Re: [PATCH] target/ppc/cpu-models: Update max alias to power10

[Murilo Opsfelder Araújo]

Hi, Thomas.

On 6/1/22 04:27, Thomas Huth wrote:
> On 31/05/2022 19.27, Murilo Opsfelder Araujo wrote:
> > Update max alias to power10 so users can take advantage of a more
> > recent CPU model when '-cpu max' is provided.
> >
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1038
> > Cc: Daniel P. Berrangé <berrange@redhat.com>
> > Cc: Thomas Huth <thuth@redhat.com>
> > Cc: Cédric Le Goater <clg@kaod.org>
> > Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
> > Cc: Fabiano Rosas <farosas@linux.ibm.com>
> > Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> > ---
> >   target/ppc/cpu-models.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/ppc/cpu-models.c b/target/ppc/cpu-models.c
> > index 976be5e0d1..c15fcb43a1 100644
> > --- a/target/ppc/cpu-models.c
> > +++ b/target/ppc/cpu-models.c
> > @@ -879,7 +879,6 @@ PowerPCCPUAlias ppc_cpu_aliases[] = {
> >       { "755", "755_v2.8" },
> >       { "goldfinger", "755_v2.8" },
> >       { "7400", "7400_v2.9" },
> > -    { "max", "7400_v2.9" },
> >       { "g4",  "7400_v2.9" },
> >       { "7410", "7410_v1.4" },
> >       { "nitro", "7410_v1.4" },
> > @@ -910,6 +909,8 @@ PowerPCCPUAlias ppc_cpu_aliases[] = {
> >       { "power8nvl", "power8nvl_v1.0" },
> >       { "power9", "power9_v2.0" },
> >       { "power10", "power10_v2.0" },
> > +    /* Update the 'max' alias to the latest CPU model */
> > +    { "max", "power10_v2.0" },
> >   #endif
>
> I'm not sure whether "max" should really be fixed alias in this list here? What if a user 
> runs with KVM on a POWER8 host - then "max" won't work this way, will it?

"-cpu max" as an alias to power10 running with KVM on a P8 host won't
work.  It's already broken with the current 7400_v2.9, anyway.

> And in the long run, it would also be good if this would work with other machines like 
> the "g3beige", too (which don't support the new 64-bit POWER CPUs), so you 
> should at least mention in the commit description that this is only a temporary hack for 
> the pseries machine, I think.

I agree.  I'll mention that if I end up respining the patch.

Thank you!

--
Murilo