Re: Default CPU models on s390x and ppc64

[Jiri Denemark]

On Thu, Oct 17, 2019 at 17:13:10 +0100, Peter Maydell wrote:
> On Thu, 17 Oct 2019 at 17:09, David Hildenbrand <address@hidden> wrote:
> > The default model under KVM is "host", under TCG it's "qemu". We should
> > not use "qemu" under KVM, although it might work on some setups ...
> 
> Possibly a tangent, but on Arm the approach we used to deal
> with "'-cpu host' only works for kvm" was to define a "-cpu max"
> meaning "best thing you can give me", which is an alias for
> -cpu host with KVM and an alias for a CPU with all the extra
> features we have emulation support under TCG. Then users can
> use '-cpu max' and have something that generally will DTRT
> regardless of accelerator.

This thread is not really about a CPU model that users could universally
use for both TCG or KVM. It's about checking what CPU model is used by
QEMU if no CPU model is specified on the command line.

BTW, I was told aarch64 is a bit different and QEMU fails to start with
KVM unless -cpu host is explicitly specified. Is that correct?

Jirka