linux-kernel - [PATCH v2 01/22] KVM: MMU: fix walking shadow page table

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Message-ID: <4E01FBF4.9070004@cn.fujitsu.com>
Date:	Wed, 22 Jun 2011 22:28:04 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH v2 01/22] KVM: MMU: fix walking shadow page table

Properly check the last mapping, and do not walk to the next level if last spte
is met

Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
 arch/x86/kvm/mmu.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 9c629b5..f474e93 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1517,10 +1517,6 @@ static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
 	if (iterator->level < PT_PAGE_TABLE_LEVEL)
 		return false;
 
-	if (iterator->level == PT_PAGE_TABLE_LEVEL)
-		if (is_large_pte(*iterator->sptep))
-			return false;
-
 	iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
 	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
 	return true;
@@ -1528,6 +1524,11 @@ static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
 
 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
 {
+	if (is_last_spte(*iterator->sptep, iterator->level)) {
+		iterator->level = 0;
+		return;
+	}
+
 	iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
 	--iterator->level;
 }
-- 
1.7.5.4

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