linux-kernel - [PATCH 2/3] KVM: x86: let reexecute

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Date:	Tue, 20 Nov 2012 07:59:10 +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 2/3] KVM: x86: let reexecute_instruction work for tdp

Currently, reexecute_instruction refused to retry all instructions. If
nested npt is used, the emulation may be caused by shadow page, it can
be fixed by dropping the shadow page

Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
 arch/x86/kvm/x86.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7be8452..5fe72cc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4469,17 +4469,19 @@ static int handle_emulation_failure(struct kvm_vcpu *vcpu)
 	return r;
 }

-static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva)
+static bool reexecute_instruction(struct kvm_vcpu *vcpu, unsigned long cr2)
 {
-	gpa_t gpa;
+	gpa_t gpa = cr2;
 	pfn_t pfn;

-	if (tdp_enabled)
+	if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
 		return false;

-	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
-	if (gpa == UNMAPPED_GVA)
-		return true; /* let cpu generate fault */
+	if (!vcpu->arch.mmu.direct_map) {
+		gpa = kvm_mmu_gva_to_gpa_read(vcpu, cr2, NULL);
+		if (gpa == UNMAPPED_GVA)
+			return true; /* let cpu generate fault */
+	}

 	/*
 	 * if emulation was due to access to shadowed page table
-- 
1.7.7.6

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