Re: [Qemu-devel] [PATCH v2] monitor: allow object_del & device_del to accept QOM paths

[Eric Blake]

On 08/27/2015 11:26 AM, Programmingkid wrote:
> 
> On Aug 27, 2015, at 12:13 PM, Daniel P. Berrange wrote:
> 
>> Currently both object_del and device_del require that the
>> client provide the object/device short ID. While user
>> creatable objects require an ID to be provided at time of
>> creation, qdev devices may be created without giving an
>> ID. The only unique identifier they would then have is the
>> QOM object path.
>>
>> Allowing device_del to accept an object path ensures all
>> devices are deletable regardless of whether they have an
>> ID.
>>
>> (qemu) device_add usb-mouse
>> (qemu) qom-list /machine/peripheral-anon
>> device[0] (child<usb-mouse>)
>> type (string)
>> (qemu) device_del /machine/peripheral-anon/device[0]

> Your patch do the job, but could be tweaked. Could we make an alias for
> "qom-list /machine/peripheral-anon" that is actually easy to remember. 
> Perhaps "info devices". 
> 
> Also typing "device_del /machine/peripheral-anon/device[0]" seems 
> unnecessary. It probably 
> could be shortened to just "device_del device[0]". 

You're welcome to submit follow up patches to make HMP more useful to
you ('info' is already an HMP command, so adding an 'info devices'
submode is a reasonable addition).  However, the important change here
is the QMP change that management apps, like libvirt, will use; and that
interface does not need further syntactic sugar.  The patch specifically
distinguishes between full QOM paths (leading '/') and short names (no
leading '/'); and your proposal to try the QOM path under
/machine/peripheral-anon/ when given just the string 'device[0]' that
did not resolve to a short name is counter to that distinguishing
factor.  Besides, management apps don't care how long a string is.  The
QMP interface should not be changed, and any such simplifications you
write a patch for should be limited to the HMP side.

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

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