diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 3fee4aa3457004096b9c7564ec2cc1a5208684e2..ffbb9c2c89fdc0ef52a5a8e810b6fe94398889d4 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -898,9 +898,8 @@ static void balloon_ccw_stats_set_poll_interval(Object *obj, struct Visitor *v,
 static void virtio_ccw_balloon_instance_init(Object *obj)
 {
     VirtIOBalloonCcw *dev = VIRTIO_BALLOON_CCW(obj);
-    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BALLOON);
-    object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
-    object_unref(OBJECT(&dev->vdev));
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VIRTIO_BALLOON);
     object_property_add(obj, "guest-stats", "guest statistics",
                         balloon_ccw_stats_get_all, NULL, NULL, dev, NULL);
 
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 6dd41b992f80009413b79eee96dafeb8403dd4cf..e7baf7b5e8f957cd9705baf23f94b680402c152f 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1274,9 +1274,8 @@ static void virtio_balloon_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_balloon_pci_instance_init(Object *obj)
 {
     VirtIOBalloonPCI *dev = VIRTIO_BALLOON_PCI(obj);
-    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BALLOON);
-    object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
-    object_unref(OBJECT(&dev->vdev));
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VIRTIO_BALLOON);
     object_property_add(obj, "guest-stats", "guest statistics",
                         balloon_pci_stats_get_all, NULL, NULL, dev,
                         NULL);