[PATCH] virtinst: use 'host-passthrough' as default 'host' on AArch64

[Daniel P. Berrangé]

On Tue, Apr 07, 2020 at 08:01:50AM -0400, Liang Yan wrote:
> Thanks for the input.
> 
> On 4/7/20 3:54 AM, Andrea Bolognani wrote:
> > On Mon, 2020-04-06 at 16:51 -0400, Liang Yan wrote:
> >> virt-install already uses 'host-passthrough' as default when no setup
> >> for cmline '--cpu'. However, it will still use 'host-model' when comes
> >> with '-cpu host'. This will be a problem for aarch64 platfrom as
> >> 'host-model' for aarch64 kvm domain on aarch64 host is not supported yet.
> > 
> > virt-install's --cpu host maps to libvirt's
> > 
> >   <cpu mode='host-model'/>
> > 
> > while virt-install's --cpu host-passthrough maps to libvirt's
> > 
> >   <cpu mode='host-passthrough'/>
> > 
> > These semantics are not architecture dependent and, while the choice
> > of name is a bit unfortunate considering that QEMU's -cpu host and
> > virt-install's --cpu host have different meanings, I think they're
> > completely unambiguous and reasonably documented, and we should not
> > mess with them.
> > 
> 
> 
> virt-install supports both "host","host-mdoel" and "host-passthrough",
> "--cpu host" is mapped to "host-model" based on "cli:det_model_b",
> however if you check the default setup in "cpu"set_defaults", it has
> different configuration. Btw, it has different setup for different
> architecture already.  Nova also has different setup for aarch64 in my
> defense.
> 
> https://opendev.org/openstack/nova/commit/8bc7b950b7c0a3c80cdd120fe4df97c14848c344
> 
> 
> 
> I agree we could document this situation at least. It does block our
> aarch64 tests while it is ok for x86_64.

That is a bug in the tests - they shouldn't be trying to use a feature
which doesn't make sense for that arch,


Regards,
Daniel
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