Re: [Qemu-devel] [PATCH] qmp: add BLOCK_MEDIUM_EJECT event

[Eric Blake <eblake@redhat.com>]

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On 01/24/2012 11:16 AM, Luiz Capitulino wrote:
> Libvirt wants to be notified when the guest ejects a medium, so that
> it can update its view of the guest.
> 
> This code has been originally written by Daniel Berrange. It adds
> the event to IDE and SCSI emulation.
> 
> Please, note that this only covers guest initiated ejects, that's,
> the QMP/HMP commands 'eject' and 'change' are not covered.
> 
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

Reviewed-by: Eric Blake <eblake@redhat.com>

>  
> +BLOCK_MEDIUM_EJECT
> +------------------
> +
> +Emitted when the guest succeeds ejecting a medium. If the device has a tray,

s/succeeds ejecting/succeeds at ejecting/

Since libvirt is also tracking whether it makes 'eject' and 'change'
monitor commands, and can also do a query when reconnecting to the
monitor after a libvirtd restart to see if state changed in the meantime
(when an event was lost), this should be sufficient for libvirt to have
an accurate picture of the device state.

I do have to wonder, however, if we also need an event for when the
guest initiates a tray lock or tray unlock event, in order to track
whether plain eject will work or whether a forced eject to override the
tray lock would be required.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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