diff -r f531ed84b066 xen/arch/x86/mm/p2m-ept.c
--- a/xen/arch/x86/mm/p2m-ept.c	Tue May 17 17:32:19 2011 +0100
+++ b/xen/arch/x86/mm/p2m-ept.c	Mon May 23 11:52:32 2011 +0100
@@ -586,6 +586,11 @@ static mfn_t ept_get_entry(struct p2m_do
         *t = ept_entry->sa_p2mt;
         *a = ept_entry->access;
 
+        if ( p2m_has_emt(ept_entry->sa_p2mt) 
+             && (!is_epte_present(ept_entry) || ept_entry->mfn == 0) )
+            printk("Bad EPT entry %"PRIx64" for GFN %lx\n", 
+                   ept_entry->epte, gfn)
+
         mfn = _mfn(ept_entry->mfn);
         if ( i )
         {
@@ -736,7 +741,7 @@ void ept_change_entry_emt_with_range(str
         uint64_t trunk = 0;
 
         e = ept_get_entry_content(p2m, gfn, &level);
-        if ( !p2m_has_emt(e.sa_p2mt) )
+        if ( !is_epte_present(&e) || !p2m_has_emt(e.sa_p2mt) )
             continue;
 
         order = 0;