[libvirt] [PATCH 4/9] qemu: Do not start with source for removable disks if tray is open

[Eric Blake]

On 03/11/2012 08:44 AM, Paolo Bonzini wrote:
> Il 05/03/2012 11:25, Osier Yang ha scritto:
>> This is similiar with physical world, one will be surprised if the
>> box starts with medium exists while the tray is open.
>>
>> New tests are added, tests disk-{cdrom,floppy}-tray are for the qemu
>> supports "-device" flag, and disk-{cdrom,floppy}-no-device-cap are
>> for old qemu, i.e. which doesn't support "-device" flag.
> 
> If the disk type is "block", and the source drive is a CD-ROM, the
> virtual tray state should be tied to the physical tray, even though this
> isn't always the case due to QEMU bugs.
> 
> Perhaps you should fail creation if the tray attribute is "open" in the
> above circumstances.  Another possibility is to forbid specifying the
> tray attribute completely.
> 
> Or you can just drop this patch, and only print the tray state in the
> virsh dumpxml output.  There are other attributes that already handled
> this way.

Are we trying to map the tray='open' to what the guest sees (in which
case, we should reject it for non-cdrom guest views), what the host sees
(even if the guest is viewing the storage as a non-cdrom IDE disk, but
the host storage backing that disk is a cdrom), or both?

I would argue that <target tray='open'/> should describe _only_ the
guest's view, regardless of host state (if host is even tying a physical
cdrom to the guest), and that if we _need_ the host state, that it
should be an optional element in <source>.

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

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