linux-kernel - Re: Question about AMD SVM's virtual NMI support in Linux kernel mainline

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Message-ID: <ZOi5+rMYTVpmdQ2+@google.com>
Date:   Fri, 25 Aug 2023 07:26:02 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Santosh Shukla <santosh.shukla@....com>
Cc:     "陈培鸿(乘鸿)" 
        <chenpeihong.cph@...baba-inc.com>, mlevitsk <mlevitsk@...hat.com>,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Question about AMD SVM's virtual NMI support in Linux kernel mainline

On Fri, Aug 25, 2023, Santosh Shukla wrote:
> Hi Sean,
> >> Yes, HW does set BLOCKING_MASK when HW takes the pending vNMI event.
> > 
> > I'm not asking about the pending vNMI case, which is clearly spelled out in the
> > APM.  I'm asking about directly injecting an NMI via:
> > 
> > 	svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;
> >
> 
> Yes. This is documented in APM as well.
> https://www.amd.com/system/files/TechDocs/24593.pdf : "15.21.10 NMI Virtualization"
> 
> "
> If Event Injection is used to inject an NMI when NMI Virtualization is enabled,
> VMRUN sets V_NMI_MASK in the guest state.
> "

Awesome, thank you!