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SubjectRe: [RFC PATCH 00/62] Linux as SEV-ES Guest Support
On Tue, Feb 11, 2020 at 7:43 AM Joerg Roedel <joro@8bytes.org> wrote:
>
> On Tue, Feb 11, 2020 at 03:50:08PM +0100, Peter Zijlstra wrote:
>
> > Oh gawd; so instead of improving the whole NMI situation, AMD went and
> > made it worse still ?!?
>
> Well, depends on how you want to see it. Under SEV-ES an IRET will not
> re-open the NMI window, but the guest has to tell the hypervisor
> explicitly when it is ready to receive new NMIs via the NMI_COMPLETE
> message. NMIs stay blocked even when an exception happens in the
> handler, so this could also be seen as a (slight) improvement.
>

I don't get it. VT-x has a VMCS bit "Interruptibility
state"."Blocking by NMI" that tracks the NMI masking state. Would it
have killed AMD to solve the problem they same way to retain
architectural behavior inside a SEV-ES VM?

--Andy

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