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Comment by whadawha | Hacker News Reader

Anyone have knowledge of whether microcode can be patched on consumer grade Intel CPUs?

https://github.com/intel/intel-linux-processor-microcode-dat...

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

Hot-swappable, even. TIL!

of course, it's hot-swap material, the microcode is 1st deployed by the bios, then the OS can apply changes as well.

Just that it's writable by $ (not #) feels awkward.

> Of course it’s hot-swap

Microcode updates like this didn’t exist when I first learned sysadmin, so I guess I don’t take such things for granted, sorry!

Yes? It is regularly; both the firmware or the OS can deliver updates depending on configuration. The Raptor Lake CPUs in question have gone through an enormous number of microcode revisions already due to quite famous voltage scaling issues; it's unclear if this errata is fallout from or related to a similar root cause or just another issue with the processor.

At boot time, the following package provides the latest Intel CPU microcode data files on NetBSD.

  sysutils/intel-microcode-netbsd

dmesg shows

  cpu 0: ucode 0xf0->0xf6
  cpu 1: ucode 0xf0->0xf6

Why is this downvoted? (At the time of writing, the text is grey, so it has at least a few downvotes.)

This is a good question. As others have noted below, yes, and sometimes you can see kernel logging on start-up when the microcode is loaded.

It's a dumb question, because it's in reply to a comment that already implies the answer, and it's trivial to find an answer online in less time than it takes to post that question and wait for someone to supply an answer.

The subject of CPU microcode update mechanisms is an interesting and relevant topic, but such a shallow, low-effort question is not a good way to promote interesting discussion on that topic.

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