diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 96b0c4c720..40a7b8c2c9 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -49,6 +49,8 @@
 
 #ifdef MAX_PHYS_CPUS
 #define NR_CPUS MAX_PHYS_CPUS
+#elif defined __i386__
+#define NR_CPUS 128
 #else
 #define NR_CPUS 256
 #endif