[Xen-changelog] [xen-unstable] [XEN] Shadow: check the _PAGE_PRESENT bit in fast-path MMIO shadow ptes

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
# Date 1174497428 0
# Node ID e9a5ba5528087173f1d8fd7695434c8211f1c3b9
# Parent  c9ac275f8985ebaa1159fa6e01a10989fb704a39
[XEN] Shadow: check the _PAGE_PRESENT bit in fast-path MMIO shadow ptes
otherwise the fast-path code is not safe against some kinds of
concurrent shadow updates.
Signed-off-by: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
---
 xen/arch/x86/mm/shadow/types.h |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -r c9ac275f8985 -r e9a5ba552808 xen/arch/x86/mm/shadow/types.h
--- a/xen/arch/x86/mm/shadow/types.h    Wed Mar 21 12:03:42 2007 +0000
+++ b/xen/arch/x86/mm/shadow/types.h    Wed Mar 21 17:17:08 2007 +0000
@@ -597,7 +597,7 @@ accumulate_guest_flags(struct vcpu *v, w
  * have reserved bits that we can use for this.
  */
 
-#define SH_L1E_MAGIC 0xffffffff00000000ULL
+#define SH_L1E_MAGIC 0xffffffff00000001ULL
 static inline int sh_l1e_is_magic(shadow_l1e_t sl1e)
 {
     return ((sl1e.l1 & SH_L1E_MAGIC) == SH_L1E_MAGIC);

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