See https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7005.html.
This is fixed in: * linux-4.14.321 * linux-4.19.290 * linux-5.4.252 * linux-5.10.189 * linux-5.15.125 * linux-6.1.44 * linux-6.4.9 There does not appear to be fixed microcode available yet. See also the situation in bug 911160. Note that each of these linux-* releases has a warning from Greg (https://lwn.net/Articles/940798): >Note, PLEASE TEST this kernel if you are on the [...] tree before using it in >a real workload. This was a quick release due to the obvious security fixes in >it, and as such, it has not had very much testing "in the wild". Please let us >know of any problems seen. Also note that the user/kernel api for the new >security mitigations might be changing over time, so do not get used to them >being fixed in stone just yet. ([...] because it's the same for each respective version, the LWN article just says 6.4.x, don't get the wrong impression).