Re: [Qemu-devel] [RFC 00/28] s390x CPU models: exposing features

[David Hildenbrand]

> Question: KVM supports x2apic (and enables it by default) on any
> host CPU, because it is all emulated by KVM. Should "host-model"
> include x2apic on all hosts, or only when the host CPU has it?
> ("-cpu host" does include it).
> 
> Including x2apic sounds more useful, but it doesn't match the
> "get as close to the host CPU as possible" part of your
> description.
> 

From a s390x point of view, our "host" model is about indicating the maximum
possible configuration we are able to virtualize, not strictly limiting it only
to the real host features.

We also have a feature called "sthyi", emulated by KVM, which might not be
around for the real "host". We will include that in "host", because otherwise
things seem to get really complicated with no obvious benefit (to me :) ).

Not sure how you want to handle that.

David