1 files changed, 25 insertions, 7 deletions

diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index f3214e1c57..d55de4c8ca 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -71,12 +71,26 @@ static void virtio_scsi_dataplane_stop_bh(void *opaque)
 {
     VirtIOSCSI *s = opaque;
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
+    EventNotifier *host_notifier;
     int i;
 
     virtio_queue_aio_detach_host_notifier(vs->ctrl_vq, s->ctx);
+    host_notifier = virtio_queue_get_host_notifier(vs->ctrl_vq);
+
+    /*
+     * Test and clear notifier after disabling event, in case poll callback
+     * didn't have time to run.
+     */
+    virtio_queue_host_notifier_read(host_notifier);
+
     virtio_queue_aio_detach_host_notifier(vs->event_vq, s->ctx);
+    host_notifier = virtio_queue_get_host_notifier(vs->event_vq);
+    virtio_queue_host_notifier_read(host_notifier);
+
     for (i = 0; i < vs->conf.num_queues; i++) {
         virtio_queue_aio_detach_host_notifier(vs->cmd_vqs[i], s->ctx);
+        host_notifier = virtio_queue_get_host_notifier(vs->cmd_vqs[i]);
+        virtio_queue_host_notifier_read(host_notifier);
     }
 }
 
@@ -144,14 +158,16 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
     s->dataplane_starting = false;
     s->dataplane_started = true;
 
-    aio_context_acquire(s->ctx);
-    virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx);
-    virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx);
+    if (s->bus.drain_count == 0) {
+        aio_context_acquire(s->ctx);
+        virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx);
+        virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx);
 
-    for (i = 0; i < vs->conf.num_queues; i++) {
-        virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx);
+        for (i = 0; i < vs->conf.num_queues; i++) {
+            virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx);
+        }
+        aio_context_release(s->ctx);
     }
-    aio_context_release(s->ctx);
     return 0;
 
 fail_host_notifiers:
@@ -197,7 +213,9 @@ void virtio_scsi_dataplane_stop(VirtIODevice *vdev)
     }
     s->dataplane_stopping = true;
 
-    aio_wait_bh_oneshot(s->ctx, virtio_scsi_dataplane_stop_bh, s);
+    if (s->bus.drain_count == 0) {
+        aio_wait_bh_oneshot(s->ctx, virtio_scsi_dataplane_stop_bh, s);
+    }
 
     blk_drain_all(); /* ensure there are no in-flight requests */