Comment 3 for bug 1950706

If there is an individual fix not regressing other functionality we can consider backporting it to 20.04 so it depends what this is about.

If OTOH you just want 20.04 in general but a newer stack of the virtualization software to run your newer HW you might consider trying [1].

I have not seen the very same on other EPYC Hardware last time I used it, but such issues often depend on the specific CPU and firmware levels.

If you could help isolating what we actually look for that would be great.
To do that I'd ask you to start with that PPA [1] I linked and the HWE kernels [2].
With that please upgrade kernel / qemu / libvirt individually - hopefully just one of them is needed to fix this for you, in that case this is the component we need to look in for individual changes and then provide you builds of that for 20.04+fix to test.

[1]: https://launchpad.net/~canonical-server/+archive/ubuntu/server-backports
[2]: https://wiki.ubuntu.com/Kernel/LTSEnablementStack