While Ray Tracing has been available on Linux with NVIDIA for a long time now, the open source RADV Mesa driver for AMD GPUs is lagging behind but more work is progressing on it.
Developer Bas Nieuwenhuizen put up a new blog post jokingly titled "World's Slowest Raytracer" to show how far it has come. It's worth remembering, that AMD RADV is not the official AMD driver for Linux, as they roll their own with Radeon Software for Linux but that's only supported across a few distributions and you're just almost always better off sticking with Mesa.
In the new post Nieuwenhuizen mentions that RADV and Ray tracing has got to a point where the conformance testing is coming back at about a 90% pass-rate "of non-skiped tests" so it's getting close to a usable state. However, it's still clearly far from finished.
The current work is also slow to that point that it "has like half the Windows performance at 4k right now and we still have some feature gaps to make it really usable for most games". Why is it so slow though? It's pretty simple really. First you get it working, then you optimize it.
What's next? Nieuwenhuizen mentions getting the conformance testing to pass and then getting a merge request setup to get it all upstreamed to the Mesa project. From there, the plan is to have "a minimal prototype going for some DXR 1.0 games with vkd3d-proton just to make sure we have the right feature coverage" and of course plenty of optimizations.