Allows L1 to use vNMI to accelerate its injection of NMI to L2 by passing through vNMI int_ctl bits from vmcb12 to/from vmcb02. In case of L1 and L2 both using VNMI- Copy VNMI bits from vmcb12 to vmcb02 during entry and vice-versa during exit. And in case of L1 uses VNMI and L2 doesn't- Copy VNMI bits from vmcb01 to vmcb02 during entry and vice-versa during exit. Tested with the KVM-unit-test and Nested Guest scenario. Co-developed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Signed-off-by: Santosh Shukla <santosh.shukla@xxxxxxx> --- v3: - Fix identiation and style issue. - Fix SOB - Removed `svm->nmi_masked` var use for nested svm case. - Reworded the commit description. https://lore.kernel.org/all/Y9m15P8xQ2dxvIzd@xxxxxxxxxx/ arch/x86/kvm/svm/nested.c | 33 +++++++++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 5 +++++ arch/x86/kvm/svm/svm.h | 6 ++++++ 3 files changed, 44 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 74e9e9e76d77..b018fe2fdf88 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -281,6 +281,11 @@ static bool __nested_vmcb_check_controls(struct kvm_vcpu *vcpu, if (CC(!nested_svm_check_tlb_ctl(vcpu, control->tlb_ctl))) return false; + if (CC((control->int_ctl & V_NMI_ENABLE_MASK) && + !vmcb12_is_intercept(control, INTERCEPT_NMI))) { + return false; + } + return true; } @@ -436,6 +441,9 @@ void nested_sync_control_from_vmcb02(struct vcpu_svm *svm) if (nested_vgif_enabled(svm)) mask |= V_GIF_MASK; + if (nested_vnmi_enabled(svm)) + mask |= V_NMI_BLOCKING_MASK | V_NMI_PENDING_MASK; + svm->nested.ctl.int_ctl &= ~mask; svm->nested.ctl.int_ctl |= svm->vmcb->control.int_ctl & mask; } @@ -655,6 +663,17 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm, else int_ctl_vmcb01_bits |= (V_GIF_MASK | V_GIF_ENABLE_MASK); + if (vnmi) { + if (vmcb01->control.int_ctl & V_NMI_PENDING_MASK) { + svm->vcpu.arch.nmi_pending++; + kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); + } + if (nested_vnmi_enabled(svm)) + int_ctl_vmcb12_bits |= (V_NMI_PENDING_MASK | + V_NMI_ENABLE_MASK | + V_NMI_BLOCKING_MASK); + } + /* Copied from vmcb01. msrpm_base can be overwritten later. */ vmcb02->control.nested_ctl = vmcb01->control.nested_ctl; vmcb02->control.iopm_base_pa = vmcb01->control.iopm_base_pa; @@ -1058,6 +1077,20 @@ int nested_svm_vmexit(struct vcpu_svm *svm) svm_update_lbrv(vcpu); } + if (vnmi) { + if (vmcb02->control.int_ctl & V_NMI_BLOCKING_MASK) + vmcb01->control.int_ctl |= V_NMI_BLOCKING_MASK; + else + vmcb01->control.int_ctl &= ~V_NMI_BLOCKING_MASK; + + if (vcpu->arch.nmi_pending) { + vcpu->arch.nmi_pending--; + vmcb01->control.int_ctl |= V_NMI_PENDING_MASK; + } else + vmcb01->control.int_ctl &= ~V_NMI_PENDING_MASK; + + } + /* * On vmexit the GIF is set to false and * no event can be injected in L1. diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 84d9d2566629..08b7856e2da2 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4226,6 +4226,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) svm->vgif_enabled = vgif && guest_cpuid_has(vcpu, X86_FEATURE_VGIF); + svm->vnmi_enabled = vnmi && guest_cpuid_has(vcpu, X86_FEATURE_AMD_VNMI); + svm_recalc_instruction_intercepts(vcpu, svm); /* For sev guests, the memory encryption bit is not reserved in CR3. */ @@ -4981,6 +4983,9 @@ static __init void svm_set_cpu_caps(void) if (vgif) kvm_cpu_cap_set(X86_FEATURE_VGIF); + if (vnmi) + kvm_cpu_cap_set(X86_FEATURE_AMD_VNMI); + /* 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 fb48c347bbe0..e229eadbf1ce 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -266,6 +266,7 @@ struct vcpu_svm { bool pause_filter_enabled : 1; bool pause_threshold_enabled : 1; bool vgif_enabled : 1; + bool vnmi_enabled : 1; u32 ldr_reg; u32 dfr_reg; @@ -540,6 +541,11 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm) return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE; } +static inline bool nested_vnmi_enabled(struct vcpu_svm *svm) +{ + return svm->vnmi_enabled && (svm->nested.ctl.int_ctl & V_NMI_ENABLE_MASK); +} + static inline bool is_x2apic_msrpm_offset(u32 offset) { /* 4 msrs per u8, and 4 u8 in u32 */ -- 2.25.1
