Re: Windows 8 VGA Passthrough

[John Wargo <wargo.john25@gmail.com>]

On 10/27/2013 05:51 PM, Gordan Bobic wrote:
> On 10/27/2013 09:01 PM, John Wargo wrote:
>> On 10/27/2013 02:35 PM, Gordan Bobic wrote:
>>> On 10/27/2013 04:21 PM, John Wargo wrote:
>>>> On 10/27/2013 09:27 AM, John Wargo wrote:
>>>>> On 10/27/2013 04:30 AM, Gordan Bobic wrote:
>>>>>> On 10/26/2013 09:58 PM, John Wargo wrote:
>>>>>>> Geniuses,
>>>>>>>
>>>>>>> I've been trying to get VGA pass-through working on Windows 8,
>>>>>>> however
>>>>>>> I've been running into a few issues.
>>>>>>> Currently I can get Windows 8 running flawlessly without VGA
>>>>>>> pass-through, however I'm planning on using it for gaming, so this
>>>>>>> wont
>>>>>>> work.
>>>>>>>
>>>>>>> When I start windows 8, I am able to get past the install 
>>>>>>> portion of
>>>>>>> the
>>>>>>> DVD, however it hangs on "Getting devices ready.. (n%)".
>>>>>>>
>>>>>>> Hardware Information :
>>>>>>> AMD Fx6300
>>>>>>> ASUS M5a99x evo r2.0
>>>>>>> 16GB RAM
>>>>>>> 6670 Radeon HD - Dom0
>>>>>>> 7850 Radeon HD - Win8
>>>>>>
>>>>>> I have recently (recently as in over the past 48 hours) re-tried to
>>>>>> get ATI VGA passthrough working, and the results are... interesting.
>>>>>>
>>>>>> HD4850 dom0 + HD7450 domU worked fine - or as fine as ATI 
>>>>>> passthrough
>>>>>> ever seems to work (slowdown + white lines when dragging windows
>>>>>> after a domU reboot). I am using XP64 domU so I can't eject the GPU
>>>>>> (it says it is being used). But shutting down the domU, doing echo 1
>>>>>> > reset for the GPU from dom0 (I don't know how this is implemented
>>>>>> and whether it does anything) and then starting it up again 
>>>>>> sometimes
>>>>>> recovers it. GPU-Z runs and reports the GPU correctly.
>>>>>>
>>>>>> HD4850 dom0 + HD7970 domU results in the entire host locking up as
>>>>>> soon as the driver is loaded in domU. My solution is to swap the 
>>>>>> dom0
>>>>>> GPU for an 8800GT, and the problem now doesn't occur. If I had to
>>>>>> guess, BIOS on the HD7970 does something bizzare, finds the 
>>>>>> HD4850 on
>>>>>> the bus, tries to do something to it, and ends up crashing the host.
>>>>>> This could also be exacerbated by the fact that I have to run with
>>>>>> relaxed checking and no PCI ACS due to NF200 bridges on my
>>>>>> motherboard. Even so, however, GPU-Z crashes the domU and it's GPU
>>>>>> _hard_ (but not the host, thankfully). It crashes it so hard, that
>>>>>> the only cure is to reboot the host. Reseting the GPU via /sys/
>>>>>> doesn't seem to do anything to help.
>>>>>>
>>>>>> Are you using gfx_passthru=1 in your config? The way most people 
>>>>>> have
>>>>>> this kind of thing working is with gfx_passthru=0, i.e. secondary
>>>>>> passthru. Don't assign the PCI device in the config when installing.
>>>>>> Once the domU install is complete, shut it down, and add the GPU you
>>>>>> want to pass through. Then fire up domU in VNC, install the driver,
>>>>>> and with a bit of luck it will come up with output on the external
>>>>>> monitor.
>>>>>>
>>>>>> Also make sure that radeon or radeonfb kernel drivers DO NOT load
>>>>>> before the device is assigned to xen-pciback. The exact way to 
>>>>>> ensure
>>>>>> this will depend on what distro and dom0 kernel you are using.
>>>>>>
>>>>>> Gordan
>>>>> Status update:
>>>>>
>>>>> The catalyst drivers appear to be working perfectly fine, device
>>>>> manager shows no errors, and everything works great, except that when
>>>>> I plug my monitor into the second card, I get "No Signal" on the
>>>>> monitor, then it shuts off.
>>>>>
>>>>> I though that secondary passthrough meant that it would pass the
>>>>> virtual adapter in as primary, but I could use my GPU that I passed
>>>>> through, so where am I wrong, and how do I do that?
>>>>>
>>>>> -John
>>>> I've been doing some research into my VGA passthrough, so I've gone
>>>> through the various debugging steps, and the only thing that I've 
>>>> found
>>>> out of place is with "xl dmesg" (attached).
>>>>
>>>> Where do I go from here?
>>>
>>> Sounds like your IOMMU may be buggy. You may need to set permissive=1
>>> on your xen-pciback module.
>>>
>>> I cannot remember if xl uses the same configuration, but for xm you
>>> could try putting this in your /etc/xen/xend-config.sxp:
>>> (pci-passthrough-strict-check no)
>>> (pci-dev-assign-strict-check no)
>>>
>>> Gordan
>>>
>> Gordan,
>>
>> After a bit of research, I was able to activate permissive mode on xen,
>> but I've got nothing, I'm still getting page faults.
>>
>> The page faults occur when the loading screen goes black (I'd assume
>> when it's trying to pass to the GPU)
>>
>> I've also tried setting (pci_msitranslate=0, along with changing
>> qemu=qemu-xen, but it doesn't help
>
> The correct incantation you seek is to put this in the config:
> device_model_version="qemu-xen-traditional"
>
> Gordan
Gordan,

Sorry for the confusion, I think that's what I meant by changing 
"qemu=qemu-xen", and I've been running off of "qemu-xen-traditional" up 
until I changed it.

I'm giving it another shot right now just in case though.

-John