Subject: Re: [PATCH] powerpc/85xx: disable timebase synchronization under the hypervisor

From: Benjamin Herrenschmidt <[email-masked]>
Date: Wed, 15 Jun 2011 11:58:11 +1000

On Tue, 2011-06-14 at 18:25 -0500, Scott Wood wrote:
> On Tue, 14 Jun 2011 18:15:26 -0500
> Timur Tabi <[email-masked]> wrote:
> 
> > Scott Wood wrote:
> > > FWIW, it's not supported under KVM either -- though we don't support an SMP
> > > guest under KVM yet, and KVM silently ignores it rather than logs errors as
> > > the FSL HV does.
> > 
> > Does KVM set the root compatible to "fsl,P4080DS-hv"?
> 
> No, Qemu/KVM like to pretend they're fully emulating concrete hardware,
> even though there's stuff missing.
> 
> The only upstream e500 KVM platform is currently mpc8544ds.
> 
> For now, there's no SMP KVM guest support.  Maybe kexec can be fixed to not
> hard-reset the core by the time that changes. :-)

We might want to generically have a CPU feature bit indicating we are
running in guest vs. HV mode. I know Paulus is planning to introduce one
so you may want to sync with him.

Cheers,
Ben.