Man Linux: Main Page and Category List


       msr - x86 CPU MSR access device


       /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 only be read and written  by  the
       user root, or members of the group root.


       The  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


       Intel Corporation Intel 64 and IA-32 Architectures Software Developer’s
       Manual Volume 3B Appendix B for an overview of the Intel CPU MSRs.


       This  page  is  part of release 3.24 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at