Re: [PATCH] svm: Fix AVIC incomplete IPI emulation

["Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>]

Oren

On 3/13/19 8:05 PM, Oren Twaig wrote:
> Hi Suravee,
> 
> Turns out, the _same_ bug was already discussed in the past by
> yourself, Paolo and Radim (both now 'cc'-ed)
> 
> Please read it here:
> https://patchwork.kernel.org/patch/8292231/
> 
> 
> After reading that thread, I have couple of questions:
> 
> First,
> 
> You wrote : "I have tried NOT setting the IRR, and only
> kick_vcpu(). And things seem to work fine. Therefore, I think your
> analysis is likely to be correct."
> 
> AFAIU, it means that the below patch is wrong just as Paolo
> suggested in his original answer and you did fixed it back than, but the
> code is now back ?

Thanks for the recap. I was chasing a bug and totally forgot about this
discussion. I just found the reason why irr_pending was not set to 1 in my test,
which then causes the target vcpu to never get wake up and scheduled to process
the IRR bit that was set by AVIC as part of sending IPI.

I will send out a patch to revert and clean up this mess. Thanks for catching this.
And sorry for confusion.

Thanks,
Suravee