MSR(4) - man - phpMan

MSR(4)                                Linux Programmer's Manual                               MSR(4)



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  Ap‐
       pendix B, for an overview of the Intel CPU MSRs.

COLOPHON
       This  page  is  part  of  release  5.10 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)