Re: [Qemu-devel] [RFC 0/5]: QMP: Introduce GUEST_MEDIUM_EJECT & BLOCK_MEDIUM_CHANGED

[Kevin Wolf <kwolf@redhat.com>]

Am 10.02.2012 18:04, schrieb Luiz Capitulino:
> This reminds me about an earlier try where I did the following, iirc:
> 
>  1. added commands blockdev-tray-open, blockdev-tray-close, blockdev-medium-insert,
>     blockdev-medium-remove
>  2. added the events: BLOCK_TRAY_OPEN, BLOCK_TRAY_CLOSE, BLOCK_MEDIUM_INSERTED
>     BLOCK_MEDIUM_REMOVED, which would be emitted when the relating command is issued
>     (maybe the events could just be BLOCK_TRAY_CHANGED & BLOCK_MEDIUM_CHANGED)
>  3. re-wrote eject and change in terms of the new commands, note that you get the
>     events for free
> 
> Now, maybe the guest eject could also emit BLOCK_TRAY_OPEN & BLOCK_TRAY_CLOSE. Then
> I think this is a complete solution.
> 
> Do you guys agree?

Looks good to me in general. I'm not sure how you're imagining to
implement this, I would prefer not to emit events from the device code,
but only from block.c.

Another interesting point is what to do with host CD-ROM passthrough. I
think the TRAY_OPEN/CLOSE part is doable (do Paolo's patches actually do
that, so that we just need to add an event?). We would have to fake
MEDIUM_REMOVED/INSERTED immediately before a TRAY_CLOSE if the medium
has changed. LOCK/UNLOCK (which you forgot in your list) is only
initiated by the guest or monitor (eject -f), so there's nothing special
with passthrough.

Kevin