Re: [PATCH 5/7] KVM: SVM: Add VNMI support in inject_nmi
From: Maxim Levitsky
Date: Tue Jun 07 2022 - 09:14:43 EST
On Thu, 2022-06-02 at 19:56 +0530, 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@xxxxxxx>
> ---
> arch/x86/kvm/svm/svm.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index a405e414cae4..200f979169e0 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3385,11 +3385,16 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
>
> + ++vcpu->stat.nmi_injections;
> + if (is_vnmi_enabled(svm->vmcb)) {
> + svm->vmcb->control.int_ctl |= V_NMI_PENDING;
> + return;
> + }
Here I would advice to have a warning to check if vNMI is already pending.
Also we need to check what happens if we make vNMI pending and get #SMI,
while in #NMI handler, or if #NMI is blocked due to interrupt window.
Best regards,
Maxim Levitsky
> +
> 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)