rdmsr from userspace

[Rui Paulo]

Mike Meyer wrote:
> On Sat, 17 May 2008 11:13:52 +0300
> Andriy Gapon <avg at icyb.net.ua> wrote:
>> It seems that rdmsr instruction can be executed only at the highest 
>> privilege level and thus is not permitted from userland. Maybe we should 
>> provide something like Linux /dev/cpu/msr?
>> I don't like interface of that device, I think that ioctl approach would 
>> be preferable in this case.
>> Something like create /dev/cpuN and allow some ioctls on it: 
>> ioctl(cpu_fd, CPU_RDMSR, arg).
>> What do you think?
> 
> Ok, this points directly at a question I've been wondering about, but
> haven't been able to find an answer in the google.
> 
> I've been mucking about with general access to sysctl's (a sysctl
> plugin for gkrellm, and a python module for accessing sysctls), and
> with that hammer in my hand, the nail for this problem is obviously a
> dev.cpu.#.msr sysctl.

How can you request a rdmsr within the sysctl tree? I don't think sysctl 
is appropriate here either.

-- 
Rui Paulo