I have two boxes with AMD Opteron 6262HE and 6386SE.
Both are reportedly vulnerable to Spectre v4, but it's reported that they don't need new microcode, only kernel patches.
I'm running 11-STABLE and have hw.spec_store_bypass_disable=1.
Even then I can see that hw.spec_store_bypass_disable_active is 0.
On another PC, with new Intel microcode from platomav repo, hw.spec_store_bypass_disable_active is 1, which suggests that something is wrong with SSBD for AMD.
SSBD on amd is not implemented.
(In reply to Konstantin Belousov from comment #1)
Then there should be some info to users that they are still vulnerable to variant 4 (at least in console when they switch hw.spec_store_bypass_disable).