diff --git a/hw/input/adb.c b/hw/input/adb.c
index 013fcc9c54..84331b9fce 100644
--- a/hw/input/adb.c
+++ b/hw/input/adb.c
@@ -309,6 +309,7 @@ static void adb_device_class_init(ObjectClass *oc, void *data)
 static const TypeInfo adb_device_type_info = {
     .name = TYPE_ADB_DEVICE,
     .parent = TYPE_DEVICE,
+    .class_size = sizeof(ADBDeviceClass),
     .instance_size = sizeof(ADBDevice),
     .abstract = true,
     .class_init = adb_device_class_init,