diff -r 61c96456a3e1 include/xen/interface/xen.h
--- a/include/xen/interface/xen.h	Thu Dec 20 16:58:14 2007 +0000
+++ b/include/xen/interface/xen.h	Sat Jan 12 20:01:14 2008 -0700
@@ -168,9 +168,13 @@
  * ptr[:2]  -- Machine address within the frame whose mapping to modify.
  *             The frame must belong to the FD, if one is specified.
  * val      -- Value to write into the mapping entry.
+ *
+ * ptr[1:0] == MMU_PT_UPDATE_PRESERVE_AD:
+ * As MMU_NORMAL_PT_UPDATE above, but A/D bits in the PTE are preserved (ORed).
  */
-#define MMU_NORMAL_PT_UPDATE     0 /* checked '*ptr = val'. ptr is MA.       */
-#define MMU_MACHPHYS_UPDATE      1 /* ptr = MA of frame to modify entry for  */
+#define MMU_NORMAL_PT_UPDATE      0 /* checked '*ptr = val'. ptr is MA.      */
+#define MMU_MACHPHYS_UPDATE       1 /* ptr = MA of frame to modify entry for */
+#define MMU_PT_UPDATE_PRESERVE_AD 2 /* '*ptr = val', preserve (OR) A/D bits  */
 
 /*
  * MMU EXTENDED OPERATIONS
diff -r 61c96456a3e1 include/asm-i386/mach-xen/asm/pgtable.h
--- a/include/asm-i386/mach-xen/asm/pgtable.h	Thu Dec 20 16:58:14 2007 +0000
+++ b/include/asm-i386/mach-xen/asm/pgtable.h	Mon Jan 07 17:47:31 2008 -0700
@@ -512,6 +512,12 @@ int touch_pte_range(struct mm_struct *mm
                     unsigned long address,
                     unsigned long size);
 
+int xen_change_pte_range(struct mm_struct *mm, pmd_t *pmd,
+		unsigned long addr, unsigned long end, pgprot_t newprot);
+
+#define arch_change_pte_range(mm, pmd, addr, end, newprot)	\
+		xen_change_pte_range(mm, pmd, addr, end, newprot)
+
 #define io_remap_pfn_range(vma,from,pfn,size,prot) \
 direct_remap_pfn_range(vma,from,pfn,size,prot,DOMID_IO)
 
diff -r 61c96456a3e1 include/asm-x86_64/mach-xen/asm/pgtable.h
--- a/include/asm-x86_64/mach-xen/asm/pgtable.h	Thu Dec 20 16:58:14 2007 +0000
+++ b/include/asm-x86_64/mach-xen/asm/pgtable.h	Mon Jan 07 17:47:41 2008 -0700
@@ -541,6 +541,12 @@ int touch_pte_range(struct mm_struct *mm
                     unsigned long address,
                     unsigned long size);
 
+int xen_change_pte_range(struct mm_struct *mm, pmd_t *pmd,
+		unsigned long addr, unsigned long end, pgprot_t newprot);
+
+#define arch_change_pte_range(mm, pmd, addr, end, newprot)	\
+		xen_change_pte_range(mm, pmd, addr, end, newprot)
+
 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
 		direct_remap_pfn_range(vma,vaddr,pfn,size,prot,DOMID_IO)
 
diff -r 61c96456a3e1 include/asm-generic/pgtable.h
--- a/include/asm-generic/pgtable.h	Thu Dec 20 16:58:14 2007 +0000
+++ b/include/asm-generic/pgtable.h	Mon Jan 07 17:48:00 2008 -0700
@@ -188,6 +188,10 @@ static inline void ptep_set_wrprotect(st
 })
 #endif
 
+#ifndef arch_change_pte_range
+#define arch_change_pte_range(mm, pmd, addr, end, newprot) 0
+#endif
+
 #ifndef __ASSEMBLY__
 /*
  * When walking page tables, we usually want to skip any p?d_none entries;
diff -r 61c96456a3e1 arch/i386/mm/hypervisor.c
--- a/arch/i386/mm/hypervisor.c	Thu Dec 20 16:58:14 2007 +0000
+++ b/arch/i386/mm/hypervisor.c	Sat Jan 12 20:01:40 2008 -0700
@@ -548,3 +548,33 @@ int write_ldt_entry(void *ldt, int entry
 		mach_lp, (u64)entry_a | ((u64)entry_b<<32));
 }
 #endif
+
+#define MAX_BATCHED_FULL_PTES 32
+
+int xen_change_pte_range(struct mm_struct *mm, pmd_t *pmd,
+			 unsigned long addr, unsigned long end, pgprot_t newprot)
+{
+	int rc = 0, i = 0;
+	mmu_update_t u[MAX_BATCHED_FULL_PTES];
+	pte_t *pte;
+	spinlock_t *ptl;
+
+	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+	do {
+		if (pte_present(*pte)) {
+			u[i].ptr = virt_to_machine(pte) | MMU_PT_UPDATE_PRESERVE_AD;
+			u[i].val = __pte_val(pte_modify(*pte, newprot));
+			if (++i == MAX_BATCHED_FULL_PTES) {
+				if ((rc = HYPERVISOR_mmu_update(
+					&u[0], i, NULL, DOMID_SELF)) != 0)
+					break;
+				i = 0;
+			}
+		}
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+	if (i)
+		rc = HYPERVISOR_mmu_update( &u[0], i, NULL, DOMID_SELF);
+	pte_unmap_unlock(pte - 1, ptl);
+	BUG_ON(rc && rc != -ENOSYS);
+	return !rc;
+}
diff -r 61c96456a3e1 mm/mprotect.c
--- a/mm/mprotect.c	Thu Dec 20 16:58:14 2007 +0000
+++ b/mm/mprotect.c	Mon Jan 07 17:48:42 2008 -0700
@@ -75,6 +75,8 @@ static inline void change_pmd_range(stru
 	do {
 		next = pmd_addr_end(addr, end);
 		if (pmd_none_or_clear_bad(pmd))
+			continue;
+		if (arch_change_pte_range(mm, pmd, addr, next, newprot))
 			continue;
 		change_pte_range(mm, pmd, addr, next, newprot);
 	} while (pmd++, addr = next, addr != end);