hw/xen: Prefer QOM cast for XenLegacyDevice

Makes the code less sensitive regarding changes in the class hierarchy which
will be performed in the next patch.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250127094129.15941-1-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/usb/xen-usb.c

@@ -755,10 +755,10 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
 
     qdict = qdict_new();
     qdict_put_str(qdict, "driver", "usb-host");
-    tmp = g_strdup_printf("%s.0", usbif->xendev.qdev.id);
+    tmp = g_strdup_printf("%s.0", DEVICE(&usbif->xendev)->id);
     qdict_put_str(qdict, "bus", tmp);
     g_free(tmp);
-    tmp = g_strdup_printf("%s-%u", usbif->xendev.qdev.id, port);
+    tmp = g_strdup_printf("%s-%u", DEVICE(&usbif->xendev)->id, port);
     qdict_put_str(qdict, "id", tmp);
     g_free(tmp);
     qdict_put_int(qdict, "port", port);
@@ -1022,7 +1022,7 @@ static void usbback_alloc(struct XenLegacyDevice *xendev)
     usbif = container_of(xendev, struct usbback_info, xendev);
 
     usb_bus_new(&usbif->bus, sizeof(usbif->bus), &xen_usb_bus_ops,
-                DEVICE(&xendev->qdev));
+                DEVICE(xendev));
     for (i = 0; i < USBBACK_MAXPORTS; i++) {
         p = &(usbif->ports[i].port);
         usb_register_port(&usbif->bus, p, usbif, i, &xen_usb_port_ops,

hw/xen/xen-legacy-backend.c

@@ -163,7 +163,7 @@ static struct XenLegacyDevice *xen_be_get_xendev(const char *type, int dom,
 
     /* init new xendev */
     xendev = g_malloc0(ops->size);
-    object_initialize(&xendev->qdev, ops->size, TYPE_XENBACKEND);
+    object_initialize(xendev, ops->size, TYPE_XENBACKEND);
     OBJECT(xendev)->free = g_free;
     qdev_set_id(DEVICE(xendev), g_strdup_printf("xen-%s-%d", type, dev),
                 &error_fatal);

hw/xen/xen_pvdev.c

@@ -273,7 +273,7 @@ void xen_pv_del_xendev(struct XenLegacyDevice *xendev)
 
     QTAILQ_REMOVE(&xendevs, xendev, next);
 
-    qdev_unplug(&xendev->qdev, NULL);
+    qdev_unplug(DEVICE(xendev), NULL);
 }
 
 void xen_pv_insert_xendev(struct XenLegacyDevice *xendev)