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Help for identical GPUs vfio setup

Hello beautiful community!

I’d like to start off saying that I’m really sorry if I’m starting a new post for something that is already being discussed for a while. Also, I am really confused with this forum format and I’m kinda loss :sweat_smile:. (Been brought to "The VFIO and GPU Passthrough Beginner's Resource and I don’t get where I can ask questions :sweat:)

Alright, now with the subject at hand. I’ve been trying for a little over 12-13 hours to figure out how to setup my passthrough KVM. The thing is, I have two identical GPUs (GTX 1070) and it’s being one hardcore puzzle for me so far. I’ve followed a couple of tutorials and forums but I’m starting to get alienated :cold_sweat:.
Tutorials I’ve followed so far:

I’ve managed to get everything in order up to the point where I regen my initramfs (mkinitcpio -p linux56) but when I reboot, it gives me the sh /usr/bin/vfio-pci-override.sh Permission Denied echo. I tried chmoding the script with 777 but still brings me the permission denied. I asked for help on the manjaro forum and a nice guy brought me here.

The last of the three tutorials I linked seems to have found a solution. Although I do not understand much of it. How can I append pcie_acs_override=downstream,multifunction to my boot? Also, will I have to manually shutdown the second iommu group at each boot? Is there any step-by-step tutorials for identical GPUs on manjaro that I missed?

I wouldn’t mind restarting from scratch (already at my 3rd reinstallation of manjaro). Also I’d like to keep the second 1070 since the only other GPU that I have is a downgrade. I’d really like this to work since I don’t want to duel-boot anymore. Windows is kind of a pain (pc-breaking updates and having to reboot only to play a game).

Here’s my build:

  • Z170a PC Mate (updated bios and vt-d stuff enabled)
  • Manjaro 20.0 64bit XFCE (uefi and linux56 kernel)
  • i3 7100 (not overclocked)
  • 16Gb DDr4 @3200Mhz
  • 1000w Corsair RM1000i
  • 1Tb m.2 Drive
  • 2x GTX 1070 using proprietary drivers

Here’s my post on manjaro’s forum just in case: (https://forum.manjaro.org/t/i-need-help-about-vfio-using-two-identical-gpus/141058). I’d be happy to provide any information missing if needed. Thanks in advance for any help provided! Looking forward to enjoy a beautiful build without Billy G’s vulnerable OS on my grub :wink:.

Have a wonderful day to y’all and stay safe in this current situation!

Hey, GaduCouch

The formatting of your post was edited for clarity.

You can use `` (backticks) to surround a snippet of code for formatting.


Can you try running the script manually?

The reason it is vague is that there is more than one option to boot your system with. Grub and Systemdboot are the two options are common. You will have to figure out which one manjaro uses.
The arch wiki pages are written for arch users first and it assumes that they know which one they are using since they had to manually set it up.

Here is the wiki page on how to add kernel parameters.
https://wiki.archlinux.org/index.php/Kernel_parameters

Thank you @TheCakeIsNaOH for your fast answer and the info about the code formatting :D.

Will try right now to run the script manually.

Well I’m almost certain it is grub (like 95%), but will still look into it to be 100% sure. Will give some feedback a bit later. Thank again :smiley:

For grub, edit /etc/default/grub
Add the desired parameter to the line GRUB_CMDLINE_LINUX_DEFAULT="<parameters>" , leave any existing items in between the quotes.
Then save, run grub-mkconfig -o /boot/grub/grub.cfg and reboot.

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Oh boy… I did run the script manually but I actually have no clue how to know if it actually did something :sweat:.

Truth be told, I think this way too advanced for me at the moment :slightly_frowning_face:. I really appreciated your swift reply but I’m starting to think I should downgrade to my spare GPU until I get to know more about Unix Oses. Also, I don’t want to waste people’s time.

I like reading and learning, but this is kind of gibberish to me. I’m not through though, I will definitely give this another try (sooner than later), but at this point, I kinda want to use the PC :laughing:

Yeah I did those (with the special script for identical GPUs) and I get the permission denied at grub stage. I will reboot to check this one last time since it seems that the permission on the script had not been done for some reason. If it still echos me the permission denied, I’ll downgrade my second GPU for convenience.

Sadly, still not permitted. Thank you again kind sir!

Very appreciated and will try again in a near future :smiley:

I have heard getting VFIO setup compared to the final boss of linux. It’s not quite that bad, but it is not the easiest for people new to linux.

You are welcome.

1 Like

LOL! That’s how it feels at the moment :laughing:.

Although, it would seem that having two different GPU is much much easier.

Have a nice one and stay safe!

Well, now I have a crappy GPU for my linux but as I thought it was a thousand times easier to install the KVM :smiley: ! I had time to reinstall Manjaro and install all of this in like an hour compared to like 13 hours that ended up not working for identical GPUs.

Still will try again later though :stuck_out_tongue: