Re: [KVM TSC trapping / migration 2/2] Add TSC KHZ MSR

[Zachary Amsden]

On 01/06/2011 12:34 AM, Alexander Graf wrote:
> Am 06.01.2011 um 11:10 schrieb Zachary Amsden<zamsden@xxxxxxxxxx>:
>
>    
> > Use an MSR to allow "soft" migration to hosts which do not support
> > TSC trapping.  Rather than make this a required element of any
> > migration protocol, we allow the TSC rate to be exported as a data
> > field (useful in its own right), but we also allow a one time write
> > of the MSR during VM creation.  The result is that for the common
> > use case, no protocol change is required to communicate TSC rate
> > to the receiving host.
> >
> > This allows administrative tools to configure migration policy
> > as they see appropriate.  Rather than dictate this policy with the
> > KVM implementation, we properly allow migration to hosts which both
> > do and do not support setting of the TSC rate on the receiving end.
> > If it is wished to not support migration to a host which lacks
> > support for the TSC rate feature, that can be coordinated externally.
> >      
> Isn't there a real hw equivalent of such a register? It might make more sense to just implement that then.
>
>    

Unfortunately, no.
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