diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
index 87278f54e5..38d2ee3948 100644
--- a/hw/virtio-balloon.c
+++ b/hw/virtio-balloon.c
@@ -31,14 +31,6 @@
 
 #include "hw/virtio-bus.h"
 
-/*
- * Will be modified later in the serie.
- */
-static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
-{
-    return (VirtIOBalloon *)vdev;
-}
-
 static void balloon_page(void *addr, int deflate)
 {
 #if defined(__linux__)
@@ -74,7 +66,8 @@ static inline void reset_stats(VirtIOBalloon *dev)
 
 static bool balloon_stats_supported(const VirtIOBalloon *s)
 {
-    return s->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
 }
 
 static bool balloon_stats_enabled(const VirtIOBalloon *s)
@@ -100,6 +93,7 @@ static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
 static void balloon_stats_poll_cb(void *opaque)
 {
     VirtIOBalloon *s = opaque;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 
     if (!balloon_stats_supported(s)) {
         /* re-schedule */
@@ -108,7 +102,7 @@ static void balloon_stats_poll_cb(void *opaque)
     }
 
     virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
-    virtio_notify(&s->vdev, s->svq);
+    virtio_notify(vdev, s->svq);
 }
 
 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
@@ -186,7 +180,7 @@ static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 
 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
-    VirtIOBalloon *s = to_virtio_balloon(vdev);
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
     VirtQueueElement elem;
     MemoryRegionSection section;
 
@@ -220,7 +214,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 
 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 {
-    VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev);
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
     VirtQueueElement *elem = &s->stats_vq_elem;
     VirtIOBalloonStat stat;
     size_t offset = 0;
@@ -262,7 +256,7 @@ out:
 
 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 {
-    VirtIOBalloon *dev = to_virtio_balloon(vdev);
+    VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
     struct virtio_balloon_config config;
 
     config.num_pages = cpu_to_le32(dev->num_pages);
@@ -274,7 +268,7 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 static void virtio_balloon_set_config(VirtIODevice *vdev,
                                       const uint8_t *config_data)
 {
-    VirtIOBalloon *dev = to_virtio_balloon(vdev);
+    VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
     struct virtio_balloon_config config;
     uint32_t oldactual = dev->actual;
     memcpy(&config, config_data, 8);
@@ -300,22 +294,24 @@ static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 
 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 {
-    VirtIOBalloon *dev = opaque;
+    VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 
     if (target > ram_size) {
         target = ram_size;
     }
     if (target) {
         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
-        virtio_notify_config(&dev->vdev);
+        virtio_notify_config(vdev);
     }
 }
 
 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 {
-    VirtIOBalloon *s = opaque;
+    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 
-    virtio_save(&s->vdev, f);
+    virtio_save(vdev, f);
 
     qemu_put_be32(f, s->num_pages);
     qemu_put_be32(f, s->actual);
@@ -323,13 +319,14 @@ static void virtio_balloon_save(QEMUFile *f, void *opaque)
 
 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 {
-    VirtIOBalloon *s = opaque;
+    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
     int ret;
 
     if (version_id != 1)
         return -EINVAL;
 
-    ret = virtio_load(&s->vdev, f);
+    ret = virtio_load(vdev, f);
     if (ret) {
         return ret;
     }
@@ -347,9 +344,9 @@ static int virtio_balloon_device_init(VirtIODevice *vdev)
 
     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 8);
 
-    s->vdev.get_config = virtio_balloon_get_config;
-    s->vdev.set_config = virtio_balloon_set_config;
-    s->vdev.get_features = virtio_balloon_get_features;
+    vdev->get_config = virtio_balloon_get_config;
+    vdev->set_config = virtio_balloon_set_config;
+    vdev->get_features = virtio_balloon_get_features;
 
     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
                                    virtio_balloon_stat, s);
diff --git a/hw/virtio-balloon.h b/hw/virtio-balloon.h
index 139eac309e..5f8fe021d0 100644
--- a/hw/virtio-balloon.h
+++ b/hw/virtio-balloon.h
@@ -57,7 +57,7 @@ typedef struct VirtIOBalloonStat {
 } QEMU_PACKED VirtIOBalloonStat;
 
 typedef struct VirtIOBalloon {
-    VirtIODevice vdev;
+    VirtIODevice parent_obj;
     VirtQueue *ivq, *dvq, *svq;
     uint32_t num_pages;
     uint32_t actual;