Re: [Qemu-devel] [PATCH v2 08/18] nvdimm: init backend memory mapping and config data area

[Igor Mammedov]

On Thu, 17 Sep 2015 16:39:12 +0800
Xiao Guangrong <address@hidden> wrote:

> 
> 
> On 09/16/2015 12:10 AM, Paolo Bonzini wrote:
> >
> >
> > On 01/09/2015 11:14, Stefan Hajnoczi wrote:
> >>>>
> >>>> When I was digging into live migration code, i noticed that the same MR 
> >>>> name may
> >>>> cause the name "idstr", please refer to qemu_ram_set_idstr().
> >>>>
> >>>> Since nvdimm devices do not have parent-bus, it will trigger the abort() 
> >>>> in that
> >>>> function.
> >> I see.  The other devices that use a constant name are on a bus so the
> >> abort doesn't trigger.
> >
> > However, the MR name must be the same across the two machines.  Indices
> > are not friendly to hotplug.  Even though hotplug isn't supported now,
> > we should prepare and try not to change migration format when we support
> > hotplug in the future.
> >
> 
> Thanks for your reminder.
> 
> > Is there any other fixed value that we can use, for example the base
> > address of the NVDIMM?
> 
> How about use object_get_canonical_path(OBJECT(dev)) (the @dev is NVDIMM
> device) ?
if you use split backend/frotnend idea then existing backends
already have a stable name derived from backend's ID and you won't need to care
about it.