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Peter Anvin" , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Yosry Ahmed Content-Type: text/plain; charset="us-ascii" On Fri, Mar 27, 2026, Jim Mattson wrote: > @@ -1918,6 +1921,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > struct vmcb_save_area_cached save_cached; > struct vmcb_ctrl_area_cached ctl_cached; > unsigned long cr0; > + bool use_separate_l2_pat; Land this above "cr0" to preserve the inverted fir tree. > int ret; > > BUILD_BUG_ON(sizeof(struct vmcb_control_area) + sizeof(struct vmcb_save_area) > > @@ -1993,6 +1997,18 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > !nested_vmcb_check_save(vcpu, &save_cached, false)) > goto out_free; > > + /* > + * Validate gPAT when the shared PAT quirk is disabled (i.e. L2 > + * has its own gPAT). This is done separately from the > + * vmcb_save_area_cached validation above, because gPAT is L2 > + * state, but the vmcb_save_area_cached is populated with L1 state. > + */ > + use_separate_l2_pat = > + (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP) && > + !kvm_check_has_quirk(vcpu->kvm, > + KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT); I vote for either: use_separate_l2_pat = (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP) && !kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT); or use_separate_l2_pat = (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP); if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT)) use_separate_l2_pat = false; > + if (use_separate_l2_pat && !kvm_pat_valid(kvm_state->hdr.svm.gpat)) > + goto out_free; > > /* > * All checks done, we can enter guest mode. Userspace provides > @@ -2017,6 +2033,10 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > nested_copy_vmcb_control_to_cache(svm, ctl); > > svm_switch_vmcb(svm, &svm->nested.vmcb02); > + > + if (use_separate_l2_pat) > + vmcb_set_gpat(svm->vmcb, kvm_state->hdr.svm.gpat); > + > nested_vmcb02_prepare_control(svm); > > /* > -- > 2.53.0.1018.g2bb0e51243-goog >