diff -r ae0e96e156f3 xen/arch/x86/mm/p2m-pt.c
--- a/xen/arch/x86/mm/p2m-pt.c	Thu Jul 19 12:12:12 2012 +0200
+++ b/xen/arch/x86/mm/p2m-pt.c	Fri Jul 20 15:39:54 2012 +0200
@@ -88,7 +88,7 @@ static unsigned long p2m_type_to_flags(p
     case p2m_ram_paged:
     case p2m_ram_paging_in:
     default:
-        return flags;
+        return flags | _PAGE_NX_BIT;
     case p2m_grant_map_ro:
         return flags | P2M_BASE_FLAGS | _PAGE_NX_BIT;
     case p2m_ram_ro: