2 Exact Same GPUs

[EclipzzeX]

I have 2 AMD RX580's (identical). Is it possible to have VFIO work?

[HikariKnight]

hi @EclipzzeX, from what i remember, it will get very tricky as they will share the same IDs. the whole RX4xx and Rx5xx series are detected as the same cards, but not impossible!

So you will have to create custom scripts that run in initramfs at boot (in terms of distros using initramfs-tools, no idea how to set it up on dracut and mkinitcpio, maybe look into those systems documentation if that is what your distro uses?)

Wendell has a guide for setting it up on initramfs here

This is not something my script does right now due to the added complexity it adds (since i try to support initramfs, dracut and mkinitcpio) hence why i have the requirement of using different gpus based on different architectures.

maybe the script will handle it in the future, but i lack 2 identical gpus to test with so it will be kinda hard for me to verify that things actually work as i like to actually test things and confirm the test case properly 😅

[jedrw]

Hi @HikariKnight, I've created a draft PR ( #32 ) that adds support for duplicate device IDs in dracut. I've tested this with a minor hack to trick it into thinking there are duplicate device IDs and I can successfully run a VM using a GPU bound with a custom initramfs module created by dracut. In theory this shouldn't be too difficult to replicate using initramfs-tools (and Wendell's write-up) and mkinitcpio.

I wanted to run this past you before I go do the work on the other two methods to be sure I haven't missed anything and that you're happy with the way I've implemented it?

As you mentioned above this is going to be tricky to test properly without second duplicate gpu. Do you know of any contributors who do who may be able to help test this?

[HikariKnight]

sadly @jedrw i know nobody with duplicate cards that can test this