Copyright (c) 2009 Intel Corporation, Author Andi Kleen Some sentences copied from comments in arch/x86/kernel/msr.c %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under...
NAMEmsr - x86 CPU MSR access device
DESCRIPTION/dev/cpu/CPUNUM/msr provides an interface to read and write the model-specific registers (MSRs) of an x86 CPU. CPUNUM is the number of the CPU to access as listed in /proc/cpuinfo.
The register access is done by opening the file and seeking to the MSR number as offset in the file, and then reading or writing in chunks of 8 bytes. An I/O transfer of more than 8 bytes means multiple reads or writes of the same register.
This file is protected so that it can be read and written only by the user root, or members of the group root.
NOTESThe msr driver is not auto-loaded. On modular kernels you might need to use the following command to load it explicitly before use:
$ modprobe msr