Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests

[Michael S. Tsirkin]

On Tue, Mar 21, 2017 at 05:02:25PM -0700, Nadav Amit wrote:
> 
> > On Mar 21, 2017, at 3:51 PM, Gabriel Somlo <gsomlo@xxxxxxxxx> wrote:
> > 
> > And I get the exact same results on the MacBookAir4,2 (which exhibits
> > no freezing or extreme sluggishness when running OS X 10.7 smp with
> > Michael's KVM MWAIT-in-L1 patch)...
> 
> Sorry for my confusion. I didnât read the entire thread and thought that
> the problem is spurious wake-ups.
> 
> Since that is not the case, I would just suggest two things that you can
> freely ignore:
> 
> 1. According to the SDM, when an interrupt is delivered, the interrupt
> is only delivered on the following instruction, so you may consider
> skipping the MWAIT first.
> 
> 2. Perhaps the CPU changes for some reason GUEST_ACTIVITY_STATE (which
> is not according to the SDM).
> 
> That is it. No more BS from me.
> 
> Nadav

Intersting. I found this errata:
A REP STOS/MOVS to a MONITOR/MWAIT Address Range May Prevent Triggering of
the Monitoring Hardware

Could the macbook CPU be affected?

-- 
MST