this show started by hooking up our callbacks */
-    aio_context_acquire(s->ctx);
-    for (i = 0; i < nvqs; i++) {
-        VirtQueue *vq = virtio_get_queue(s->vdev, i);
+    if (!blk_in_drain(s->conf->conf.blk)) {
+        aio_context_acquire(s->ctx);
+        for (i = 0; i < nvqs; i++) {
+            VirtQueue *vq = virtio_get_queue(s->vdev, i);
 
-        virtio_queue_aio_attach_host_notifier(vq, s->ctx);
+            virtio_queue_aio_attach_host_notifier(vq, s->ctx);
+        }
+        aio_context_release(s->ctx);
     }
-    aio_context_release(s->ctx);
     return 0;
 
   fail_aio_context:
@@ -287,8 +289,15 @@ static void virtio_blk_data_plane_stop_bh(void *opaque)
 
     for (i = 0; i < s->conf->num_queues; i++) {
         VirtQueue *vq = virtio_get_queue(s->vdev, i);
+        EventNotifier *host_notifier = virtio_queue_get_host_notifier(vq);
 
         virtio_queue_aio_detach_host_notifier(vq, s->ctx);
+
+        /*
+         * Test and clear notifier after disabling event, in case poll callback
+         * didn't have time to run.
+         */
+        virtio_queue_host_notifier_read(host_notifier);
     }
 }
 
@@ -315,7 +324,9 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev)
     s->stopping = true;
     trace_virtio_blk_data_plane_stop(s);
 
-    aio_wait_bh_oneshot(s->ctx, virtio_blk_data_plane_stop_bh, s);
+    if (!blk_in_drain(s->conf->conf.blk)) {
+        aio_wait_bh_oneshot(s->ctx, virtio_blk_data_plane_stop_bh, s);
+    }
 
     aio_context_acquire(s->ctx);