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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20240924114051.1d5f7470@imammedo.users.ipa.redhat.com>
Date: Tue, 24 Sep 2024 11:40:51 +0200
From: Igor Mammedov <imammedo@...hat.com>
To: boris.ostrovsky@...cle.com
Cc: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini
 <pbonzini@...hat.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 Eric Mackay <eric.mackay@...cle.com>
Subject: Re: [PATCH] KVM/x86: Do not clear SIPI while in SMM

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

> On 4/17/24 9:58 AM, boris.ostrovsky@...cle.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
>