[Qemu-devel] Re: tainted Linux kernel in default SMP QEMU/KVM guests

[Anthony Liguori <anthony@codemonkey.ws>]

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
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