| Message ID | 20220709134230.2397-6-santosh.shukla@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Virtual NMI feature | expand |
On Sat, Jul 09, 2022, Santosh Shukla wrote: > Inject the NMI by setting V_NMI in the VMCB interrupt control. processor > will clear V_NMI to acknowledge processing has started and will keep the > V_NMI_MASK set until the processor is done with processing the NMI event. > > Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> > --- > v2: > - Added WARN_ON check for vnmi pending. > - use `get_vnmi_vmcb` to get correct vmcb so to inject vnmi. > > arch/x86/kvm/svm/svm.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 44c1f2317b45..c73a1809a7c7 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3375,12 +3375,20 @@ static void pre_svm_run(struct kvm_vcpu *vcpu) > static void svm_inject_nmi(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > + struct vmcb *vmcb = NULL; > + > + ++vcpu->stat.nmi_injections; > + if (is_vnmi_enabled(svm)) { > + vmcb = get_vnmi_vmcb(svm); > + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); Haven't read the spec, but based on the changelog I assume the flag doesn't get cleared until the NMI is fully delivered. That means this WARN will fire if a VM-Exit occurs during delivery as KVM will re-inject the event, e.g. if KVM is using shadow paging and a #PF handle by KVM occurs during delivery. > + vmcb->control.int_ctl |= V_NMI_PENDING; > + return; > + } > > svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI; > vcpu->arch.hflags |= HF_NMI_MASK; > if (!sev_es_guest(vcpu->kvm)) > svm_set_intercept(svm, INTERCEPT_IRET); > - ++vcpu->stat.nmi_injections; > } > > static void svm_inject_irq(struct kvm_vcpu *vcpu) > -- > 2.25.1 >
On Wed, Jul 20, 2022 at 2:41 PM Sean Christopherson <seanjc@google.com> wrote: > > On Sat, Jul 09, 2022, Santosh Shukla wrote: > > Inject the NMI by setting V_NMI in the VMCB interrupt control. processor > > will clear V_NMI to acknowledge processing has started and will keep the > > V_NMI_MASK set until the processor is done with processing the NMI event. > > > > Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> > > --- > > v2: > > - Added WARN_ON check for vnmi pending. > > - use `get_vnmi_vmcb` to get correct vmcb so to inject vnmi. > > > > arch/x86/kvm/svm/svm.c | 10 +++++++++- > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > index 44c1f2317b45..c73a1809a7c7 100644 > > --- a/arch/x86/kvm/svm/svm.c > > +++ b/arch/x86/kvm/svm/svm.c > > @@ -3375,12 +3375,20 @@ static void pre_svm_run(struct kvm_vcpu *vcpu) > > static void svm_inject_nmi(struct kvm_vcpu *vcpu) > > { > > struct vcpu_svm *svm = to_svm(vcpu); > > + struct vmcb *vmcb = NULL; > > + > > + ++vcpu->stat.nmi_injections; > > + if (is_vnmi_enabled(svm)) { > > + vmcb = get_vnmi_vmcb(svm); > > + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); > > Haven't read the spec, but based on the changelog I assume the flag doesn't get > cleared until the NMI is fully delivered. Ooh! Is there a spec to read now?!?
On Wed, Jul 20, 2022, Jim Mattson wrote: > On Wed, Jul 20, 2022 at 2:41 PM Sean Christopherson <seanjc@google.com> wrote: > > > > On Sat, Jul 09, 2022, Santosh Shukla wrote: > > > Inject the NMI by setting V_NMI in the VMCB interrupt control. processor > > > will clear V_NMI to acknowledge processing has started and will keep the > > > V_NMI_MASK set until the processor is done with processing the NMI event. > > > > > > Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> > > > --- > > > v2: > > > - Added WARN_ON check for vnmi pending. > > > - use `get_vnmi_vmcb` to get correct vmcb so to inject vnmi. > > > > > > arch/x86/kvm/svm/svm.c | 10 +++++++++- > > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > > index 44c1f2317b45..c73a1809a7c7 100644 > > > --- a/arch/x86/kvm/svm/svm.c > > > +++ b/arch/x86/kvm/svm/svm.c > > > @@ -3375,12 +3375,20 @@ static void pre_svm_run(struct kvm_vcpu *vcpu) > > > static void svm_inject_nmi(struct kvm_vcpu *vcpu) > > > { > > > struct vcpu_svm *svm = to_svm(vcpu); > > > + struct vmcb *vmcb = NULL; > > > + > > > + ++vcpu->stat.nmi_injections; > > > + if (is_vnmi_enabled(svm)) { > > > + vmcb = get_vnmi_vmcb(svm); > > > + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); > > > > Haven't read the spec, but based on the changelog I assume the flag doesn't get > > cleared until the NMI is fully delivered. > > Ooh! Is there a spec to read now?!? Apparently not. I just assumed there's a spec, but I haven't found one.
