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From: Anthony Liguori <anthony@codemonkey.ws>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andre Przywara <andre.przywara@amd.com>,
	QEMU devel <qemu-devel@nongnu.org>,
	KVM list <kvm@vger.kernel.org>
Subject: Re: tainted Linux kernel in default SMP QEMU/KVM guests
Date: Fri, 19 Mar 2010 08:12:04 -0500	[thread overview]
Message-ID: <4BA37824.6000504@codemonkey.ws> (raw)
In-Reply-To: <4BA374F9.9040008@redhat.com>

On 03/19/2010 07:58 AM, Paolo Bonzini wrote:
>
>> 1) Change the default CPUID bits from 6/2/3 to 6/6/1, this passes the
>> Linux kernel check. But I am not sure if that would introduce
>> regressions, since some OSes apply quirks if they detect certain models
>> (like we had with the sysenter issue in the past)
>>
>> 2) Only change the CPUID bits to 6/6/1 if we use SMP. Still has the
>> above drawback, but would be limited to SMP guests only.
>>
>> 3) Set kvm64/kvm32 as the default CPU model if KVM is enabled. This
>> would limit the report and taint to TCG, where SMP is rarely used.
>> Additionally less people (if any) use it for production systems.
>>
>> 4) Make the Linux' kernel quirk dependent on the missing hypervisor bit.
>> I don't think this will be accepted easily upstream (and I don't want to
>> support Ingo's recent ideas ;-), also this would not fix older kernels.
>>
>> I can easily provide patches for all solutions, but I'd like to get
>> advice from people on which one to pursue.
>
> Doing (3) seems the most sensible thing to do, and it does not prevent 
> doing (1) later on for TCG only.

Let's switch to -cpu host for kvm.

Regards,

Anthony Liguori

> Paolo
> -- 
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


WARNING: multiple messages have this Message-ID (diff)
From: Anthony Liguori <anthony@codemonkey.ws>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andre Przywara <andre.przywara@amd.com>,
	QEMU devel <qemu-devel@nongnu.org>,
	KVM list <kvm@vger.kernel.org>
Subject: [Qemu-devel] Re: tainted Linux kernel in default SMP QEMU/KVM guests
Date: Fri, 19 Mar 2010 08:12:04 -0500	[thread overview]
Message-ID: <4BA37824.6000504@codemonkey.ws> (raw)
In-Reply-To: <4BA374F9.9040008@redhat.com>

On 03/19/2010 07:58 AM, Paolo Bonzini wrote:
>
>> 1) Change the default CPUID bits from 6/2/3 to 6/6/1, this passes the
>> Linux kernel check. But I am not sure if that would introduce
>> regressions, since some OSes apply quirks if they detect certain models
>> (like we had with the sysenter issue in the past)
>>
>> 2) Only change the CPUID bits to 6/6/1 if we use SMP. Still has the
>> above drawback, but would be limited to SMP guests only.
>>
>> 3) Set kvm64/kvm32 as the default CPU model if KVM is enabled. This
>> would limit the report and taint to TCG, where SMP is rarely used.
>> Additionally less people (if any) use it for production systems.
>>
>> 4) Make the Linux' kernel quirk dependent on the missing hypervisor bit.
>> I don't think this will be accepted easily upstream (and I don't want to
>> support Ingo's recent ideas ;-), also this would not fix older kernels.
>>
>> I can easily provide patches for all solutions, but I'd like to get
>> advice from people on which one to pursue.
>
> Doing (3) seems the most sensible thing to do, and it does not prevent 
> doing (1) later on for TCG only.

Let's switch to -cpu host for kvm.

Regards,

Anthony Liguori

> Paolo
> -- 
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2010-03-19 13:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-19 12:16 tainted Linux kernel in default SMP QEMU/KVM guests Andre Przywara
2010-03-19 12:16 ` [Qemu-devel] " Andre Przywara
2010-03-19 12:58 ` Paolo Bonzini
2010-03-19 12:58   ` [Qemu-devel] " Paolo Bonzini
2010-03-19 13:12   ` Anthony Liguori [this message]
2010-03-19 13:12     ` Anthony Liguori
2010-03-23 10:45     ` Avi Kivity
2010-03-23 10:45       ` [Qemu-devel] " Avi Kivity

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