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

Tom Lendacky
2026-04-28T19:24:51Z

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?

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;
>