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

Joerg Roedel
2010-02-18T11:39:11Z

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@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.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