linux-kernel - [PATCH v3 0/2] x86/resctrl: Work around MBM errata

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Message-Id: <20201014004927.1839452-1-fenghua.yu@intel.com>
Date:   Wed, 14 Oct 2020 00:49:25 +0000
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Borislav Petkov" <bp@...en8.de>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>,
        "Stephane Eranian" <eranian@...gle.com>,
        "Tony Luck" <tony.luck@...el.com>,
        "Reinette Chatre" <reinette.chatre@...el.com>,
        "Randy Dunlap" <rdunlap@...radead.org>,
        "Ravi V Shankar" <ravi.v.shankar@...el.com>
Cc:     "linux-kernel" <linux-kernel@...r.kernel.org>,
        "x86" <x86@...nel.org>, Fenghua Yu <fenghua.yu@...el.com>
Subject: [PATCH v3 0/2] x86/resctrl: Work around MBM errata

Intel Memory Bandwidth Monitoring (MBM) counters may report system
memory bandwidth incorrectly on some Intel processors. The errata are
reported in erratum SKX99 [1], erratum BDF102 [2] and RDT reference
manual [3].

The errata are worked around using a correction factor table. Since
the correction factor table is not publicly documented anywhere, it's
documented in Documentation/x86/resctrl.rst along with the errata.

1. Erratum SKX99 in Intel Xeon Processor Scalable Family Specification
   Update:
http://web.archive.org/web/20200716124958/https://www.intel.com/content/www/us/en/processors/xeon/scalable/xeon-scalable-spec-update.html
2. Erratum BDF102 in Intel Xeon E5-2600 v4 Processor Product Family
   Specification Update:
http://web.archive.org/web/20191125200531/https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e5-v4-spec-update.pdf
3. The errata in Intel Resource Director Technology (Intel RDT) on 2nd
   Generation Intel Xeon Scalable Processors Reference Manual:
https://software.intel.com/content/www/us/en/develop/articles/intel-resource-director-technology-rdt-reference-manual.html

Change Log:
v3:
- Remove unnecessary conf.py change in patch 1 (Randy).

v2:
- Document the errata and the correction table in resctrl.rst (Boris).
- Address various comments on patch 2 (Boris).
- Change the documentation URLs to stable archive.org (Tony).

Fenghua Yu (2):
  Documentation: x86: Rename resctrl_ui.rst and add two errata to the
    file
  x86/resctrl: Correct MBM total and local values

 Documentation/x86/index.rst                   |  2 +-
 .../x86/{resctrl_ui.rst => resctrl.rst}       | 82 +++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/core.c            |  4 +
 arch/x86/kernel/cpu/resctrl/internal.h        |  1 +
 arch/x86/kernel/cpu/resctrl/monitor.c         | 82 ++++++++++++++++++-
 5 files changed, 168 insertions(+), 3 deletions(-)
 rename Documentation/x86/{resctrl_ui.rst => resctrl.rst} (92%)

-- 
2.28.0