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

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

On 2015/1/30 20:26, Wei Liu wrote:
> 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.
>
>>>
>>> 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. :-)
>

Okay let me try do this.

Thanks
Tiejun