Under specific microarchitectural circumstances, a register in "Zen 2"
CPUs may not be written to 0 correctly. This may cause data from another
process and/or thread to be stored in the YMM register, which may allow
an attacker to potentially access sensitive information (CVE-2023-20593,
also known as Zenbleed).
This update adds the microcode for Amd Epyc gen 2 cpus. Other Zen 2 based
CPUs will get their microcode update at a later time when Amd has fixed
and validated the microcodes, see the referenced Amd url that has info
about estimated timelines for various CPUs.