Commit-ID: d56593eb5eda8f593db92927059697bbf89bc4b3 Gitweb: http://git.kernel.org/tip/d56593eb5eda8f593db92927059697bbf89bc4b3 Author: Tony Luck <[email protected]> AuthorDate: Thu, 24 Aug 2017 09:26:52 -0700 Committer: Thomas Gleixner <[email protected]> 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 <[email protected]> Cc: Fenghua" <[email protected]> Cc: Ravi V" <[email protected]> Cc: "Peter Zijlstra" <[email protected]> Cc: "Stephane Eranian" <[email protected]> Cc: "Andi Kleen" <[email protected]> Cc: "David Carrillo-Cisneros" <[email protected]> Cc: Vikas Shivappa <[email protected]> Link: http://lkml.kernel.org/r/3aea0a3bae219062c812668bd9b7b8f1a25003ba.1503512900.git.tony.l...@intel.com Signed-off-by: Thomas Gleixner <[email protected]> --- 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"); } }
