Re: [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul

Maxim Levitsky
2021-12-09T06:32:16Z

On Thu, 2021-12-09 at 01:37 +0000, Sean Christopherson wrote:
> On Thu, Dec 09, 2021, Maxim Levitsky wrote:
> > On Thu, 2021-12-09 at 01:00 +0200, Maxim Levitsky wrote:
> > > Probably just luck (can't reproduce this anymore) but
> > > while running some kvm unit tests with this patch series (and few my patches
> > > for AVIC co-existance which shouldn't affect this) I got this
> > >
> > > (warning about is_running already set)
>
> ...
>
> > Also got this while trying a VM with passed through device:
>
> A tangentially related question: have you seen any mysterious crashes on your AMD
> system? I've been bisecting (well, attempting to bisect) bizarre crashes that
> AFAICT showed up between v5.15 and v5.16-rc2. Things like runqueues being NULL
> deep in the scheduler when a CPU is coming out of idle. I _think_ the issues have
> been fixed as of v5.16-rc4, but I don't have a good reproducer so bisecting in
> either direction has been a complete mess. I've reproduced on multiple AMD hosts,
> but never on an Intel system. I have a sinking feeling that the issue is
> relatively unique to our systems :-/

I did had my 3970X lockup hard once on 5.16-rc2. It locked up completely without even
sending anything over a a pcie serial port card I.

I don't remember what I was doing during the crash but probably had some VMs running.

Since then it didn't happen again, and I am running 5.16-rc3 for some time
with Paolo's kvm/queue merged and my own patches.

>
> And a request: any testing and bug fixes you can throw at the AVIC changes would be
> greatly appreciated. I've been partially blocked on testing the AVIC stuff for the
> better part of the week. If the crashes I'm seeing have been resolved, then I should
> be able to help hunt down the issues, but if not...
>

This is what I started doing last evening, and I'll go through all of the usual testing
I do soon.

Best regards,
Maxim Levitsky