A message to fellow VFIO passthrough noobs

Hi, I was initially inspired to do GPU passthrough by Wendell-sama’s videos. I couldn’t make heads or tails of his guides, though. They were very verbose and I didn’t know what the hell the difference between QEMU, OVMF, VFIO, KVM, etc. etc. even was. I was running around like a chicken with its head cut off. Until I found these two guides:

Primarily: https://scottlinux.com/2016/08/28/gpu-passthrough-with-kvm-and-debian-linux/

Secondary: https://youtu.be/dsDUtzMkxFk

The first one does a very very good job of just telling you what you need to know to set things up as easily as possible. However, it was missing a couple of key things that were needed for my setup to work (i7 6700k + 980 Ti) that the secondary guide covered for me.

The first crucial point missing from the [primary] guide: You probably need to select the OVMF UEFI BIOS in the virt-manager VM creation Overview tab as mentioned at 11:51 of the [secondary guide] for your nvidia card to work. IF YOU DO NOT SELECT THIS IN VIRT MANAGER IN THE BEGINNING CREATION OF YOUR VM YOU WILL NOT BE ABLE TO CHANGE IT AND WILL HAVE TO CREATE A NEW ONE (https://youtu.be/dsDUtzMkxFk?t=710)

The second bit that the video made up for that the [primary] guide missed: the workaround for the dreaded Code 43 for nvidia is super easy to workaround and homie in the video does a great job guiding you through that process and the exact commands needed to implement it at 13:04 (https://youtu.be/dsDUtzMkxFk?t=784)

Anyway, I just thought I’d share my little solution to the headache of VFIO passthrough as a noob. Hopefully someone will read this and it won’t take them 2 weeks to figure it out like it did for me.

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The explanation of why you might need to recompile the kernel is from 6:11 to 6:40.

The reason is that pci devices in the same IOMMU group need to all be passed through the same VM. In many cases, the groups are fine, it might be fixed by using the ACS patch which needs to be compiled into the kernel.

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Oh, gotcha! I’ll edit that bit in my OP. Thanks for letting me know. Are you the creator of that video?

Nope, however the creator is on this forum and made a text version of his video- Play games in Windows on Linux! PCI passthrough quick guide

Yeah, I’m really into recompiling the kernel for no reason. :wink: