Re: [PATCH v1 2/9] s390x: toplogy: adding drawers and books to smp parsing

[Pierre Morel]

On 7/20/21 10:20 AM, Cornelia Huck wrote:
> On Tue, Jul 20 2021, Pierre Morel <pmorel@linux.ibm.com> wrote:
>
> > On 7/19/21 5:50 PM, Cornelia Huck wrote:
> > > On Fri, Jul 16 2021, Daniel P. Berrangé <berrange@redhat.com> wrote:
> > > > Is the book/drawer thing architecture specific, or is it machine
> > > > type / CPU specific. ie do /all/ the s390x machine types / CPUS
> > > > QEMU support the book/drawer concept, or only a subset.
> > >
> > > Should not be by machine type, but might be by cpu model (e.g. older
> > > hardware lacking the needed support for exposing this to the guest.) IBM
> > > folks, please correct me if I'm wrong.
> >
> >
> > Looks correct to me this is an information indicated by a facility
> > introduced with Z10 if I do not make an error.
>
> Hm. Would that become a problem if we made availability of parameters
> dependent upon a value in the machine (see the other thread I cc:ed you
> on?)

Why?
The parameter can always be there, it is just that with older cpu model 
we will not report the topology information to the guest.

The discussion on dies and on smp_dies_supported in this thread will be 
interesting to follow because in my opinion dies for X or books/drawers 
for Z are to be treated equally.

Regards,
Pierre

--
Pierre Morel
IBM Lab Boeblingen