This avoids basing decisions on uninitialized variables, potentially
leaking kernel data to the L1 guest.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2633199..81a25de 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5991,7 +5991,8 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu,
/* Then read the msr_index'th bit from this bitmap: */
if (msr_index < 1024*8) {
unsigned char b;
- kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1);
+ if (kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1))
+ return 1;
return 1 & (b >> (msr_index & 7));
} else
return 1; /* let L1 handle the wrong parameter */
--
1.7.3.4
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