Re: [PATCH 0/2] graphics passthrough with VT-d

[Andrew Lyon <andrew.lyon@gmail.com>]

On Fri, Aug 28, 2009 at 10:13 AM, Han, Weidong<weidong.han@intel.com> wrote:
> Andrew Lyon wrote:
>> On Fri, Aug 28, 2009 at 8:53 AM, Han, Weidong<weidong.han@intel.com>
>> wrote:
>>> Hi all,
>>>
>>> Recently, more and more people are interesting in gfx passthrough.
>>> But now xen-unstable doesn't support it, although some guys (Jean
>>> Guyader, Beng Heng, Ng) posted gfx passthrough patches. If
>>> xen-unstable includes gfx passthrough support, people can be easy to
>>> try it.
>>>
>>> gfx passthrough is more complicated than other PCI device
>>> passthrough such as NIC, and is hard to use a generic approach for
>>> all gfx passthrough. But there are some necessary changes for gfx
>>> passthrough:
>>>  1. disable emulated VGA adapter, instead use passthroughed gfx
>>>  2. load VGA bios of the gfx to guest
>>>  3. passthrough legacy VGA IO ports and MMIOs to guest
>>>
>>> This patchset implements above common changes. Based on the common
>>> changes, we are investigating to support more gfx cards and guest
>>> OSs. We will post the hacks in future.
>>>
>>> The patchset supports to passthrough the primary gfx and discrete
>>> gfx. With the patchset, virtualization friendly gfx cards can be
>>> passthroughed (e.g. Nvidia FX3800), IGD and many discrete gfx cards
>>> are not supported yet.
>>
>> What about cheaper cards in the FX range like the FX580 or FX1800, are
>> they likely to be passthrough friendly?
>
> I don't know. We didn't try those cards. You can try with our patch by yourself.
>
>>
>> Perhaps we should ask nvidia exactly which cards support
>> virtualization, or is it a feature that is listed in the tech specs?,
>
> No. we just find it works with the common changes. Actually, its VGA bios re-execution doesn't works well.

http://www.nvidia.com/object/sli_multi_os.html

Dual Quadro FX 5800, 4800, and 3800 professional graphics boards



>
> Regards,
> Weidong
>
>> I could probably run to one of the cheaper FX cards but the high end
>> ones are way too expensive for me to justify the cost.
>>
>> Andy
>>
>>>
>>> This is easy to use, the only difference from other PCI passthrough
>>> is to add following lines to hvm configure file:
>>>
>>> #----------------------------------------------------------------------------------------
>>> # 0: no gfx passthru, 1: IGD passthru, 2: discrete gfx passthru,
>>> default is 0
>>> gfx_passthru=2
>>>
>>> and also pls passthrough a USB controller for keyboard/mouse use in
>>> guest. (Now there are some issues on USB controller passthrough with
>>> pv-ops dom0, so currently prefer to use 2.6.18 dom0.)
>>>
>>>
>>> The patchset is as follows:
>>> 1. PATCH 1/2: changes in xen-unstable
>>>        - retrieves VGA bios from host VGA BIOS address (0xC0000),
>>> then load it to guest VGA BIOS address (This is the same with XCI).
>>>        - Enlarge guest MMIO range to contain gfx card's large memory
>>>        - add a config option 'gfx_passthru' for gfx passthrough
>>>
>>> 2. PATCH 2/2: changes in QEMU
>>>        - disable emulated VGA adapter
>>>        - register/unregister legacy VGA I/O ports and MMIOs
>>>
>>>
>>> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
>>> Signed-off-by: Weidong Han <weidong.han@intel.com>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xensource.com
>>> http://lists.xensource.com/xen-devel
>
>