From: Xueming Li <xuemingl@nvidia.com>

In case of device resume after suspend, VQ notifier MR still valid.
Duplicated registrations explode memory block list and slow down device
resume.

Fixes: 44866521bd6e ("vhost-user: support registering external host notifiers")
Cc: tiwei.bie@intel.com
Cc: qemu-stable@nongnu.org
Cc: Yuwei Zhang <zhangyuwei.9149@bytedance.com>

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Message-Id: <20211008080215.590292-1-xuemingl@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit a1ed9ef1de87c3e86ff68589604298ec90875a14)
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 hw/virtio/vhost-user.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index aec6cc1990..7b35c5d71d 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1469,8 +1469,9 @@ static int vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev,
 
     name = g_strdup_printf("vhost-user/host-notifier@%p mmaps[%d]",
                            user, queue_idx);
-    memory_region_init_ram_device_ptr(&n->mr, OBJECT(vdev), name,
-                                      page_size, addr);
+    if (!n->mr.ram) /* Don't init again after suspend. */
+        memory_region_init_ram_device_ptr(&n->mr, OBJECT(vdev), name,
+                                          page_size, addr);
     g_free(name);
 
     if (virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, true)) {
-- 
2.25.1