Re: [PATCH v2] KVM: x86: avoid redundant REQ_EVENT

Paolo Bonzini
2016-12-15T14:32:50Z

On 15/12/2016 15:30, Radim Krčmář wrote:
>
> One useless round of KVM_REQ_EVENT is not going change nested
> performance by much and it is not the only thing we could improve wrt.
> TPR ... I would just leave it for now and take care of it when we
> * don't to update PPR at all with APICv -- it is already correct
> * drop the KVM_REQ_EVENT with flex priority, because lower TPR cannot
> unmask an interrupt

I agree. I still don't like the patch very much, because I feel like an
explicit state machine ("can KVM_REQ_EVENT do anything?") would be more
maintainable. But if I don't come up with anything we'll go with this
patch.

Paolo