linux-kernel - [PATCH 06/10] KVM: SVM: Fix nested msr intercept handling

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Message-ID: <1266493115-28386-7-git-send-email-joerg.roedel@amd.com>
Date:	Thu, 18 Feb 2010 12:38:31 +0100
From:	Joerg Roedel <joerg.roedel@....com>
To:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
CC:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Joerg Roedel <joerg.roedel@....com>, stable@...nel.org
Subject: [PATCH 06/10] KVM: SVM: Fix nested msr intercept handling

The nested_svm_exit_handled_msr() function maps only one
page of the guests msr permission bitmap. This patch changes
the code to use kvm_read_guest to fix the bug.

Cc: stable@...nel.org
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 arch/x86/kvm/svm.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3f59cbd..cbf798f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1457,16 +1457,11 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 	u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
 	bool ret = false;
 	u32 t0, t1;
-	u8 *msrpm;
+	u8 val;
 
 	if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
 		return false;
 
-	msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm);
-
-	if (!msrpm)
-		goto out;
-
 	switch (msr) {
 	case 0 ... 0x1fff:
 		t0 = (msr * 2) % 8;
@@ -1487,11 +1482,10 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 		goto out;
 	}
 
-	ret = msrpm[t1] & ((1 << param) << t0);
+	if (!kvm_read_guest(svm->vcpu.kvm, svm->nested.vmcb_msrpm + t1, &val, 1))
+		ret = val & ((1 << param) << t0);
 
 out:
-	nested_svm_unmap(msrpm);
-
 	return ret;
 }
 
-- 
1.6.6


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