Re: [PATCH v2 2/2] KVM: VMX: Invoke NMI handler via indirect call instead of INTn

From: Andi Kleen
Date: Mon Apr 26 2021 - 10:51:09 EST


> > The original code "int $2" can provide the needed CPU-hidden-NMI-masked
> > when entering #NMI, but I doubt it about this change.
>
> How would "int $2" block NMIs? The hidden effect of this change (and I
> should have reviewed better the effect on the NMI entry code) is that the
> call will not use the IST anymore.

My understanding is that int $2 does not block NMIs.

So reentries might have been possible.

-Andi