Hi Sean, On 7/21/2022 3:11 AM, Sean Christopherson wrote: > On Sat, Jul 09, 2022, Santosh Shukla wrote: >> Inject the NMI by setting V_NMI in the VMCB interrupt control. processor >> will clear V_NMI to acknowledge processing has started and will keep the >> V_NMI_MASK set until the processor is done with processing the NMI event. >> >> Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> >> --- >> v2: >> - Added WARN_ON check for vnmi pending. >> - use `get_vnmi_vmcb` to get correct vmcb so to inject vnmi. >> >> arch/x86/kvm/svm/svm.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c >> index 44c1f2317b45..c73a1809a7c7 100644 >> --- a/arch/x86/kvm/svm/svm.c >> +++ b/arch/x86/kvm/svm/svm.c >> @@ -3375,12 +3375,20 @@ static void pre_svm_run(struct kvm_vcpu *vcpu) >> static void svm_inject_nmi(struct kvm_vcpu *vcpu) >> { >> struct vcpu_svm *svm = to_svm(vcpu); >> + struct vmcb *vmcb = NULL; >> + >> + ++vcpu->stat.nmi_injections; >> + if (is_vnmi_enabled(svm)) { >> + vmcb = get_vnmi_vmcb(svm); >> + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); > > Haven't read the spec, but based on the changelog I assume the flag doesn't get > cleared until the NMI is fully delivered. That means this WARN will fire if a > VM-Exit occurs during delivery as KVM will re-inject the event, e.g. if KVM is > using shadow paging and a #PF handle by KVM occurs during delivery. > Right,. For the above scenario i.e.. if VMEXIT happens during delivery of virtual NMI then EXITINTINFO will be set accordingly and V_NMI_MASK is saved as 0. hypervisor will re-inject event in next VMRUN. I just wanted to track above scenario,. I will replace it with pr_debug(). Thanks, Santosh >> + vmcb->control.int_ctl |= V_NMI_PENDING; >> + return; >> + } >> >> svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI; >> vcpu->arch.hflags |= HF_NMI_MASK; >> if (!sev_es_guest(vcpu->kvm)) >> svm_set_intercept(svm, INTERCEPT_IRET); >> - ++vcpu->stat.nmi_injections; >> } >> >> static void svm_inject_irq(struct kvm_vcpu *vcpu) >> -- >> 2.25.1 >>
On Fri, Jul 29, 2022, Shukla, Santosh wrote: > Hi Sean, > > On 7/21/2022 3:11 AM, Sean Christopherson wrote: > > On Sat, Jul 09, 2022, Santosh Shukla wrote: > >> + ++vcpu->stat.nmi_injections; > >> + if (is_vnmi_enabled(svm)) { > >> + vmcb = get_vnmi_vmcb(svm); > >> + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); > > > > Haven't read the spec, but based on the changelog I assume the flag doesn't get > > cleared until the NMI is fully delivered. That means this WARN will fire if a > > VM-Exit occurs during delivery as KVM will re-inject the event, e.g. if KVM is > > using shadow paging and a #PF handle by KVM occurs during delivery. > > > > Right,. > > > For the above scenario i.e.. if VMEXIT happens during delivery of virtual NMI > then EXITINTINFO will be set accordingly and V_NMI_MASK is saved as 0. > hypervisor will re-inject event in next VMRUN. > > I just wanted to track above scenario,. I will replace it with pr_debug(). No, this is normal (albeit uncommon) behavior, don't print anything. Even if it weren't normal behavior, pr_debug() is usually the wrong choice in KVM.
On 7/29/2022 7:23 PM, Sean Christopherson wrote: > On Fri, Jul 29, 2022, Shukla, Santosh wrote: >> Hi Sean, >> >> On 7/21/2022 3:11 AM, Sean Christopherson wrote: >>> On Sat, Jul 09, 2022, Santosh Shukla wrote: >>>> + ++vcpu->stat.nmi_injections; >>>> + if (is_vnmi_enabled(svm)) { >>>> + vmcb = get_vnmi_vmcb(svm); >>>> + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); >>> >>> Haven't read the spec, but based on the changelog I assume the flag doesn't get >>> cleared until the NMI is fully delivered. That means this WARN will fire if a >>> VM-Exit occurs during delivery as KVM will re-inject the event, e.g. if KVM is >>> using shadow paging and a #PF handle by KVM occurs during delivery. >>> >> >> Right,. >> >> >> For the above scenario i.e.. if VMEXIT happens during delivery of virtual NMI >> then EXITINTINFO will be set accordingly and V_NMI_MASK is saved as 0. >> hypervisor will re-inject event in next VMRUN. >> >> I just wanted to track above scenario,. I will replace it with pr_debug(). > > No, this is normal (albeit uncommon) behavior, don't print anything. Even if it Ok. Thanks, Santosh > weren't normal behavior, pr_debug() is usually the wrong choice in KVM.
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 44c1f2317b45..c73a1809a7c7 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3375,12 +3375,20 @@ static void pre_svm_run(struct kvm_vcpu *vcpu) static void svm_inject_nmi(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + struct vmcb *vmcb = NULL; + + ++vcpu->stat.nmi_injections; + if (is_vnmi_enabled(svm)) { + vmcb = get_vnmi_vmcb(svm); + WARN_ON(vmcb->control.int_ctl & V_NMI_PENDING); + vmcb->control.int_ctl |= V_NMI_PENDING; + return; + } svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI; vcpu->arch.hflags |= HF_NMI_MASK; if (!sev_es_guest(vcpu->kvm)) svm_set_intercept(svm, INTERCEPT_IRET); - ++vcpu->stat.nmi_injections; } static void svm_inject_irq(struct kvm_vcpu *vcpu)
Inject the NMI by setting V_NMI in the VMCB interrupt control. processor will clear V_NMI to acknowledge processing has started and will keep the V_NMI_MASK set until the processor is done with processing the NMI event. Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> --- v2: - Added WARN_ON check for vnmi pending. - use `get_vnmi_vmcb` to get correct vmcb so to inject vnmi. arch/x86/kvm/svm/svm.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)