Re: [Qemu-devel] Unable to add ram object with same ID after addition, migration and removal at the target

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Bharata B Rao (2016-12-04 21:51:32)
> On Fri, Dec 2, 2016 at 11:46 PM, Dr. David Alan Gilbert <dgilbert@redhat.com>
> wrote:
> 
>     * Bharata B Rao (bharata.rao@gmail.com) wrote:
>     > Hi,
>     >
>     > - Add ram object and dimm device at the source
>     >
>     > (qemu) object_add memory-backend-ram,id=ram0,size=128M
>     > (qemu) device_add pc-dimm,id=dimm0,memdev=ram0
>     >
>     > - Migrate the VM and remove the dimm device and ram object at the target
>     >
>     > (qemu) device_del dimm0
>     > (qemu) object_del ram0
>     >
>     > - Adding the ram object with same id now at the target fails like this:
>     >
>     > (qemu) info memdev
>     >
>     > (qemu) object_add memory-backend-ram,id=ram0,size=128M
>     > Duplicate ID 'ram0' for object
>     >
>     > Same behaviour is seen on x86 and Power. The problem isn't seen if
>     > migration isn't involved (add, remove, add at the source itself).
> 
>     Is this the same as the one Michael Roth posted a fix for a few days
>     back; 'monitor: fix object_del for command-line-created objects'
> 
>     https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg05479.html
> 
> 
> Yes, this is same as above, I hadn't noticed Michael's fix.
> 
> Will be good to have this fix in 2.8.

I considered shooting for 2.8, but since it's only triggerable with HMP
(QMP doesn't use the QemuOpts-based parsing so it doesn't hit the
duplicate ID error, so libvirt in turn would be uneffected), and doesn't
seem to be a regression (AFAICT it's been an issue since object_del was
introduced), I figured it could wait till 2.9/2.8.1.

Definitely a pain for testing though...

> 
> Regards,
> Bharata.