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
http://www.kernel.org/doc/man-pages/.
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Copyright (c) 2009 Intel Corporation, Author Andi Kleen Some sentences copied from comments in arch/x86/kernel/msr.c 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 the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. |