Expose the Bus Lock Threshold in the guest CPUID and support its functionality in nested guest.
Ensure proper restoration and saving of the bus_lock_counter at VM Entry and VM Exit respectively in nested guest scenarios.
Case 1: L0 supports buslock exit and L1 does not: use buslock counter from L0 and exits happen to L0 VMM.
Case 2: Both L0 and L1 supports buslock exit: use L1 buslock counter value and exits happen to L1 VMM.
Signed-off-by: Manali Shukla manali.shukla@amd.com --- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/svm/nested.c | 25 +++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 5 +++++ arch/x86/kvm/svm/svm.h | 1 + 4 files changed, 32 insertions(+)
diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h index ad463b1ed4e4..0982eb107f0b 100644 --- a/arch/x86/kvm/governed_features.h +++ b/arch/x86/kvm/governed_features.h @@ -17,6 +17,7 @@ KVM_GOVERNED_X86_FEATURE(PFTHRESHOLD) KVM_GOVERNED_X86_FEATURE(VGIF) KVM_GOVERNED_X86_FEATURE(VNMI) KVM_GOVERNED_X86_FEATURE(LAM) +KVM_GOVERNED_X86_FEATURE(BUS_LOCK_THRESHOLD)
#undef KVM_GOVERNED_X86_FEATURE #undef KVM_GOVERNED_FEATURE diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 6f704c1037e5..d09434225e4d 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -363,6 +363,7 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, to->virt_ext = from->virt_ext; to->pause_filter_count = from->pause_filter_count; to->pause_filter_thresh = from->pause_filter_thresh; + to->bus_lock_counter = from->bus_lock_counter;
/* Copy asid here because nested_vmcb_check_controls will check it. */ to->asid = from->asid; @@ -758,6 +759,16 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm, } }
+ /* + * If guest intercepts BUSLOCK, use guest's bus_lock_counter value, + * otherwise use host bus_lock_counter value. + */ + if (guest_can_use(vcpu, X86_FEATURE_BUS_LOCK_THRESHOLD) && + vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_BUSLOCK)) + vmcb02->control.bus_lock_counter = svm->nested.ctl.bus_lock_counter; + else + vmcb02->control.bus_lock_counter = vmcb01->control.bus_lock_counter; + nested_svm_transition_tlb_flush(vcpu);
/* Enter Guest-Mode */ @@ -1035,6 +1046,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
}
+ if (guest_can_use(vcpu, X86_FEATURE_BUS_LOCK_THRESHOLD) && + vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_BUSLOCK)) + vmcb12->control.bus_lock_counter = vmcb02->control.bus_lock_counter; + else + vmcb01->control.bus_lock_counter = vmcb02->control.bus_lock_counter; + nested_svm_copy_common_state(svm->nested.vmcb02.ptr, svm->vmcb01.ptr);
svm_switch_vmcb(svm, &svm->vmcb01); @@ -1333,6 +1350,13 @@ static int nested_svm_intercept(struct vcpu_svm *svm) vmexit = NESTED_EXIT_DONE; break; } + case SVM_EXIT_BUS_LOCK: { + if (!(vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_BUSLOCK))) + vmexit = NESTED_EXIT_HOST; + else + vmexit = NESTED_EXIT_DONE; + break; + } default: { if (vmcb12_is_intercept(&svm->nested.ctl, exit_code)) vmexit = NESTED_EXIT_DONE; @@ -1572,6 +1596,7 @@ static void nested_copy_vmcb_cache_to_control(struct vmcb_control_area *dst, dst->virt_ext = from->virt_ext; dst->pause_filter_count = from->pause_filter_count; dst->pause_filter_thresh = from->pause_filter_thresh; + dst->bus_lock_counter = from->bus_lock_counter; /* 'clean' and 'hv_enlightenments' are not changed by KVM */ }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9f1d51384eac..bb2437a7694c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4373,6 +4373,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) set_msr_interception(vcpu, svm->msrpm, MSR_IA32_FLUSH_CMD, 0, !!guest_cpuid_has(vcpu, X86_FEATURE_FLUSH_L1D));
+ kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_BUS_LOCK_THRESHOLD); + if (cpu_feature_enabled(X86_FEATURE_BUS_LOCK_THRESHOLD) && vcpu->kvm->arch.bus_lock_detection_enabled) { svm_set_intercept(svm, INTERCEPT_BUSLOCK); @@ -5183,6 +5185,9 @@ static __init void svm_set_cpu_caps(void) if (vnmi) kvm_cpu_cap_set(X86_FEATURE_VNMI);
+ if (cpu_feature_enabled(X86_FEATURE_BUS_LOCK_THRESHOLD)) + kvm_cpu_cap_set(X86_FEATURE_BUS_LOCK_THRESHOLD); + /* Nested VM can receive #VMEXIT instead of triggering #GP */ kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK); } diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 8983eabf8f84..f49ea38187ba 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -150,6 +150,7 @@ struct vmcb_ctrl_area_cached { u64 nested_cr3; u64 virt_ext; u32 clean; + u16 bus_lock_counter; union { #if IS_ENABLED(CONFIG_HYPERV) || IS_ENABLED(CONFIG_KVM_HYPERV) struct hv_vmcb_enlightenments hv_enlightenments;