* Eric Blake (eblake@xxxxxxxxxx) wrote: > On 09/24/2014 02:09 PM, Dr. David Alan Gilbert wrote: > > >> This right here is a problem. Qemu has explicitly documented that > >> anything beginning with x- may be subject to change or going away in a > >> later release, so libvirt policy has been to delay any patches > >> targetting an x- interface until upstream qemu renames it to drop the x- > >> to signify that it is now stable. So we can review your patches, but > >> can't apply them yet. > > > > It is a shame that libvirt doesn't have a similar mechanism which could > > be used in conjunction with qemu. My reason for currently leaving the x- > > in place is that while I don't expect the QML side to change, it seemed > > fair to put a new feature into QEMU without locking it down for the > > first cut. This seems to be normal practice in QEMU but invariably > > means that libvirt support is delayed. > > Libvirt DOES have the ability to issue raw monitor commands through > libvirt-qemu.so, and that might be sufficient for coding up the required > hacks. Not really. > Or, if the libvirt proof of concept patches here do the job, we > can feed that back to the qemu community as proof that the feature works > enough to lose the x- prefix right away, and commit ourselves to the > interface. The benefit of a proof-of-concept patch done in parallel is > that the moment the upstream qemu feature is no longer experimental, > libvirt can apply the patches right away, and downstream distros can > backport those packages in situations where .so stability is not violated. My difficulty here is that 'x-' is used to convey multiple things in qemu: 1) That the interface is unstable 2) That the feature is unstable and might disappear/change 3) That the feature is new and might change internally While we're reasonably happy with (1) and (2) I did want to be able to indicate (3) so that the onwire migration format of the postcopy wasn't locked in yet; however given that the x- is primarily intended to indicate interface stability, and we seem happy with that, I think I'll try dropping the x- and see what qemu-devel says when I try it. Dave -- Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list