diff --git a/xen/common/compat/grant_table.c b/xen/common/compat/grant_table.c
index 744f9b6e3d..f8177c84c0 100644
--- a/xen/common/compat/grant_table.c
+++ b/xen/common/compat/grant_table.c
@@ -176,7 +176,12 @@ int compat_grant_table_op(
                     { \
                         for ( i = 0; i < (_s_)->nr_frames; ++i ) \
                         { \
-                            unsigned int frame = (_s_)->frame_list.p[i]; \
+                            compat_pfn_t frame = (_s_)->frame_list.p[i]; \
+                            if ( frame != (_s_)->frame_list.p[i] ) \
+                            { \
+                                (_s_)->status = GNTST_address_too_big; \
+                                break; \
+                            } \
                             if ( __copy_to_compat_offset((_d_)->frame_list, \
                                                          i, &frame, 1) ) \
                             { \