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authorMarc Orr <marcorr@google.com>2019-04-01 23:56:00 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-04-05 21:08:30 +0200
commitc73f4c998e1fd4249b9edfa39e23f4fda2b9b041 (patch)
treeedc7161946e921978f8f5050c99f0e881de60900 /arch
parentacff78477b9b4f26ecdf65733a4ed77fe837e9dc (diff)
downloadlinux-stericsson-c73f4c998e1fd4249b9edfa39e23f4fda2b9b041.tar.gz
KVM: x86: nVMX: fix x2APIC VTPR read intercept
Referring to the "VIRTUALIZING MSR-BASED APIC ACCESSES" chapter of the SDM, when "virtualize x2APIC mode" is 1 and "APIC-register virtualization" is 0, a RDMSR of 808H should return the VTPR from the virtual APIC page. However, for nested, KVM currently fails to disable the read intercept for this MSR. This means that a RDMSR exit takes precedence over "virtualize x2APIC mode", and KVM passes through L1's TPR to L2, instead of sourcing the value from L2's virtual APIC page. This patch fixes the issue by disabling the read intercept, in VMCS02, for the VTPR when "APIC-register virtualization" is 0. The issue described above and fix prescribed here, were verified with a related patch in kvm-unit-tests titled "Test VMX's virtualize x2APIC mode w/ nested". Signed-off-by: Marc Orr <marcorr@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Fixes: c992384bde84f ("KVM: vmx: speed up MSR bitmap merge") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx/nested.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 897d70e3d291..7ec9bb1dd723 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -578,7 +578,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_TASKPRI),
- MSR_TYPE_W);
+ MSR_TYPE_R | MSR_TYPE_W);
if (nested_cpu_has_vid(vmcs12)) {
nested_vmx_disable_intercept_for_msr(