Updated AMD Family 19h Microcode Published Following "Inception"

Following yesterday's disclosure of the AMD "Inception" security vulnerability and the Linux kernel patches merged for reporting the mitigation status as well as the kernel-based handling for earlier generation Zen CPUs, the Family 19h microcode mitigations have now been picked up by the linux-firmware.git repository.

Mitigating the Inception vulnerability for Zen 3 and Zen 4 processors mean updated microcode while earlier Zen CPUs can get by with the kernel patches alone. Today the AMD Family 19h CPU microcode was updated, which covers Zen 3 / Zen 3+ / Zen 4 processors.

The update today landed with this commit. As usual there is no formal change-log but simply:

* Update AMD cpu microcode for processor family 19h

Presumably it's just the Inception mitigation but there could be other fixes as well. In any case I'm working on some benchmarks to see if there is any performance impact from the change.

With the updated AMD Zen 3/4 microcode now merged into linux-firmware.git as the central repository for all the Linux microcode/firmware blobs, it will be easily picked up by all the Linux distributions that pull from there for shipping their Linux firmware updates to users.