xen: fix truncation of machine address

arbitrary_virt_to_machine can truncate a machine address if its above
4G.  Cast the problem away.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 2579e70cdd08..05d7392a7a4c 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -186,7 +186,7 @@ xmaddr_t arbitrary_virt_to_machine(unsigned long address)
 
         BUG_ON(pte == NULL);
 
-        return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
+        return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
 }
 
 void make_lowmem_page_readonly(void *vaddr)