There are a few different issues:
-
AMD GPU’s prior to the 6000 series have a reset bug, where they could be passed through fine, once. Shutting down the VM and trying to pass it through again wouldn’t work because they get caught in some sort of bad state. Vendor Reset can mitigate this sometimes. My reference 6700 XT works great without any extra measures besides needing to load a vbios. My RX 460 required vendor reset, and also disabling of PCI power management (ASPM) in bios and grub boot settings to stop some crashes. There are rare reports of some 6000 series cards from the various vendors having reset issues, but it’s not been common.
-
The next issue is that very few AMD GPU’s support SR-IOV (which AMD’s implementation of is called “MxGPU”), which is basically taking a single GPU and being able to split it into multiple virtual ones. Your 6800XT is NOT one of the cards that supports this.
-
In relation to the previous issue, currently AMD is outright not interested in supporting SR-IOV in any manner that would be helpful to you. As far as AMD is concerned, SR-IOV/MxGPU only exist for an exclusive and manually selected group of high dollar businesses. Everyone else can go get fucked. There is some old, unmaintained and buggy driver code around called GIM that kinda makes the very old S7150 (which is SR-IOV capable) card work.
To summarize: Normal passthrough will work great on your 6800XT. SR-IOV functionality does not, and likely never will.