From 091abbf578f926e763adc0f577baeb7f405b4bdc Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Thu, 19 May 2022 05:27:09 -0500 Subject: [PATCH] KVM: x86: nSVM: optimize svm_set_x2apic_msr_interception - Avoid toggling the x2apic msr interception if it is already up to date. - Avoid touching L0 msr bitmap when AVIC is inhibited on entry to the guest mode, because in this case the guest usually uses its own msr bitmap. Later on VM exit, the 1st optimization will allow KVM to skip touching the L0 msr bitmap as well. Reviewed-by: Suravee Suthikulpanit Tested-by: Suravee Suthikulpanit Signed-off-by: Maxim Levitsky Message-Id: <20220519102709.24125-18-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 8 ++++++++ arch/x86/kvm/svm/svm.c | 7 +++++++ arch/x86/kvm/svm/svm.h | 2 ++ 3 files changed, 17 insertions(+) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index f18c852b69007..6919dee69f182 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -100,6 +100,14 @@ static void avic_deactivate_vmcb(struct vcpu_svm *svm) vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK); vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK; + /* + * If running nested and the guest uses its own MSR bitmap, there + * is no need to update L0's msr bitmap + */ + if (is_guest_mode(&svm->vcpu) && + vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)) + return; + /* Enabling MSR intercept for x2APIC registers */ svm_set_x2apic_msr_interception(svm, true); } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index bb0457c1e41ca..37ce061dfc767 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -809,6 +809,9 @@ void svm_set_x2apic_msr_interception(struct vcpu_svm *svm, bool intercept) { int i; + if (intercept == svm->x2avic_msrs_intercepted) + return; + if (avic_mode != AVIC_MODE_X2 || !apic_x2apic_mode(svm->vcpu.arch.apic)) return; @@ -822,6 +825,8 @@ void svm_set_x2apic_msr_interception(struct vcpu_svm *svm, bool intercept) set_msr_interception(&svm->vcpu, svm->msrpm, index, !intercept, !intercept); } + + svm->x2avic_msrs_intercepted = intercept; } void svm_vcpu_free_msrpm(u32 *msrpm) @@ -1393,6 +1398,8 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu) goto error_free_vmsa_page; } + svm->x2avic_msrs_intercepted = true; + svm->vmcb01.ptr = page_address(vmcb01_page); svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT); svm_switch_vmcb(svm, &svm->vmcb01); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index ccaae7d160cd8..558ca1296d368 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -276,6 +276,8 @@ struct vcpu_svm { struct vcpu_sev_es_state sev_es; bool guest_state_loaded; + + bool x2avic_msrs_intercepted; }; struct svm_cpu_data { -- 2.30.2