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

[Paolo Bonzini <pbonzini@redhat.com>]

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