diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index feae646e09..1b56065a80 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -1941,8 +1941,8 @@ def cgen(code, **kwds):
     if indent_level:
         indent = genindent(indent_level)
         # re.subn() lacks flags support before Python 2.7, use re.compile()
-        raw = re.subn(re.compile(r'^.', re.MULTILINE),
-                      indent + r'\g<0>', raw)
+        raw = re.subn(re.compile(r'^(?!(#|$))', re.MULTILINE),
+                      indent, raw)
         raw = raw[0]
     return re.sub(re.escape(eatspace) + r' *', '', raw)