On 03. 03. 23, 9:44, Michael Pujos wrote:
On 3/3/23 07:52, Jiri Slaby wrote:
I need the write to MSR functionality to undervolt the CPU of my laptop.
How do you do that?
I use the intel-undervolt package that I maintain:
https://build.openbuildservice.org/package/show/hardware/intel-undervolt
Most undervolting tools do it by manipulating MSRs. Lockdown will break them.
Yeah, it definitely will as LOCKDOWN_MSR <= LOCKDOWN_INTEGRITY_MAX. Funny enough is that the voltage MSR is not even documented in the intel manual -- as far as I can see. So as I understand it, they are playing with some undocumented MSR, using some reverse engineered values. This is something which should be disabled anyway :P. If you really want to play with that register, you can implement a proper kernel module and sign it. regards, -- js suse labs