From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 2/2] PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interface Date: Mon, 25 Mar 2019 12:32:18 +0100 Message-ID: <20190325113218.GG12016@zn.tnic> References: <1637073.gl2OfxWTjI@aspire.rjw.lan> <1762575.ER2xjzr9E1@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <1762575.ER2xjzr9E1@aspire.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: x86 , LKML , Len Brown , Linux PM , Srinivas Pandruvada , Laura Abbott , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Simon Schricker , Borislav Petkov , Hannes Reinecke List-Id: linux-pm@vger.kernel.org On Thu, Mar 21, 2019 at 11:20:17PM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > 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 > --- > Documentation/ABI/testing/sysfs-devices-system-cpu | 18 ++++ > Documentation/admin-guide/pm/intel_epb.rst | 27 ++++++ > arch/x86/kernel/cpu/intel_epb.c | 93 ++++++++++++++++++++- > 3 files changed, 134 insertions(+), 4 deletions(-) Acked-by: Borislav Petkov -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.