Re: [Qemu-devel] [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Nov 03, 2014 at 01:01:03PM +0100, Paolo Bonzini wrote:
> 
> 
> On 03/11/2014 12:47, Chen, Tiejun wrote:
> > On 2014/11/3 19:36, Chen, Tiejun wrote:
> >> On 2014/11/3 19:35, Paolo Bonzini wrote:
> >>> On 03/11/2014 08:48, Chen, Tiejun wrote:
> >>>>>>>> I think the point was mostly to reserve 1f to prevent
> >>>>>>>> devices from using it.
> >>>>>>>> As we populate slots in order it doesn't seem to important ...
> >>>>>>>
> >>>>>>> If we populate slot at !1f GFX driver can't find this ISA bridge.
> >>>>>>
> >>>>>> Right, but I mean if no special options are used, 1f will typically
> >>>>>> stay free without any effort on our side.
> >>>>>
> >>>>> Yeah.
> >>>>>
> >>>>> Actually based on current info we know, seems 1f is just specific to
> >>>>> our
> >>>>> scenario :) So I always think we can occupy that. But Paolo and you
> >>>>> can
> >>>>> really determine this point.
> >>>>
> >>>> What's your idea?
> >>>
> >>> I do not have any objection to always occupying 1f for Xen IGD
> >>> passthrough.
> > 
> > After I go back to look at this again, I hope you don't misunderstand
> > what Michael mean now. He was saying we don't need to create a new
> > separate machine specific to IGD passthrough. But that idea is just from
> > you :)
> 
> It's difficult for me to follow, because xen_igd_passthrough_pc_hvm_init
> does not exist in the current tree.
> 
> The patches seem good to me; I was assuming that the new machine type
> would call xen_igd_passthrough_pc_hvm_init, but apparently I'm wrong?
> Paolo

Discussed on irc, Paolo said
<bonzini> so i don't really care how the ISA bridge is created

-- 
MST