This patch introduces new VhostOps vhost_get_device_id callback which
can get the device id from backend

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 include/hw/virtio/vhost-backend.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index fa84abac97..bfc24207e2 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -118,6 +118,9 @@ typedef int (*vhost_dev_start_op)(struct vhost_dev *dev, bool started);
 typedef int (*vhost_vq_get_addr_op)(struct vhost_dev *dev,
                     struct vhost_vring_addr *addr,
                     struct vhost_virtqueue *vq);
+
+typedef int (*vhost_get_device_id_op)(struct vhost_dev *dev, uint32_t *dev_id);
+
 typedef struct VhostOps {
     VhostBackendType backend_type;
     vhost_backend_init vhost_backend_init;
@@ -160,6 +163,7 @@ typedef struct VhostOps {
     vhost_set_inflight_fd_op vhost_set_inflight_fd;
     vhost_dev_start_op vhost_dev_start;
     vhost_vq_get_addr_op  vhost_vq_get_addr;
+    vhost_get_device_id_op vhost_get_device_id;
 } VhostOps;
 
 extern const VhostOps user_ops;
-- 
2.21.1