Re: [PATCH v3 00/30] qapi/qom: QAPIfy --object and object-add

[Kevin Wolf]

Am 11.03.2021 um 12:24 hat Peter Krempa geschrieben:
> On Thu, Mar 11, 2021 at 09:37:11 +0100, Kevin Wolf wrote:
> > Am 11.03.2021 um 08:47 hat Peter Krempa geschrieben:
> > > On Wed, Mar 10, 2021 at 18:30:44 +0100, Kevin Wolf wrote:
> > > > Am 10.03.2021 um 15:31 hat Paolo Bonzini geschrieben:
> > > > > On 10/03/21 15:22, Peter Krempa wrote:
> 
> [...]
> 
> > > -object 
> > > memory-backend-ram,id=ram-node2,size=24578621440,host-nodes=1-2,host-nodes=5,host-nodes=7,policy=bind
> > 
> > Oh, we have ranges, too... That makes the compatibility code even
> > nastier to write. I doubt that we can implement this in the keyval
> > parser alone without touching the visitor. :-/
> > 
> > > If any of the above is to be deprecated we'll need to adjust our
> > > JSON->commandline generator accordignly.
> > > 
> > > Luckily the 'host-nodes' is storeable as a bitmap and the generator is
> > > actually modular to allow plugging an array interpretor which actually
> > > does the above conversion from a JSON array.
> > > 
> > > So, what is the preferred syntax here? Additionally we might need a
> > > witness property to detect when to use the new syntax if basing it on
> > > the object-add qapification will not be enough.
> > 
> > The list syntax supported by the keyval parser is the one you know from
> > -blockdev: host-nodes.0=3,host-nodes.1=7, ...
> 
> I think that should be easy enough to convert to.

We could also support JSON syntax in QEMU. That would probably be even
more convenient for libvirt?

> Is it safe to do right away (with the old parser?). Otherwise we need
> to agree on something which will let us detect when it's safe to
> change.

Neither keyval nor JSON syntax work with the old QemuOpts parser.

What is the usual way to do this for command line options? If we don't
have a good way there, we can always tie it to something in the QAPI
schema. If we still get this solved in time for 6.0, we could use the
existence of ObjectOptions. Or all else failing, we can use a feature
flag.

Kevin