diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c
index 3a02e224e8..54d0166b85 100644
--- a/src/util/virhostcpu.c
+++ b/src/util/virhostcpu.c
@@ -1672,9 +1672,10 @@ virHostCPUGetSignature(char **signature)
 }
 
 int
-virHostCPUGetPhysAddrSize(unsigned int *size)
+virHostCPUGetPhysAddrSize(unsigned int *size G_GNUC_UNUSED)
 {
-    return 0;
+    errno = ENOSYS;
+    return -1;
 }
 
 #endif /* __linux__ */