Fix fixup of invalid PTE writes, broken by 13392:0fd65225e4c6.

By the time we test if addr is the upper word it has already been
aligned to the 8 byte pte size.

Signed-off-by: Ian Campbell <ian.campbell@xensource.com>

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index c86a895819f3ee02c39f164fa8f3d5de916cf506..29bfd5f878198449cb943ad6c5156748fc14d03c 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -3240,6 +3240,7 @@ static int ptwr_emulated_update(
     struct ptwr_emulate_ctxt *ptwr_ctxt)
 {
     unsigned long mfn;
+    unsigned long unaligned_addr = addr;
     struct page_info *page;
     l1_pgentry_t pte, ol1e, nl1e, *pl1e;
     struct vcpu *v = current;
@@ -3294,7 +3295,7 @@ static int ptwr_emulated_update(
     if ( unlikely(!get_page_from_l1e(nl1e, d)) )
     {
         if ( (CONFIG_PAGING_LEVELS >= 3) && is_pv_32bit_domain(d) &&
-             (bytes == 4) && (addr & 4) && !do_cmpxchg &&
+             (bytes == 4) && (unaligned_addr & 4) && !do_cmpxchg &&
              (l1e_get_flags(nl1e) & _PAGE_PRESENT) )
         {
             /*