diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 5f61469..ab52d1d 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -32,7 +32,7 @@ typedef struct VirtIOBlock
 
 static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
 {
-    return (VirtIOBlock *)vdev;
+    return container_of(vdev, VirtIOBlock, vdev);
 }
 
 typedef struct VirtIOBlockReq