Re: [PATCH v4 5/7] KVM: SVM: Inject MCEs when Restricted Injection is active

Melody Wang
2026-04-28T23:00:39Z

Hi Tom,

On 4/28/26 12:24 PM, Tom Lendacky wrote:
> On 4/24/26 12:42, Melody Wang wrote:
>> When Restricted Injection is active, only #HV exceptions can be injected
>> into the SEV-SNP guest.
>>
>> Detect that, and then follow the #HV doorbell communication from the
>> GHCB specification to inject the MCEs.
>>
>> Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
>> Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
>> Signed-off-by: Melody Wang <huibo.wang@amd.com>
>> ---
>> arch/x86/include/asm/kvm-x86-ops.h | 1 +
>> arch/x86/include/asm/kvm_host.h | 1 +
>> arch/x86/kvm/svm/sev.c | 16 ++++++++++++++--
>> arch/x86/kvm/svm/svm.c | 17 +++++++++++++++++
>> arch/x86/kvm/svm/svm.h | 2 ++
>> arch/x86/kvm/vmx/main.c | 10 ++++++++++
>> arch/x86/kvm/vmx/vmx.c | 5 +++++
>> arch/x86/kvm/vmx/x86_ops.h | 1 +
>> arch/x86/kvm/x86.c | 7 +++++++
>> 9 files changed, 58 insertions(+), 2 deletions(-)
>>
>
>
>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
>> index 61e1e54deb07..2483357bdd97 100644
>> --- a/arch/x86/kvm/svm/sev.c
>> +++ b/arch/x86/kvm/svm/sev.c
>> @@ -5371,6 +5371,8 @@ static void __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
>>
>> if (type == INJECT_NMI)
>> hvdb->events.nmi = 1;
>> + else if (type == INJECT_MCE)
>> + hvdb->events.mce = 1;
>> else
>> hvdb->events.vector = vcpu->arch.interrupt.nr;
>>
>> @@ -5386,6 +5388,11 @@ bool sev_snp_queue_exception(struct kvm_vcpu *vcpu)
>> if (!sev_snp_is_rinj_active(vcpu))
>> return false;
>>
>> + if (vcpu->arch.exception.vector == MC_VECTOR) {
>> + __sev_snp_inject(INJECT_MCE, vcpu);
>> + return true;
>> + }
>> +
>> /*
>> * Restricted Injection is enabled, only #HV is supported.
>> * If the vector is not HV_VECTOR, do not inject the exception,
>> @@ -5454,7 +5461,7 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
>>
>> /*
>> * KVM only injects a single event each time (prepare_hv_injection),
>> - * so when events.nmi is true, the vector will be zero
>> + * so when events.nmi is true, the MCE and vector will be zero.
>
> This is confusing. I think you mean to say
>
> so when events.nmi or events.mce is true, the vector will be zero.
>
> correct?
>
Yes, I will update the comment.

Thanks,
Melody
> Thanks,
> Tom
>
>> */
>> if (hvdb->events.vector)
>> svm->vmcb->control.event_inj |= hvdb->events.vector |
>> @@ -5463,6 +5470,9 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
>> if (hvdb->events.nmi)
>> svm->vmcb->control.event_inj |= SVM_EVTINJ_TYPE_NMI;
>>
>> + if (hvdb->events.mce)
>> + svm->vmcb->control.event_inj |= MC_VECTOR | SVM_EVTINJ_TYPE_EXEPT;
>> +
>> hvdb->events.pending_events = 0;
>>
>> out:

--
Thanks,
Melody