Re: [Xen-devel] [v2][PATCH] libxl: add one machine property to support IGD GFX passthrough

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2015/2/2 19:08, Ian Campbell wrote:
> On Mon, 2015-02-02 at 09:17 +0800, Tiejun Chen wrote:
> > When we're working to support IGD GFX passthrough with qemu
> > upstream, instead of "-gfx_passthru" we'd like to make that
> > a machine option, "-machine xxx,-igd-passthru=on". This need
> > to bring a change on tool side.
> > From which Qemu version is this new option accepted? What will a verison
> of qemu prior to then do when presented with the new option?
Sorry, maybe I'm not describing this correctly.

Actually qemu upstream never own this option, '-gfx_passthru' at all. 
This just exists alone in qemu-xen-traditional. So here I'm trying to 
introduce a new stuff that doesn't clash anything in qemu upstream.
So I guess I should rephrase this as follows:

    libxl: add one machine property to support IGD GFX passthrough

    When we're working to support IGD GFX passthrough with qemu
    upstream, we'd like to introduce a machine option,
    "-machine xxx,igd-passthru=on", to enable/disable that feature.
    And we also remove that old option, "-gfx_passthru", just from
    the case of LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN since actually
    no any qemu stream version really need or use that.

> (nb: you have an extra '-' in the description I think)
Yeah, I will remove that.

Thanks
Tiejun

> > Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> > ---
> > v2:
> >
> > * Based on some discussions with Wei we'd like to keep both old
> >    option, -gfx_passthru, and new machine property option,
> >    "-machine xxx,-igd-passthru=on" at the same time but deprecate
> >    the old one. Then finally we remove the old one at that point
> >    that to give downstream (in this case, Xen) time to cope with the
> >    change.
> >
> >   tools/libxl/libxl_dm.c | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> >
> > diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> > index c2b0487..8405f0b 100644
> > --- a/tools/libxl/libxl_dm.c
> > +++ b/tools/libxl/libxl_dm.c
> > @@ -701,6 +701,11 @@ static char ** 
> > libxl__build_device_model_args_new(libxl__gc *gc,
> >               flexarray_append(dm_args, "-net");
> >               flexarray_append(dm_args, "none");
> >           }
> > +        /*
> > +         * Although we already introduce 'igd-passthru', but we'd like
> > +         * to remove this until we give downstream time to cope with
> > +         * the change.
> > +         */
> >           if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
> >               flexarray_append(dm_args, "-gfx_passthru");
> >           }
> > @@ -748,6 +753,11 @@ static char ** 
> > libxl__build_device_model_args_new(libxl__gc *gc,
> >                                               machinearg, max_ram_below_4g);
> >               }
> >           }
> > +
> > +        if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
> > +            machinearg = libxl__sprintf(gc, "%s,igd-passthru=on", machinearg);
> > +        }
> > +
> >           flexarray_append(dm_args, machinearg);
> >           for (i = 0; b_info->extra_hvm && b_info->extra_hvm[i] != NULL; i++)
> >               flexarray_append(dm_args, b_info->extra_hvm[i]);
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel