3 ms·
The restriction on MSR writes from the kernel people is just nuts. It's like they are saying: we know better, you're stupid and shouldn't be doing this so we ju
by bitcharmer 5y ago
The restriction on MSR writes from the kernel people is just nuts. It's like they are saying: we know better, you're stupid and shouldn't be doing this so we just won't let you.
I'm still fuming.
- halz 5y agoContext: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/about/ https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/... Writes to arbitrary MSR are still allowed by linux, but it'll squawk a warning with the PID from what poked the MSR. What has been preventing writing to MSR is microcode updates (loaded via Linux via initram/firmware, or via the vendor in a BIOS update), such as the one(s) in response to plundervolt https://plundervolt.com/ https://plundervolt.com/ Writing to the plundervolt-related MSR was particularly helpful to undervolt a thermal-throttled laptop. So! Can either downgrade the BIOS and/or rollback the microcode that your distro is loading during boot.
- bitcharmer 5y agoThank you for providing context and some background. There are so many legitimate uses for wrmsr I still think this move from kernel devs is quite openly user hostile.