Re: [PATCH 12/13] KVM: x86: Replace late check_nested_events() hack with more precise fix

From: Paolo Bonzini
Date: Wed Apr 29 2020 - 12:58:53 EST


On 29/04/20 18:45, Sean Christopherson wrote:
>
> Can you just drop 9/13, "Prioritize SMI over nested IRQ/NMI" from kvm/queue?
> It's probably best to deal with this in a new series rather than trying to
> squeeze it in.

With AMD we just have IRQ/NMI/SMI, and it's important to handle SMI in
check_nested_events because you can turn SMIs into vmexit without stuff
such as dual-monitor treatment. On the other hand there is no MTF and
we're not handling exceptions yet. So, since SMIs should be pretty rare
anyway, I'd rather just add a comment detailing the correct order and
why we're not following it. The minimal fix would be to move SMI above
the preemption timer, right?

Paolo