Re: [Qemu-ppc] [RFC PATCH] spapr: support time base offset migration

[Benjamin Herrenschmidt]

On Thu, 2013-09-05 at 14:37 +0200, Alexander Graf wrote:

> Hrm, I think I'm starting to understand what this is about. So what we want is
> 
>   - timebase in guest
>   - timebase frequency in guest
>   - wall clock time in host
> 
> That way the receiving end can then take the timebase and add (new_timebase - 
> old_timebase) * tb_freq to the guest's time base.
> 
> Which gets me to the next question. Can we modify the tb frequency in guests?

No. It's architected at 512Mhz however since P7 I think. Not sure how we
did before, it's possible that P6 was the same (at least it's sourced
from more/less the same chip TOD facility).

Cheers,
Ben.