From: Paul Mackerras <paulus@samba.org>
To: Michael Ellerman <michael@ellerman.id.au>
Cc: linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org
Subject: Re: [PATCH] kvm/powerpc: Handle errors in secondary thread grabbing
Date: Tue, 16 Oct 2012 03:13:52 +0000 [thread overview]
Message-ID: <20121016031352.GK1218@drongo> (raw)
In-Reply-To: <1350346550-32539-1-git-send-email-michael@ellerman.id.au>
Michael,
On Tue, Oct 16, 2012 at 11:15:50AM +1100, Michael Ellerman wrote:
> In the Book3s HV code, kvmppc_run_core() has logic to grab the secondary
> threads of the physical core.
>
> If for some reason a thread is stuck, kvmppc_grab_hwthread() can fail,
> but currently we ignore the failure and continue into the guest. If the
> stuck thread is in the kernel badness ensues.
>
> Instead we should check for failure and bail out.
>
> I've moved the grabbing prior to the startup of runnable threads, to simplify
> the error case. AFAICS this is harmless, but I could be missing something
> subtle.
Thanks for looking at this - but in fact this is fixed by my patch
entitled "KVM: PPC: Book3S HV: Fix some races in starting secondary
threads" submitted back on August 28.
Regards,
Paul.
WARNING: multiple messages have this Message-ID (diff)
From: Paul Mackerras <paulus@samba.org>
To: Michael Ellerman <michael@ellerman.id.au>
Cc: linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org
Subject: Re: [PATCH] kvm/powerpc: Handle errors in secondary thread grabbing
Date: Tue, 16 Oct 2012 14:13:52 +1100 [thread overview]
Message-ID: <20121016031352.GK1218@drongo> (raw)
In-Reply-To: <1350346550-32539-1-git-send-email-michael@ellerman.id.au>
Michael,
On Tue, Oct 16, 2012 at 11:15:50AM +1100, Michael Ellerman wrote:
> In the Book3s HV code, kvmppc_run_core() has logic to grab the secondary
> threads of the physical core.
>
> If for some reason a thread is stuck, kvmppc_grab_hwthread() can fail,
> but currently we ignore the failure and continue into the guest. If the
> stuck thread is in the kernel badness ensues.
>
> Instead we should check for failure and bail out.
>
> I've moved the grabbing prior to the startup of runnable threads, to simplify
> the error case. AFAICS this is harmless, but I could be missing something
> subtle.
Thanks for looking at this - but in fact this is fixed by my patch
entitled "KVM: PPC: Book3S HV: Fix some races in starting secondary
threads" submitted back on August 28.
Regards,
Paul.
next prev parent reply other threads:[~2012-10-16 3:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-16 0:15 [PATCH] kvm/powerpc: Handle errors in secondary thread grabbing Michael Ellerman
2012-10-16 0:15 ` Michael Ellerman
2012-10-16 3:13 ` Paul Mackerras [this message]
2012-10-16 3:13 ` Paul Mackerras
2012-10-16 6:00 ` Michael Ellerman
2012-10-16 6:00 ` Michael Ellerman
2012-10-16 19:33 ` Benjamin Herrenschmidt
2012-10-16 19:33 ` Benjamin Herrenschmidt
2012-10-17 6:25 ` Alexander Graf
2012-10-17 6:25 ` Alexander Graf
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