notme

How to check to see if Zenbleed mitigation(chicken bit) is properly set?

https://lemmy.world/post/2199197

How to check to see if Zenbleed mitigation(chicken bit) is properly set? - Lemmy.world

I’m a newb and ran the recommended mitigation code to set a chickent bit on my processor. After running it there was no indication that it worked. Is there a simple way to use rdmsr to check?

Jul 26, 2023 at 4:07pmWeb
Show threadtrachemysJul 26, 2023
echo $(($(rdmsr -c 0xc0011029) & (1<<9) ))

Should return 512. You might need a ‘sudo’ before the rdmsr (any permission errors in any of this means it didn’t work). Unfortunately, this needs to be done every time you reboot. The next security update for linux will do this automatically.

Show threadnotmeJul 26, 2023
Thanks, it works. That’s a bit worrying. Do you think Ubuntu 22.04 will get the security update soon? I got a microcode update today but i think that’s only a fix for server cpus and not desktop cpus.
Show threadryannathansJul 26, 2023
Microcode fixes the issue as of 3 days ago
Show threadnotmeJul 27, 2023
I thought that was only for Eypc processors with desktop processor fixes coming later this year. The articles are not very clear with what is fixed when.
Show threadYonatanAvharJul 27, 2023
I also read that fixes are being released now for the high-end chips, but the desktop fixes will be released significantly later