From 74fd41ed16fd71725e69e2cb90b755505326c2e6 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Tue, 22 Mar 2022 19:40:47 +0200 Subject: KVM: x86: nSVM: support PAUSE filtering when L0 doesn't intercept PAUSE Expose the pause filtering and threshold in the guest CPUID and support PAUSE filtering when possible: - If the L0 doesn't intercept PAUSE (cpu_pm=on), then allow L1 to have full control over PAUSE filtering. - if the L1 doesn't intercept PAUSE, use host values and update the adaptive count/threshold even when running nested. - Otherwise always exit to L1; it is not really possible to merge the fields correctly. It is expected that in this case, userspace will not enable this feature in the guest CPUID, to avoid having the guest update both fields pointlessly. Signed-off-by: Maxim Levitsky Message-Id: <20220322174050.241850-4-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/nested.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'arch/x86/kvm/svm/nested.c') diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index f1332d802ec8..fe0011771b10 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -668,6 +668,29 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) if (!nested_vmcb_needs_vls_intercept(svm)) vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK; + if (kvm_pause_in_guest(svm->vcpu.kvm)) { + /* use guest values since host doesn't use them */ + vmcb02->control.pause_filter_count = + svm->pause_filter_enabled ? + svm->nested.ctl.pause_filter_count : 0; + + vmcb02->control.pause_filter_thresh = + svm->pause_threshold_enabled ? + svm->nested.ctl.pause_filter_thresh : 0; + + } else if (!vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_PAUSE)) { + /* use host values when guest doesn't use them */ + vmcb02->control.pause_filter_count = vmcb01->control.pause_filter_count; + vmcb02->control.pause_filter_thresh = vmcb01->control.pause_filter_thresh; + } else { + /* + * Intercept every PAUSE otherwise and + * ignore both host and guest values + */ + vmcb02->control.pause_filter_count = 0; + vmcb02->control.pause_filter_thresh = 0; + } + nested_svm_transition_tlb_flush(vcpu); /* Enter Guest-Mode */ @@ -928,6 +951,9 @@ int nested_svm_vmexit(struct vcpu_svm *svm) vmcb12->control.event_inj = svm->nested.ctl.event_inj; vmcb12->control.event_inj_err = svm->nested.ctl.event_inj_err; + if (!kvm_pause_in_guest(vcpu->kvm) && vmcb02->control.pause_filter_count) + vmcb01->control.pause_filter_count = vmcb02->control.pause_filter_count; + nested_svm_copy_common_state(svm->nested.vmcb02.ptr, svm->vmcb01.ptr); svm_switch_vmcb(svm, &svm->vmcb01); -- cgit v1.2.3-71-gd317