Xen devel - May 2013 - Re: [PATCH] libxl: allow an <emulator> to be selected in the domain config XML

On 01/05/13 09:46, Ian Campbell wrote:
> I would suggest that libvirt+libxl expose the version as the
"emulator"
> option and not the path. Just leave the path as the default in the
> normal case. You may also want to provide an extra
> emulator-path-override tag/attribute/XML for advanced users, but
that''s
> up to you.
>
> If you need to support upgrade from xend then you could perhaps treat
> <emulator> values not in the set of valid LIBXL_DEVICE_MODEL_VERSION
> string (currently "qemu-xen" and
"qemu-xen-traditional") as a path to a
> qemu-xen-traditional device model -- no xend user can possibly have been
> using the new device model with xend. Or you could take the approach
> that xl does and just warn.
This would work for me: it doesn''t seem too bad to consider
"qemu-xen"
and "qemu-xen-traditional" as special virtual paths. It''s a
useful
observation that xend never supported the new device model. Jim: should 
I cook up patch v3? :-)

Slightly tangentially, do you anticipate the list of valid 
LIBXL_DEVICE_MODEL_VERSIONs expanding in future? For example, will it be 
used to differentiate between different major versions of qemu?

Cheers,
Dave