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

On 01.05.2013 16:11, Daniel P. Berrange wrote: > On Wed, May 01, 2013 at 02:44:11PM +0100, David Scott wrote: > >> 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? :-) >> > No, that really doesn't fly. The <emlator> element must always point > to a qualfied binary path. > > IMHO, libvirt should just default to the new QEMU binary and if people > want to use the old one, they can configure the emulator path for it. > What about stubdom? Any idea how to do it better than special paths? Even if given path will point to stubdom binary, I don't know how libvirt shoud distinguish it from standalone qemu and set b_info->device_model_stubdomain accordingly.