From 6269fe2bdf5cb4efc67c5fc61aea8212869320c8 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@cloudius-systems.com>
Date: Sun, 2 Nov 2014 15:43:20 +0200
Subject: [PATCH] xen: fix virt_to_mfn()

Need to shift by 12 to get to a frame number.  With this the host accepts
the guest interface.
---
 core/xen/gntalloc.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/xen/gntalloc.cc b/core/xen/gntalloc.cc
index 56301c56ee..dca205407c 100644
--- a/core/xen/gntalloc.cc
+++ b/core/xen/gntalloc.cc
@@ -116,7 +116,7 @@ public:
 // and in that case we'll need to have an extra step here
 inline uint64_t
 virt_to_mfn(void *virt) {
-    return virt_to_phys(virt);
+    return virt_to_phys(virt) >> 12;
 }
 
 gntref& kernel_grant_head::new_ref() {