An msr is a "model specific register", a chicken bit can configure cpu features. They don't persist across a reboot, so you can't break anything. You can undo

An msr is a "model specific register", a chicken bit can configure cpu features. They don't persist across a reboot, so you can't break anything. You can undo what you just did without a reboot, just use `... & ~(1 << 9)` instead (unset the bit instead of set it).