Re: [Qemu-devel] [PATCH 0/3] migration: export cap/params to qdev props

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Eduardo Habkost (ehabkost@redhat.com) wrote:
> On Fri, Jul 14, 2017 at 01:04:23PM +0800, Peter Xu wrote:
> > On Wed, Jul 12, 2017 at 04:05:58PM -0300, Eduardo Habkost wrote:
> > > On Wed, Jul 12, 2017 at 02:53:40PM +0800, Peter Xu wrote:
> > > [...]
> > > > These properties should only be used for debugging/testing purpose,
> > > > and we should not guarantee any interface compatibility for them (just
> > > > like HMP).
> > > 
> > > If we don't guarantee compatibility, the property names need to
> > > be prefixed with "x-".
> > 
> > Indeed. Sorry I missed that.
> > 
> > But I'd say it is slightly awkward to add "x-" for all these (for me,
> > "x-" means more like "this is not stable and experimental, use it
> > carefully", while this does not suite for this series). Maybe I can
> > just remove this sentence in commit log (I think I am just a little
> > bit frightened by the compatibility problems)...
> 
> "x-" in property names doesn't mean "experimental", but just "not
> part of the stable interface".  If you have the tiniest doubt
> about command-line compatibility, I think it won't hurt to use
> "x-".

We have:
    DEFINE_PROP_MIG_CAP("xbzrle", MIGRATION_CAPABILITY_XBZRLE),

so we could easily do:
    DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),

to ensure that all of the things we expose as props here have
that added fealing of uncertainty but don't change what migration
parameters see.


(It's a shame we have to have those lists manually, there are so
many manual places for each parameter and capability)

Dave

> 
> -- 
> Eduardo
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK