linux-kernel - [PATCH v3 1/7] KVM: MMU: fix release noslot pfn

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Date:	Fri, 21 Sep 2012 14:57:19 +0800
From:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
CC:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH v3 1/7] KVM: MMU: fix release noslot pfn

We can not directly call kvm_release_pfn_clean to release the pfn
since we can meet noslot pfn which is used to cache mmio info into
spte

Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
 arch/x86/kvm/mmu.c         |    6 ++++--
 arch/x86/kvm/paging_tmpl.h |    6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index aa0b469..0f56169 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2877,7 +2877,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,

 out_unlock:
 	spin_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(pfn);
+	if (likely(!is_noslot_pfn(pfn)))
+		kvm_release_pfn_clean(pfn);
 	return 0;
 }

@@ -3345,7 +3346,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,

 out_unlock:
 	spin_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(pfn);
+	if (likely(!is_noslot_pfn(pfn)))
+		kvm_release_pfn_clean(pfn);
 	return 0;
 }

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index bf8c42b..9ce6bc0 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -544,7 +544,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 out_gpte_changed:
 	if (sp)
 		kvm_mmu_put_page(sp, it.sptep);
-	kvm_release_pfn_clean(pfn);
+	if (likely(!is_noslot_pfn(pfn)))
+		kvm_release_pfn_clean(pfn);
 	return NULL;
 }

@@ -645,7 +646,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,

 out_unlock:
 	spin_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(pfn);
+	if (likely(!is_noslot_pfn(pfn)))
+		kvm_release_pfn_clean(pfn);
 	return 0;
 }

-- 
1.7.7.6

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