According to the APM volume 2, section 15.25.2: "Replicated State," While nested paging is enabled, all (guest) references to the state of the paging registers by x86 code (MOV to/from CRn, etc.) read and write the guest copy of the registers. The PAT MSR is explicitly enumerated as a "paging register" in that section of the APM. Implement the architected behavior by redirecting PAT MSR accesses from vcpu->arch.pat to svm->vmcb->save.g_pat when L2 is active and nested paging is enabled in vmcb12. Note that the change in KVM_{GET,SET}_MSRS semantics breaks serialization. Trigger a fixup in svm_set_nested_state() by setting the VALID_GPAT flag in the SVM nested state header. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Signed-off-by: Jim Mattson --- arch/x86/kvm/svm/nested.c | 1 + arch/x86/kvm/svm/svm.c | 25 +++++++++++++++++-------- 2 files changed, 18 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index ad11b11f482e..c68511948501 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1728,6 +1728,7 @@ static int svm_get_nested_state(struct kvm_vcpu *vcpu, /* First fill in the header and copy it out. */ if (is_guest_mode(vcpu)) { kvm_state.hdr.svm.vmcb_pa = svm->nested.vmcb12_gpa; + kvm_state.hdr.svm.flags = KVM_STATE_SVM_VALID_GPAT; kvm_state.size += KVM_STATE_NESTED_SVM_VMCB_SIZE; kvm_state.flags |= KVM_STATE_NESTED_GUEST_MODE; diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b4e5a0684f57..7e192fd5fb7f 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2675,6 +2675,12 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; msr_info->data = svm->tsc_ratio_msr; break; + case MSR_IA32_CR_PAT: + if (!(is_guest_mode(vcpu) && nested_npt_enabled(svm))) + msr_info->data = vcpu->arch.pat; + else + msr_info->data = svm->vmcb->save.g_pat; + break; case MSR_STAR: msr_info->data = svm->vmcb01.ptr->save.star; break; @@ -2864,14 +2870,17 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) break; case MSR_IA32_CR_PAT: - ret = kvm_set_msr_common(vcpu, msr); - if (ret) - break; - - svm->vmcb01.ptr->save.g_pat = data; - if (is_guest_mode(vcpu)) - nested_vmcb02_compute_g_pat(svm); - vmcb_mark_dirty(svm->vmcb, VMCB_NPT); + if (!kvm_pat_valid(data)) + return 1; + if (!(is_guest_mode(vcpu) && nested_npt_enabled(svm))) { + vcpu->arch.pat = data; + svm->vmcb01.ptr->save.g_pat = data; + vmcb_mark_dirty(svm->vmcb01.ptr, VMCB_NPT); + } + if (is_guest_mode(vcpu)) { + svm->vmcb->save.g_pat = data; + vmcb_mark_dirty(svm->vmcb, VMCB_NPT); + } break; case MSR_IA32_SPEC_CTRL: if (!msr->host_initiated && -- 2.51.2.1041.gc1ab5b90ca-goog