diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index e978bfe760..cb44e19b67 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1935,6 +1935,7 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t)
         .parent        = t->parent ? t->parent : TYPE_VIRTIO_PCI,
         .instance_size = t->instance_size,
         .instance_init = t->instance_init,
+        .class_size    = t->class_size,
         .class_init    = virtio_pci_base_class_init,
         .class_data    = (void *)t,
         .abstract      = true,
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index bd223a6e3b..18581854ca 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -230,6 +230,7 @@ typedef struct VirtioPCIDeviceTypeInfo {
 
     /* Same as TypeInfo fields: */
     size_t instance_size;
+    size_t class_size;
     void (*instance_init)(Object *obj);
     void (*class_init)(ObjectClass *klass, void *data);
 } VirtioPCIDeviceTypeInfo;