Re: [Xen-devel] vga passthrough with qemu-xen (or qemu upstream)

[Shakeel Butt <shakeel.butt@xxxxxxxxx>]

On Mon, Jan 20, 2014 at 7:29 AM, Gordan Bobic <gordan@xxxxxxxxxx> wrote:
> On 2014-01-20 15:19, Shakeel Butt wrote:
>>
>> On Mon, Jan 20, 2014 at 5:31 AM, Gordan Bobic <gordan@xxxxxxxxxx> wrote:
>>>
>>> On 2014-01-20 13:24, Wu, Feng wrote:
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: xen-devel-bounces@xxxxxxxxxxxxx
>>>>> [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of Gordan Bobic
>>>>> Sent: Monday, January 20, 2014 8:50 PM
>>>>> To: xen-devel@xxxxxxxxxxxxx
>>>>> Subject: Re: [Xen-devel] vga passthrough with qemu-xen (or qemu
>>>>> upstream)
>>>>>
>>>>> On 2014-01-20 12:31, Shakeel Butt wrote:
>>>>> > On Mon, Jan 20, 2014 at 4:09 AM, Stefano Stabellini
>>>>> > <stefano.stabellini@xxxxxxxxxxxxx> wrote:
>>>>> >> On Mon, 20 Jan 2014, Wu, Feng wrote:
>>>>> >>> > -----Original Message-----
>>>>> >>> > From: xen-devel-bounces@xxxxxxxxxxxxx
>>>>> >>> > [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of Shakeel
>>>>> >>> > Butt
>>>>> >>> > Sent: Monday, January 20, 2014 1:48 PM
>>>>> >>> > To: xen-devel@xxxxxxxxxxxxx
>>>>> >>> > Subject: [Xen-devel] vga passthrough with qemu-xen (or qemu
>>>>> >>> > upstream)
>>>>> >>> >
>>>>> >>> > Hi all,
>>>>> >>> >
>>>>> >>> > Is it possible to do vga passthrough on xen-unstable with
>>>>> >>> > qemu-xen
>>>>> >>> > as
>>>>> >>> > device model? I tried but I am getting error 'gfx_passthru'
>>>>> >>> > invalid
>>>>> >>> > parameter for qemu-xen. I am able to do passthrough with qemu
>>>>> >>> > traditional i.e. qemu-dm.
>>>>> >>>
>>>>> >>> As far as I know, only qemu-traditional supports vga pass-through
>>>>> >>> right now.
>>>>> >>
>>>>> >> Right.
>>>>> >> It is not possible to assign your primary VGA card to a VM with
>>>>> >> qemu-xen. You should be able to assign your secondary VGA card
>>>>> >> though.
>>>>> >
>>>>> > Let me understand this correctly. If I have two VGA cards then I can
>>>>> > passthrough
>>>>> > secondary VGA card (in Dom0) to HVM as its primary VGA card. Is this
>>>>> > right and
>>>>> > if yes how can I do it?
>>>>>
>>>>> Passing any VGA card as a primary-in-domU has always been problematic.
>>>>
>>>>
>>>>
>>>> I think passing VGA card as a primary-in-domU works well in
>>>> Qemu-traditional, right?
>>>
>>>
>>>
>>> I never managed to get it working - it certainly isn't just a matter of
>>> enabling the option. There is at least the matter of also side-loading
>>> the VGA BIOS, and IIRC that was limited to 64KB in size, which rules
>>> out all ATI and Nvidia GPUs of the past 2-3 generations.
>>>
>>> Having said that - I never found a particularly good use-case for
>>> primary passthrough. Once the GPU driver loads it works just the
>>> same for all intents and purposes.
>>>
>>
>> I have successfully managed to passthrough VGA card as primary to DomU
>> with qemu traditional. I am trying to do the same with upstream qemu
>> because
>>  I need some new features of the upstream qemu which are not available
>> in qemu traditional.
>>
>> With qemu upstream I can passthrough as secondary VGA card to DomU
>> and able to see it in device manager in DomU (Windows 7) but Windows
>> couldn't use it and display some error that another card is being used as
>> display. I want Windows to use the passthroughed vga card  as its display.
>
>
> Disable the other (emulated) card in device manager and reboot
> the domU. That should fix it.

This is not working for me. I am disabling the device and even uninstalling the
driver but on reboot Windows 7 install the driver for the emulated vga and
make it primary vga.

Is there a way to stop qemu upstream from emulating vga. I tried 'nographics'
in xl.conf but Windows still see the emulated vga.

Shakeel

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