Re: [PATCH] target/s390x: Add a CONFIG switch to disable legacy CPUs

[Christian Borntraeger]

Am 14.06.24 um 09:15 schrieb Thomas Huth:
> On 14/06/2024 08.07, Christian Borntraeger wrote:
> > Am 13.06.24 um 19:07 schrieb Thomas Huth:
> > > Old CPU models are not officially supported anymore by IBM, and for
> > > downstream builds of QEMU, we would like to be able to disable these
> > > CPUs in the build. Thus add a CONFIG switch that can be used to
> > > disable these CPUs (and old machine types that use them by default).
> > >
> > > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > > ---
> > >   If you're interested, the PDF that can be downloaded from
> > >   https://www.ibm.com/support/pages/ibm-mainframe-life-cycle-history
> > >   shows the supported CPUs in a nice diagram
> >
> > z13 is still supported so the patch needs to be fixed at least.
>
> Oh, drat, I misread the diagram, indeed. 'should have looked at the table 
> instead :-/
>
> > Furthermore, z14 has the IBC/VAL cabability to behave like a z13,
> > same for z15. (we do support VAL to N-2)
>
> Hmm, so if z13 is still supported, and also has the possibility to do N-2, I 
> assume the z114/196 and z12 should still be considered as non-legacy, too?

Yes. z9 and older is no longer relevant (only for people that collect old HW) 
but the upstream kernel has an minimum requirement for z10 so maybe we still 
want to support that for testing purposes.
For upstream I prefer to keep the full list but I would be ok to hide those 
ancient things behind a config switch.