diff --git a/xen/include/xen/types.h b/xen/include/xen/types.h
index 8596ded..ec992f8 100644
--- a/xen/include/xen/types.h
+++ b/xen/include/xen/types.h
@@ -58,5 +58,6 @@ typedef __u64 __le64;
 typedef __u64 __be64;
 
 typedef unsigned long uintptr_t;
+typedef int ssize_t;
 
 #endif /* __TYPES_H__ */