NAME

       msr - 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.

NOTES

       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

SEE ALSO

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

COLOPHON

       This page is part of release 4.15 of  the  Linux  man-pages  project.   A  description  of  the  project,
       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       https://www.kernel.org/doc/man-pages/.

Linux                                              2009-03-31                                             MSR(4)