Re: [Qemu-ppc] [PATCH v3] ppc: introduce CPUPPCState::cpu_dt_id

[Scott Wood]

On Tue, 2013-11-05 at 12:26 +1100, Alexey Kardashevskiy wrote:
> On 11/05/2013 06:42 AM, Scott Wood wrote:
> > On Mon, 2013-11-04 at 10:41 +0100, Alexander Graf wrote:
> >> What we really have are 3 semantically separate entities:
> >>
> >>   * QEMU internal cpu id
> >>   * KVM internal cpu id
> >>   * DT exposed cpu id
> >>
> >> As you have noted, it's a good idea to keep the QEMU internal cpu id
> >> linear, thus completely separate from the others. The DT exposed cpu id
> >> should be 100% local to hw/ppc/spapr*.c. I don't think any code outside
> >> of the DT generation and anything that accesses the "Virtual Processor
> >> Number" in sPAPR needs to care about the DT cpu id. All that code is
> >> 100% KVM agnostic.
> > 
> > This patch isn't just for sPAPR...  On e500 the DT cpu id is supposed to
> > match the MPIC cpu id.
> 
> 
> At least is my patch correct for e500?

I think so.

> I do not really know what is the difference between e500 and spapr in this 
> part.

e500 does not have sPAPR, and if the DT ID is "100% local to
hw/ppc/spapr*.c" then the MPIC code will have a problem.

Currently we don't support smt on e500 in QEMU, but e6500 (an
e500-derivative) does have smt, so it could happen in the future.

-Scott