Re: [Qemu-devel] [PATCH v3] monitor: allow object_del & device_del to accept QOM paths

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Sep 01, 2015 at 03:17:29PM +0200, Andreas Färber wrote:
> Am 01.09.2015 um 11:50 schrieb Daniel P. Berrange:
> > 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]
> > 
> > Although objects require an ID to be provided upfront,
> > there may be cases where the client would prefer to
> > use QOM paths when deleting.
> > 
> > Devices are required to be marked as hotpluggable
> > otherwise an error is raised
> > 
> >  (qemu) device_del /machine/unattached/device[4]
> >  Device 'PIIX3' does not support hotplugging
> > 
> > Similarly objects are required to implement the
> > user-creatable interface
> > 
> >  (qemu) object_del /machine/unattached/device[4]
> >  /machine/unattached/device[4] is not a user-creatable object
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> > 
> > Changed in v3:
> > 
> >  - Add type checks to avoid assertion failures if user
> >    supplied path is not of type device or user-creatable
> > 
> >  hmp-commands.hx  |  6 ++++--
> >  qapi-schema.json |  4 ++--
> >  qdev-monitor.c   | 19 ++++++++++++++-----
> >  qmp-commands.hx  | 13 +++++++++++--
> >  qmp.c            | 15 ++++++++++++---
> >  5 files changed, 43 insertions(+), 14 deletions(-)
> > 
> > diff --git a/hmp-commands.hx b/hmp-commands.hx
> > index d3b7932..c0c113d 100644
> > --- a/hmp-commands.hx
> > +++ b/hmp-commands.hx
> > @@ -675,7 +675,8 @@ ETEXI
> >  STEXI
> >  @item device_del @var{id}
> >  @findex device_del
> > -Remove device @var{id}.
> > +Remove device @var{id}. @var{id} may be a short ID
> > +or a QOM object path.
> 
> Have you considered using two alternative parameters, id and qom-path?
> (qom_path was used elsewhere)

I'm not fussed either way, but I thought it simpler to not try to change
the accepted parameters of the existing commands.  Looking, the only
place I notice that uses a 'qom_path' is the return data in the CpuInfo
struct.

Does anyone have strong feelings either way about use of id for both vs
qom-path or id ?

Regards,
Daniel
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