RE: [PATCH v3 3/6] x86/microcode: Display revisions only when update is successful

From: Luck, Tony
Date: Fri Jan 06 2023 - 16:35:56 EST


> We issue that line unconditionally to give feedback to the user that the attempt
> was actually tried. Otherwise, you don't get any feedback and you wonder whether
> it is doing anything.
>
> The prev and next revision:
>
> "microcode revision: 0x%x -> 0x%x\n",
>
> will tell you whether something got loaded or not.

Seems like a very subtle indication of a possibly important failure.

E.g. There is some security update with new microcode to mitigate.

User downloads the new microcode. Runs:

# echo 1 > /sys/devices/system/cpu/microcode/reload

[This fails for some reason]

Looks at console

# dmesg | tail -1
microcode revision: 0x40001a -> 0x4001a

User doesn't notice that the version didn't change and thinks
that all is well.

Is there an earlier message that says something like this?

microcode: initiating update to version 0x5003f

-Tony