From: Zhao Jin <cronozhj@gmail.com>
Date: Mon, 19 Sep 2011 04:19:51 +0000 (+0800)
Subject: KVM: MMU: fix incorrect return of spte
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=41bc3186b3c92a4ca05e2aa14bb6272fb491e679;p=linux-beck.git

KVM: MMU: fix incorrect return of spte

__update_clear_spte_slow should return original spte while the
current code returns low half of original spte combined with high
half of new spte.

Signed-off-by: Zhao Jin <cronozhj@gmail.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 1c5b69373a00..8e8da7960dbe 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -400,7 +400,8 @@ static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
 
 	/* xchg acts as a barrier before the setting of the high bits */
 	orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
-	orig.spte_high = ssptep->spte_high = sspte.spte_high;
+	orig.spte_high = ssptep->spte_high;
+	ssptep->spte_high = sspte.spte_high;
 	count_spte_clear(sptep, spte);
 
 	return orig.spte;