Re: [PATCH] KVM/x86: Do not clear SIPI while in SMM

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 19 Apr 2024 12:17:01 -0400
boris.ostrovsky@oracle.com wrote:

> On 4/17/24 9:58 AM, boris.ostrovsky@oracle.com wrote:
> > 
> > I noticed that I was using a few months old qemu bits and now I am 
> > having trouble reproducing this on latest bits. Let me see if I can get 
> > this to fail with latest first and then try to trace why the processor 
> > is in this unexpected state.  
> 
> Looks like 012b170173bc "system/qdev-monitor: move drain_call_rcu call 
> under if (!dev) in qmp_device_add()" is what makes the test to stop failing.
>
> I need to understand whether lack of failures is a side effect of timing 
> changes that simply make hotplug fail less likely or if this is an 
> actual (but seemingly unintentional) fix.

Agreed, we should find out culprit of the problem.

PS:
also if you are using AMD host, there was a regression in OVMF
where where vCPU that OSPM was already online-ing, was yanked
from under OSMP feet by OVMF (which depending on timing could
manifest as lost SIPI).

edk2 commit that should fix it is:
    https://github.com/tianocore/edk2/commit/1c19ccd5103b

Switching to Intel host should rule that out at least.
(or use fixed edk2-ovmf-20240524-5.el10.noarch package from centos,
if you are forced to use AMD host)

> -boris
>