[PATCH v1 0/2] s390x/cpumodel: Introduce "best" model variants

[David Hildenbrand <david@redhat.com>]

There was recently a discussion regarding CPU model versions. That concept
does not fit s390x where we have a lot of feature variability. I
proposed an alternative approach in [1], which might work for x86 as well
(but I am not sure if x86 still can or wants to switch to that), and
requires no real changes in upper layers.

[1] and patch #2 contains more information on the motivation for this.

E.g., specifying/expanding "z14-best" will result in the "best feature
set possible on this accelerator, hw and, firmware". While a "z13" does
not work under TCG and some z/VM versions, "z13-best" will work.

As I had a couple of spare minutes this week, I hacked a quick prototype.
I did not heavily test this (quick sanity tests under TCG only), but it
should be decent enough to get the idea and play with it. I'll not be
working next week, which is why I sent this out now for discussion.

[1] https://lists.gnu.org/archive/html/qemu-devel/2019-10/msg07222.html

Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Jiri Denemark <jdenemar@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Michael Mueller <mimu@linux.ibm.com>

David Hildenbrand (2):
  s390x/cpumodels: Factor out CPU feature dependencies
  s390x/cpumodel: Introduce "best" model variants

 target/s390x/cpu-qom.h    |   1 +
 target/s390x/cpu_models.c | 211 +++++++++++++++++++++++++++-----------
 2 files changed, 153 insertions(+), 59 deletions(-)

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