[libvirt] [RFC 00/28] s390x CPU models: exposing features

[Jiri Denemark]

On Wed, Jun 22, 2016 at 09:34:49 +0200, David Hildenbrand wrote:
> I think the coffee didn't do its work already :) . I wanted to write that we can
> _with_ this additional query. Meaning the involved overhead would be ok - in my
> opinion for s390x.
> 
> What we could do to avoid one compare operation would be:
> 
> a) Expand the host model
> b) Expand the target model (because on s390x we could have migration unsafe
> model)
> c) Work with the runnability information returned via query-cpu-definitions
> 
> But as we have to do b) either way on s390x, we can directly do a compare
> operation. (which makes implementation a lot simpler, because libvirt then
> doesn't have to deal with any feature/model names).

But why do you even need to do any comparison? Isn't it possible to let
QEMU do it when a domain starts? The thing is we should avoid doing
completely different things on each architecture.

Jirka