[PATCH 06/11] KVM: SVM: Fix nested msr intercept handling

[Joerg Roedel]

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@xxxxxxxxxx
Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 arch/x86/kvm/svm.c |   13 +++----------
 1 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 4becefd..f22ced1 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1456,19 +1456,13 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 {
 	u32 param = svm->vmcb->control.exit_info_1 & 1;
 	u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
-	struct page *page;
 	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, &page);
-
-	if (!msrpm)
-		goto out;
-
 	switch (msr) {
 	case 0 ... 0x1fff:
 		t0 = (msr * 2) % 8;
@@ -1489,11 +1483,10 @@ 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(page);
-
 	return ret;
 }
 
-- 
1.6.6


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