[vfio-users] Troubleshooting PCI Pass-through

[Torbjorn Jansson]

(not replying to gerson moises mail due to the weird quoting)

On 2016-08-14 04:21, Nicolas Roy-Renaud wrote:
> Make sure to quote what's already been said next time. Makes it more
> conveinient to follow.
>
>> It's pretty well guaranteed that a 500 series GeForce does not support
>> UEFI.  AFAIK, there's not a terribly high success rate with these cards
>> either.  The 600 series are generally what I consider the bottom end of
>> working reasonably well.  Otherwise there's not really enough
>> information in your report to provide any specific advice.  Thanks,
>>
>> Alex
> I don't think there's much to report, unfortunately.
>
> The problem is that VFIO passthroughs are made possible by a number of
> features and protocols introduced in the UEFI spec, which wasn't really
> needed on GPUs or anywhere back in 2010, when the GTX 500 series was
> released. When Windows 8 introduced secure boot, UEFI support accross
> the board became a requirement for most OEM PCs, so the vast majority of
> the hardware relased after that point supports it. Since secure boot had
> been making the news for a few months before that, I'm guessing the
> hardware manufacturers had also been given the heads up, so a number of
> 600 series card probably support it as well, like Alex said. Don't quote
> me on that, though, I'm looking things up as I go.
>
> If you really want to be sure on whether or not your GPU is UEFI
> compatible and you've already tried looking up the exact model on
> TechPowerup's database
> <https://www.techpowerup.com/vgabios/?architecture=NVIDIA&manufacturer=&model=GTX+570&interface=&memType=&memSize=>
> (it's not perfect, everything listed for my card says it's not EFI
> compatible), see if you can boot on a version of windows with EFI
> support (Windows 7+). If GPU-Z
> <https://www.techpowerup.com/downloads/SysInfo/GPU-Z/> detects your BIOS
> as UEFI compatible
> <https://hardforum.com/proxy/CKbSwA7n6I5vsWEN4M2hTs55Y2dEZAJiZ36gQuBpqPdTuA%3D%3D/image.png>,
> then you're in luck, but I wouldn't count on it.
>
> The point is, that card most probably won't work as a guest card. You
> could use it on the host, but you'd have to get a new card for the
> actual passthrough.
>
> -Nicolas
>

also note that there are some 600 series cards that as far as i 
understand uses the same gpu as 500 series cards.
nvidia tends to take some older gpus and introduce them in next gen 
series, probably for marketing reasons and as low cost cards.

i think my cheap old gt610 card is one of those.

also i was able to get vga pass thru on my gtx570 to work BUT it only 
worked once after a cold boot of the host, then second try of booting 
the vm resulted in a hard lock of the host 100% of the time.
so i would not even bother with those cards, too much trouble and high 
risk of lockups.

my new gtx970 works much better and uefi is the way to go.
makes life easier.

i believe the 700 series of cards also work and i think that's what alex 
used and wrote about in his blog series.
probably wont cost too much now with all the new cards.


> On 2016-08-12 15:14, gerson moises wrote:
>> Dear Mr. Alex WIlliamson,
>>
>> I have asked before about problems using Ubuntu and Windows as guests
>> for PCI Pass-through.
>> As Mr. Alex said, the success rate of GTX 570 cards is not high.
>> However, I would like to know how can I make a detailed
>> troubleshooting in this case for report purposes, I mean is there a
>> way I can find the cause of the problem by checking KVM or kernel logs
>> ? I am still a beginner in this area.
>>