On 19.06.20 12:05, Cornelia Huck wrote: > On Fri, 19 Jun 2020 11:56:49 +0200 > David Hildenbrand <david@xxxxxxxxxx> wrote: > >>>>> For now this series covers just AMD SEV and POWER PEF. I'm hoping it >>>>> can be extended to cover the Intel and s390 mechanisms as well, >>>>> though. >>>> >>>> The only approach on s390x to not glue command line properties to the >>>> cpu model would be to remove the CPU model feature and replace it by the >>>> command line parameter. But that would, of course, be an incompatible break. >>> >>> Yuck. >>> >>> We still need to provide the cpu feature to the *guest* in any case, no? >> >> Yeah, but that could be wired up internally. Wouldn't consider it clean, >> though (I second the "overengineered" above). > > Could an internally wired-up cpu feature be introspected? Also, what Nope. It would just be e.g., a "machine feature" indicated to the guest via the STFL interface/instruction. I was tackling the introspect part when asking David how to sense from upper layers. It would have to be sense via a different interface as it would not longer be modeled as part of CPU features in QEMU. > happens if new cpu features are introduced that have a dependency on or > a conflict with this one? Conflict: bail out in QEMU when incompatible options are specified. Dependency: warn and continue/fixup (e.g., mask off?) Not clean I think. -- Thanks, David / dhildenb
