On Mon, Apr 6, 2026 at 4:47 PM Sean Christopherson <[email protected]> wrote: > > 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); > LOL! Aren't you the one who keeps complaining that my indentation doesn't line up? Are you schizophrenic?
> 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; Wow. I really have no idea how to predict what you're going to want the code to look like. How is this better than the original?!? > > > + 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 > >
