Luiz Capitulino <lcapitul...@redhat.com> writes: > Hi there, > > I need feedback on a new QMP event. > > Problem > ======= > > There's no way for a management tool to detect that a guest OS has ejected the > media in a CDROM or Floppy disk drive (I'm discarding polling, because it's > undesirable at best). > > The end result is that the management tool can get confused, this is happening > with libvirt when migration is involved: if the guest is saved/restored or > migrated, then libvirt will start the guest again with media still present. > > NOTE: Most of the analysis here was done by Daniel Berrange. > > Solution > ======== > > We need a new QMP event to solve that. There are two possible events, a > general one and a very specific one. > > There are 3 scenarios in which both events should be emitted: > > 1. When guest OS ejects media > 2. When 'eject' monitor command is run > 3. When 'change' monitor command is run > > BLOCK_MEDIA_CHANGE > ------------------ > > This is the general event, it's emitted when any removable block device > is changed. > > Ideally, the event should contain two pieces of info: > > - qdev device name > - new file path (to allow distinguishing eject from change) > > Example: > > { "event": "BLOCK_MEDIA_CHANGE", "data": { "qdev-id": "myid", > "new-path": > "/foo/bar/dir/distro.iso" }, > ... }
What if a host block device that isn't currently connected to a qdev goes through a media change? What if the connected qdev doesn't have an ID? > BLOCK_MEDIA_EJECT > ----------------- > > This event is only emitted when a CDROM or a floppy disk is ejected. > > The event contains one info one: > > - device name > > Example: > > { "event": "BLOCK_MEDIA_EJECT", "data": { "device-name": "ide1-cd0" }, ... } What makes CD-ROM and floppy special?