From 90862b22bb33b14bbd30c5e9dfc41da6a7686499 Mon Sep 17 00:00:00 2001
From: kmacy <kmacy@FreeBSD.org>
Date: Sun, 8 Feb 2009 21:54:51 +0000
Subject: Don't try to directly update page tables

---
 sys/i386/xen/pmap.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 6ad67ff..4ef30f9 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -3713,14 +3713,17 @@ pmap_remove_write(vm_page_t m)
 retry:
 		oldpte = *pte;
 		if ((oldpte & PG_RW) != 0) {
+			vm_paddr_t newpte = oldpte & ~(PG_RW | PG_M);
+			
 			/*
 			 * Regardless of whether a pte is 32 or 64 bits
 			 * in size, PG_RW and PG_M are among the least
 			 * significant 32 bits.
 			 */
-			if (!atomic_cmpset_int((u_int *)pte, oldpte,
-			    oldpte & ~(PG_RW | PG_M)))
+			PT_SET_VA_MA(pte, newpte, TRUE);
+			if (*pte != newpte)
 				goto retry;
+			
 			if ((oldpte & PG_M) != 0)
 				vm_page_dirty(m);
 			pmap_invalidate_page(pmap, pv->pv_va);
-- 
cgit v1.1