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

NAME         top

       msr - x86 CPU MSR access device

DESCRIPTION         top

       /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.

NOTES         top

       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         top

       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         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

Linux                                 2009-03-31                               MSR(4)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface

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