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

[Alexander Graf]

On 05.09.2013, at 16:26, Benjamin Herrenschmidt wrote:

> On Thu, 2013-09-05 at 16:14 +0200, Andreas Färber wrote:
> 
>> Are you thinking of POWER8 having a different frequency than POWER8 in
>> compat mode? Because migration from one -cpu to another is not supported
>> elsewhere.
>> 
>> Even if we want to migrate from one POWER7 revision to another, we
>> should let the destination use the revision of the source (guest ABI!),
>> via property if need be. Anything else will lead to confusion as to what
>> is supported and what is not. That -cpu host is the default for
>> convenience shouldn't relieve admins/libvirt to think about sensible
>> setups like they have to on x86.
> 
> Besides POWER8 uses 512Mhz too :-) It's been architected so it's
> unlikely to change from now on.

Ok, ditch the tb frequency then. We can always default to 512Mhz when it's 
absent.


Alex