Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

[Anthony Liguori <anthony@codemonkey.ws>]

On 01/07/2010 06:20 AM, Dor Laor wrote:
> On 01/07/2010 02:00 PM, Avi Kivity wrote:
>> On 01/07/2010 01:44 PM, Dor Laor wrote:
>>>> So if you had a 2.6.18 kernel and a 2.6.33 kernel, it may be necessary
>>>> to say:
>>>>
>>>> (2.6.33) qemu -cpu Nehalem,-syscall
>>>> (2.6.18) qemu -cpu Nehalem
>>>
>>>
>>> Or let qemu do it automatically for you.
>>
>> qemu on 2.6.33 doesn't know that you're running qemu on 2.6.18 on
>> another node.
>>
>
> We can live with it, either have qemu realize the kernel version out 
> of another existing feature or query uname.
>
> Alternatively, the matching libvirt package can be the one adding or 
> removing it in the right distribution.

There's another option.

Make cpuid information part of live migration protocol, and then support 
something like -cpu Xeon-3550.  We would remember the exact cpuid mask 
we present to the guest and then we could validate that we can obtain 
the same mask on the destination.

Regards,

Anthony Liguori

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