Re: [Qemu-devel] [Xen-devel] [RFC][PATCH 1/1] libxl: add one machine property to support IGD GFX passthrough

[Xu, Quan]

> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On Behalf Of Wei Liu
> Sent: Friday, January 30, 2015 8:26 PM
> To: Chen, Tiejun
> Cc: Wei Liu; address@hidden; address@hidden; Ian Jackson;
> address@hidden; address@hidden; Gerd Hoffmann
> Subject: Re: [Xen-devel] [Qemu-devel] [RFC][PATCH 1/1] libxl: add one machine
> property to support IGD GFX passthrough
> 
> On Fri, Jan 30, 2015 at 08:56:48AM +0800, Chen, Tiejun wrote:
> [...]
> > >>>
> > >>>Just remember to handle old option in libxl if your old option is
> > >>>already released by some older version of QEMUs.
> > >>
> > >>I just drop that old option, -gfx_passthru, if we're under qemu
> > >>upstream circumstance, like this,
> > >>
> > >
> > >The question is, is there any version of qemu upstream that has been
> > >released that has the old option (-gfx-passthru)?
> >
> > No. Just now we're starting to support IGD passthrough in qemu upstream.
> >
> 
> Right, as of QEMU 2.2.0 there's no support of IGD passthrough in QMEU
> upstream.
> 

Just a question:
   Now what features do vt-d support? Thanks.

-Quan

> > >
> > >This gives us a situation that we need to support both the old
> > >(-gfx-passthru) and new (-igd-passthru) options. Presumably we
> > >(libxl) would need to fork a qemu process to determine which option
> > >it has and pass the right one.
> > >
> > >Or you can try to keep both old and new option at the same time but
> >
> > Yeah, actually I also have considered to keep both two options at the
> > same time. Its really friendly to any qemu version.
> >
> > >deprecate the old one. Then in a few qemu release cycles later (or
> >
> > This should be like 'accel=kvm' versus 'enable-kvm' in qemu upstream.
> > They're coexisted now but just the former is a modern option.
> >
> > >probably one year or two?) you can finally remove the old one. The
> > >point is that to give downstream (in this case, Xen) time to cope
> > >with the change.
> >
> > Here I'm fine to this way.
> >
> > So Gerd,
> >
> 
> So you don't actually need to ask Gerd this question because there is no old
> option to keep in qemu upstream.
> 
> Libxl (or any sensible toolstack) will just do the right thing to either pass
> -igd-passthru (or whatever you guys agree upon) to qemu upstream or pass
> -gfx-passthru to qemu traditional. :-)
> 
> Wei.
> 
> > What about this?
> >
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> address@hidden
> http://lists.xen.org/xen-devel