rdmsr from userspace

[Rui Paulo]

Andriy Gapon 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?
> 

While I think this (devcpu) is good for testing and development, I 
prefer having a device driver to handle that specific MSR than a generic 
/dev/cpuN where you can issue MSRs.
Both for security and reliability reasons.

Regards,
-- 
Rui Paulo