From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758530AbdHYUIY (ORCPT ); Fri, 25 Aug 2017 16:08:24 -0400 Received: from terminus.zytor.com ([65.50.211.136]:51655 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758516AbdHYUIW (ORCPT ); Fri, 25 Aug 2017 16:08:22 -0400 Date: Fri, 25 Aug 2017 13:04:48 -0700 From: tip-bot for Tony Luck Message-ID: Cc: hpa@zytor.com, davidcc@google.com, vikas.shivappa@linux.intel.com, ak@linux.intel.com, eranian@google.com, tony.luck@intel.com, fenghua.yu@intel.com, peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, ravi.v.shankar@intel.com, tglx@linutronix.de Reply-To: tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, ravi.v.shankar@intel.com, peterz@infradead.org, hpa@zytor.com, eranian@google.com, tony.luck@intel.com, vikas.shivappa@linux.intel.com, ak@linux.intel.com, davidcc@google.com, fenghua.yu@intel.com In-Reply-To: <3aea0a3bae219062c812668bd9b7b8f1a25003ba.1503512900.git.tony.luck@intel.com> References: <3aea0a3bae219062c812668bd9b7b8f1a25003ba.1503512900.git.tony.luck@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/cache] x86/intel_rdt: Turn off most RDT features on Skylake Git-Commit-ID: d56593eb5eda8f593db92927059697bbf89bc4b3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d56593eb5eda8f593db92927059697bbf89bc4b3 Gitweb: http://git.kernel.org/tip/d56593eb5eda8f593db92927059697bbf89bc4b3 Author: Tony Luck AuthorDate: Thu, 24 Aug 2017 09:26:52 -0700 Committer: Thomas Gleixner CommitDate: Fri, 25 Aug 2017 22:00:45 +0200 x86/intel_rdt: Turn off most RDT features on Skylake Errata list is included in this document: https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/6th-gen-x-series-spec-update.pdf with more details in: https://www.intel.com/content/www/us/en/processors/xeon/scalable/xeon-scalable-spec-update.html But the tl;dr summary (using tags from first of the documents) is: SKZ4 MBM does not accurately track write bandwidth SKZ17 CMT counters may not count accurately SKZ18 CAT may not restrict cacheline allocation under certain conditions SKZ19 MBM counters may undercount Disable all these features on Skylake models. Users who understand the errata may re-enable using boot command line options. Signed-off-by: Tony Luck Cc: Fenghua" Cc: Ravi V" Cc: "Peter Zijlstra" Cc: "Stephane Eranian" Cc: "Andi Kleen" Cc: "David Carrillo-Cisneros" Cc: Vikas Shivappa Link: http://lkml.kernel.org/r/3aea0a3bae219062c812668bd9b7b8f1a25003ba.1503512900.git.tony.luck@intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/intel_rdt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c index b641622..cd5fc61 100644 --- a/arch/x86/kernel/cpu/intel_rdt.c +++ b/arch/x86/kernel/cpu/intel_rdt.c @@ -769,6 +769,9 @@ static __init void rdt_quirks(void) if (!rdt_options[RDT_FLAG_L3_CAT].force_off) cache_alloc_hsw_probe(); break; + case INTEL_FAM6_SKYLAKE_X: + if (boot_cpu_data.x86_mask <= 4) + set_rdt_options("!cmt,!mbmtotal,!mbmlocal,!l3cat"); } }