On Wed, Jul 18, 2007 at 10:40:48AM +0100, Richard W.M. Jones wrote: > Hugh Brock wrote: > >I'm looking at ways to replicate xm block-configure at the libvirt > >level. xm block-configure is useful in that it allows you to change the > >back device for an HVM guest while the guest is still running; this > >permits you for example to change the CDROM without shutting down your > >guest or poking around in xenstore. Thus we can have an "eject" button > >on cdrom devices in virt-manager (or "eject" and "load" buttons, I > >guess), which we really need. > > > >The issue of course is that xm block-configure is specifically intended > >for block devices and takes arguments for the back device and the front > >device (among others). We would naturally prefer to accept a block of > >XML just as virDomainAttachDevice does and then parse it, determine if > >the device in question is of a type we can actually edit, determine if > >the new backdev is appropriate, and so on. > > Definitely this will be useful for USB ... > > I think the question is: Should we have another entry point > (virDomainConfigureDevice), or should we just modify > virDomainAttachDevice so that if it sees XML for a device which is > already attached it just modifies the device? I don't mind too much either way. The only benefit a separate entry point would give is ability for an app to get an error back if they tried to modify a device which didn't exist. Whether they're separate or same entry point the underlying impls will be able to share a reasonable amount of code. > >None of this seems terribly hard, but before I go implement it, are > >there obvious pitfalls I'm not thinking? And given that > >virDomainAttachDevice is not implemented for qemud in libvirt (is it?), > >how do we handle the non-xen case? > > It seems like it isn't implemented for qemud. Changing the CD-ROM is > possible through the qemu monitor, so it should be. I intend to implement it when adding support for USB disk & device passthrough in QEMU/KVM. It will use the monitor for adding/removing USB devices on the fly. Likewise we can do CDROM media changes this way. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| -- Libvir-list mailing list Libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list