--- a/arch/x86/xen/setup.c	2011-01-05 00:50:19.000000000 +0000
+++ b/arch/x86/xen/setup.c	2011-01-24 20:29:23.000000000 +0000
@@ -179,7 +179,10 @@
 	e820.nr_map = 0;
 	xen_extra_mem_start = mem_end;
 	for (i = 0; i < memmap.nr_entries; i++) {
-		unsigned long long end = map[i].addr + map[i].size;
+		unsigned long long end;
+		if (map[i].type == E820_RAM)
+			map[i].size &= ~(PAGE_SIZE-1);
+		end = map[i].addr + map[i].size;
 
 		if (map[i].type == E820_RAM && end > mem_end) {
 			/* RAM off the end - may be partially included */