linux-kernel - [PATCH v2 02/22] KVM: MMU: do not update slot bitmap if spte is nonpresent

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Message-ID: <4E01FC1B.6070701@cn.fujitsu.com>
Date:	Wed, 22 Jun 2011 22:28:43 +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 02/22] KVM: MMU: do not update slot bitmap if spte is nonpresent

Set slot bitmap only if the spte is present

Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
 arch/x86/kvm/mmu.c |   15 +++++++--------
 1 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f474e93..8316c2d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -743,9 +743,6 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
 	struct kvm_mmu_page *sp;
 	unsigned long *rmapp;
 
-	if (!is_rmap_spte(*spte))
-		return 0;
-
 	sp = page_header(__pa(spte));
 	kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
 	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
@@ -2087,11 +2084,13 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 	if (!was_rmapped && is_large_pte(*sptep))
 		++vcpu->kvm->stat.lpages;
 
-	page_header_update_slot(vcpu->kvm, sptep, gfn);
-	if (!was_rmapped) {
-		rmap_count = rmap_add(vcpu, sptep, gfn);
-		if (rmap_count > RMAP_RECYCLE_THRESHOLD)
-			rmap_recycle(vcpu, sptep, gfn);
+	if (is_shadow_present_pte(*sptep)) {
+		page_header_update_slot(vcpu->kvm, sptep, gfn);
+		if (!was_rmapped) {
+			rmap_count = rmap_add(vcpu, sptep, gfn);
+			if (rmap_count > RMAP_RECYCLE_THRESHOLD)
+				rmap_recycle(vcpu, sptep, gfn);
+		}
 	}
 	kvm_release_pfn_clean(pfn);
 	if (speculative) {
-- 
1.7.5.4

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