virtio-serial: use aliases instead of duplicate qdev properties

virtio-serial-{pci, s390, ccw} all duplicate the
qdev properties of their VirtIOSerial 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
VirtIOSerial child.  This way no duplication is necessary.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/s390x/s390-virtio-bus.c

@@ -226,6 +226,7 @@ static void s390_virtio_serial_instance_init(Object *obj)
     VirtIOSerialS390 *dev = VIRTIO_SERIAL_S390(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static int s390_virtio_scsi_init(VirtIOS390Device *s390_dev)
@@ -537,7 +538,6 @@ static const TypeInfo s390_virtio_blk = {
 };
 
 static Property s390_virtio_serial_properties[] = {
-    DEFINE_VIRTIO_SERIAL_PROPERTIES(VirtIOSerialS390, vdev.serial),
     DEFINE_PROP_END_OF_LIST(),
 };
 

hw/s390x/virtio-ccw.c

@@ -852,6 +852,7 @@ static void virtio_ccw_serial_instance_init(Object *obj)
     VirtioSerialCcw *dev = VIRTIO_SERIAL_CCW(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static int virtio_ccw_balloon_init(VirtioCcwDevice *ccw_dev)
@@ -1432,7 +1433,6 @@ static const TypeInfo virtio_ccw_blk = {
 
 static Property virtio_ccw_serial_properties[] = {
     DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
-    DEFINE_VIRTIO_SERIAL_PROPERTIES(VirtioSerialCcw, vdev.serial),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_END_OF_LIST(),

hw/virtio/virtio-pci.c

@@ -1387,7 +1387,6 @@ static Property virtio_serial_pci_properties[] = {
                     VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
     DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
-    DEFINE_VIRTIO_SERIAL_PROPERTIES(VirtIOSerialPCI, vdev.serial),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -1410,6 +1409,7 @@ static void virtio_serial_pci_instance_init(Object *obj)
     VirtIOSerialPCI *dev = VIRTIO_SERIAL_PCI(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static const TypeInfo virtio_serial_pci_info = {