virtio-rng: use aliases instead of duplicate qdev properties

virtio-rng-{pci, s390, ccw} all duplicate the
qdev properties of their VirtIORNG child.
This approach does not work well with string or pointer
properties since we must be careful about leaking or
double-freeing them.

Use the QOM alias property to forward property accesses to the
VirtIORNG child.  This way no duplication is necessary.
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 8ee486ae)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

hw/s390x/s390-virtio-bus.c

@@ -311,6 +311,7 @@ static void s390_virtio_rng_instance_init(Object *obj)
     VirtIORNGS390 *dev = VIRTIO_RNG_S390(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng,
                              qdev_prop_allow_set_link_before_realize,
@@ -561,7 +562,6 @@ static const TypeInfo s390_virtio_serial = {
 
 static Property s390_virtio_rng_properties[] = {
     DEFINE_VIRTIO_COMMON_FEATURES(VirtIOS390Device, host_features),
-    DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNGS390, vdev.conf),
     DEFINE_PROP_END_OF_LIST(),
 };
 

hw/s390x/virtio-ccw.c

@@ -1542,6 +1542,7 @@ static void virtio_ccw_rng_instance_init(Object *obj)
     VirtIORNGCcw *dev = VIRTIO_RNG_CCW(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng,
                              qdev_prop_allow_set_link_before_realize,
@@ -1550,7 +1551,6 @@ static void virtio_ccw_rng_instance_init(Object *obj)
 
 static Property virtio_ccw_rng_properties[] = {
     DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
-    DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNGCcw, vdev.conf),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_END_OF_LIST(),

hw/virtio/virtio-pci.c

@@ -1485,7 +1485,6 @@ static const TypeInfo virtio_net_pci_info = {
 /* virtio-rng-pci */
 
 static Property virtio_rng_pci_properties[] = {
-    DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORngPCI, vdev.conf),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -1527,6 +1526,7 @@ static void virtio_rng_initfn(Object *obj)
     VirtIORngPCI *dev = VIRTIO_RNG_PCI(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng,
                              qdev_prop_allow_set_link_before_realize,