PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interface

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The Performance and Energy Bias Hint (EPB) is expected to be set by
user space through the generic MSR interface, but that interface is
not particularly nice and there are security concerns regarding it,
so it is not always available.

For this reason, add a sysfs interface for reading and updating the
EPB, in the form of a new attribute, energy_perf_bias, located
under /sys/devices/system/cpu/cpu#/power/ for online CPUs that
support the EPB feature.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Borislav Petkov <bp@suse.de>

...

This commit is contained in:

Rafael J. Wysocki 2019-03-21 23:20:17 +01:00

parent 5861381d48

commit b9c273babc

3 changed files with 134 additions and 4 deletions

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18

Documentation/ABI/testing/sysfs-devices-system-cpu

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27

Documentation/admin-guide/pm/intel_epb.rst

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93

arch/x86/kernel/cpu/intel_epb.c

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