Intel-Linux-Processor-Microcode-Data-Files VS Intel-Linux-Processor-Microcode-Dat

Intel distributes microcode updates for Linux here: https://github.com/intel/Intel-Linux-Processor-Microcode-Dat... , and the distro are all set up to pull from there and distribute automatically.

Not expert enough to know what to look for to see if these particular mitigations are present yet.

So where is the microcode update? I don't see anything for Linux yet.

https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/blob/main/releasenote.md looks like they released a new microcode (24000024) affecting these units on Feb 14th this year.

Package: intel-microcode Version: 3.20221108.1 Priority: optional Section: non-free/admin Maintainer: Henrique de Moraes Holschuh Installed-Size: 6460 kB Depends: iucode-tool (>= 1.0) Recommends: initramfs-tools (>= 0.113~) Conflicts: microcode.ctl (<< 0.18~0) Homepage: https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files Tag: hardware::TODO, role::app-data, use::driver Download-Size: 4509 kB APT-Sources: http://deb.debian.org/debian testing/non-free amd64 Packages Description: Processor microcode firmware for Intel CPUs

They have been sort of cracked, but it doesn't matter. The web or chain of trust of those updates from the vendor to the processor is what matters. They're at least CRC checked to prevent loading corrupt files.

https://ieeeaccess.ieee.org/featured-articles/reverseenginee...

https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

https://github.com/platomav/CPUMicrocodes

Not to “well aktchually”, but all modern processors do have regularly updated microcode that’s uploaded at boot time - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files

6-94-3 would become 6-5E-3. https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/blob/6c0c4691e5bb446e0e428ebca595164709c59586/intel-ucode/06-5e-03

OpenBSD kernel has no support for loading microcode on AMD CPUs, A number of issues/errata on AMD systems may be fixed as part of AGESA updates, in addition to microcode as part of BIOS/firmware updates. While there have been microcode updates released for Zen+ or newer CPUs, but these seem to be less frequent than Intel.

Intel distributes microcode updates for Linux here: https://github.com/intel/Intel-Linux-Processor-Microcode-Dat... , and the distro are all set up to pull from there and distribute automatically.

Not expert enough to know what to look for to see if these particular mitigations are present yet.

So where is the microcode update? I don't see anything for Linux yet.

https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

They have been sort of cracked, but it doesn't matter. The web or chain of trust of those updates from the vendor to the processor is what matters. They're at least CRC checked to prevent loading corrupt files.

https://ieeeaccess.ieee.org/featured-articles/reverseenginee...

https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

https://github.com/platomav/CPUMicrocodes

Is it anymore of a "magic incantation" than the linux-image-XYZ package which controls which OS kernel is installed?

If you want to see when Intel issues new microcode updates, it is all available on their GitHub: https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

It isn't clear if Haswell has this optimization. As an easy test you could run the zero-fill-bench linked in the post and check the fill0 vs fill1 numbers. If they are the same, Haswell probably never had this optimization in the first place.

Based on the Intel microcode release note [1] it doesn't seem like client HSW got any update this time, only HSX (Haswell Xeon).

---

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...