diff --git a/MAINTAINERS b/MAINTAINERS
index d8a02a6c19..a0805d35cd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -601,6 +601,7 @@ F:	xen/arch/x86/
 F:	xen/include/public/arch-x86/
 F:	xen/include/xen/lib/x86
 F:	xen/lib/x86
+F:	xen/tools/gen-cpuid.py
 F:	tools/firmware/hvmloader/
 F:	tools/firmware/rombios/
 F:	tools/firmware/vgabios/
diff --git a/xen/tools/gen-cpuid.py b/xen/tools/gen-cpuid.py
index 72cf11654b..4a1ca58905 100755
--- a/xen/tools/gen-cpuid.py
+++ b/xen/tools/gen-cpuid.py
@@ -363,8 +363,8 @@ def crunch_numbers(state):
     state.deep_features = deps.keys()
     state.nr_deep_deps = len(state.deep_deps.keys())
 
-    # Calculate the bitfield name declarations
-    for word in range(state.nr_entries):
+    # Calculate the bitfield name declarations.  Leave 4 placeholders on the end
+    for word in range(state.nr_entries + 4):
 
         names = []
         for bit in range(32):
@@ -382,7 +382,10 @@ def crunch_numbers(state):
 
             names.append(name.lower())
 
-        state.bitfields.append("bool " + ":1, ".join(names) + ":1")
+        if any(names):
+            state.bitfields.append("bool " + ":1, ".join(names) + ":1")
+        else:
+            state.bitfields.append("uint32_t _placeholder_%u" % (word, ))
 
 
 def write_results(state):
@@ -464,8 +467,6 @@ def write_results(state):
 
 """)
 
-    state.bitfields += ["uint32_t :32 /* placeholder */"] * 4
-
     for idx, text in enumerate(state.bitfields):
         state.output.write(
             "#define CPUID_BITFIELD_%d \\\n    %s\n\n"