diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 084f5e7..d1b8abe 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -1209,7 +1209,15 @@
                                    int required_for_version,
                                    Error **errp);
 
-/* Returns: 0 on success, -1 on failure */
+/**
+ * vmstate_register() - legacy function to register state
+ * serialisation description
+ *
+ * New code shouldn't be using this function as QOM-ified devices have
+ * dc->vmsd to store the serialisation description.
+ *
+ * Returns: 0 on success, -1 on failure
+ */
 static inline int vmstate_register(VMStateIf *obj, int instance_id,
                                    const VMStateDescription *vmsd,
                                    void *opaque)