diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h
index a9984dbea5..775cf34c04 100644
--- a/tools/include/xenguest.h
+++ b/tools/include/xenguest.h
@@ -438,7 +438,7 @@ struct xenevtchn_handle;
 struct precopy_stats
 {
     unsigned int iteration;
-    unsigned int total_written;
+    unsigned long total_written;
     long dirty_count; /* -1 if unknown */
 };