diff --git a/qemu/scripts/qapi/visit.py b/qemu/scripts/qapi/visit.py
index 74cf7a36..419a58bb 100644
--- a/qemu/scripts/qapi/visit.py
+++ b/qemu/scripts/qapi/visit.py
@@ -293,7 +293,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
 #include "qapi/qmp/qerror.h"
 #include "%(visit)s.h"
 ''',
-                                      visit=visit, prefix=self._prefix))
+                                      visit=visit))
         self._genh.preamble_add(mcgen('''
 #include "qapi/qapi-builtin-visit.h"
 #include "%(types)s.h"