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

[Liang Yan]

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.


Best,
Liang