[ovirt-users] Is it possible to disable qxl video?

[Martin Polednik]

On 11/07/16 09:46 +0000, Karli Sjöberg wrote:
>
>Den 11 jul 2016 11:37 fm skrev Arman Khalatyan <arm2arm at gmail.com>:
>>
>> I just testing several GPUs with pci-passthrough: GTX630, Tesla 2050 and FX5800.
>> None of them I got running with opengl/direct rendering inside the virtual machine.
>> I was thinking something to do with qxl driver, but after blacklisting it in the VMs kernel nothing was changed.
>> The VMs Xorg claiming always no display found even if I configure it with headless option: nvidia-xconfig -a --use-display-device=None --virtual=1280x1024
>> But with nvidia-smi I can see the GPU status, and I can run all cuda tests where opengl/X11 is not involved.
>> My test system is CentOS 7 with ovirt 4.
>> BTW If I clone VM which was not running, to real host on bare metal, everything is running as expecting.
>
>Don't remember If this was mentioned but have you tried doing the same thing but with virt-manager on a standalone host, just to rule out oVirt from the equation?

Also, the xorg must be setup to use the VFIO GPU. There is BusID
option in device section that must point to the guest address of the
GPU. I'm not sure if you've done that (and I'm quite sure it's missing
on the wiki, noted).

[in the guest]
$ lspci | grep VGA
03:00.0 VGA compatible controller: NVIDIA Corporation GM107GL [Quadro
K2200] (rev a2)

and  using the address, add device section to /etc/X11/xorg.conf

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BusID          "PCI:3:0:0"
EndSection

That should allow xorg to use the assigned GPU.

mpolednik

>/K
>>
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>>
>> ***********************************************************
>>
>>  Dr. Arman Khalatyan  eScience -SuperComputing
>>  Leibniz-Institut für Astrophysik Potsdam (AIP)
>>  An der Sternwarte 16, 14482 Potsdam, Germany
>>
>> ***********************************************************
>>
>> On Mon, Jul 11, 2016 at 9:06 AM, Martin Polednik <mpolednik at redhat.com> wrote:
>>>
>>> On 08/07/16 11:29 +0200, Michal Skrivanek wrote:
>>>>
>>>>
>>>>> On 06 Jul 2016, at 14:06, Francesco Romani <fromani at redhat.com> wrote:
>>>>>
>>>>>
>>>>> From: "Arman Khalatyan" <arm2arm at gmail.com>
>>>>> To: "users" <users at ovirt.org>
>>>>> Sent: Monday, July 4, 2016 11:52:24 AM
>>>>> Subject: [ovirt-users] Is it possible to disable qxl video?
>>>>>
>>>>>
>>>>> Hi,
>>>>> I am doing PCI Passthrough for GPUs.
>>>>> Is it possible somehow to disable/remove default video qxl?
>>>>> thanks,
>>>>> Arman,.
>>>>> Hi,
>>>>>
>>>>> The 4.0 Vdsm allows you to run a headless VM, meaning a VM without graphic device/frontend.
>>>>> Not sure Engine allows you that however.
>>>>
>>>>
>>>> no it doesn’t
>>>
>>>
>>> Even if engine allowed that, it may not be the correct solution.
>>>
>>> Running headless with PCI passthrough is considered primary VGA
>>> passthrough[1]. Using primary VGA passthrough without OVMF could cause
>>> (will cause) quite a bit of headaches.
>>>
>>> If you really want to try that, I assume using before_vm_start hook to
>>> remove the video device should be enough.
>>>
>>> [1] http://wiki.xenproject.org/wiki/Xen_VGA_Passthrough - it's
>>> possible to read about primary and secondary passthrough between the
>>> lines
>>>
>>>> However, if QXL is the problem (why is that so?) then you can switch to VGA(or CIRRUS if this is still 3.6)
>>>>
>>>>> I'm afraid you will need to write a Vdsm hook.
>>>>>
>>>>> There could be simpler solutions depending on the Engine
>>>>>
>>>>> Bests,
>>>>>
>>>>> --
>>>>> Francesco Romani
>>>>> RedHat Engineering Virtualization R & D
>>>>> Phone: 8261328
>>>>> IRC: fromani
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at ovirt.org <mailto:Users at ovirt.org>
>>>>> http://lists.ovirt.org/mailman/listinfo/users <http://lists.ovirt.org/mailman/listinfo/users>
>>>
>>>
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>>