From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932831AbeAOLs6 (ORCPT + 1 other); Mon, 15 Jan 2018 06:48:58 -0500 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:57473 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233AbeAOLs4 (ORCPT ); Mon, 15 Jan 2018 06:48:56 -0500 X-ME-Sender: Date: Mon, 15 Jan 2018 09:48:51 -0200 From: Henrique de Moraes Holschuh To: Jia Zhang Cc: tony.luck@intel.com, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] x86/microcode/intel: Extend BDW late-loading with platform id and LLC check Message-ID: <20180115114851.npyeo4uztf5ww33o@khazad-dum.debian.net> References: <1515995003-113069-1-git-send-email-zhang.jia@linux.alibaba.com> <1515995003-113069-3-git-send-email-zhang.jia@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515995003-113069-3-git-send-email-zhang.jia@linux.alibaba.com> X-GPG-Fingerprint1: 4096R/0x0BD9E81139CB4807: C467 A717 507B BAFE D3C1 6092 0BD9 E811 39CB 4807 User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Mon, 15 Jan 2018, Jia Zhang wrote: > For more details, see erratum BDF90 in document #334165 (Intel Xeon > Processor E7-8800/4800 v4 Product Family Specification Update) from > September 2017. For the record, this erratum may well affect some E5v4 as well. Anything with a LLC/core ratio >= 2.5 is potentially affected as far as I could tell when I took a serious look at it months ago (based only on crash reports and public information). It would be safer to just blacklist by sig == 0x406f1, revision < 0x0b00021, and LLC/core ratio >= 2.5, ignoring platform IDs. > /* > * Late loading on model 79 with microcode revision less than 0x0b000021 > - * may result in a system hang. This behavior is documented in item > - * BDF90, #334165 (Intel Xeon Processor E7-8800/4800 v4 Product Family). > + * and LLC size per core bigger than 2.5MB may result in a system hang. > + * This behavior is documented in item BDF90, #334165 (Intel Xeon > + * Processor E7-8800/4800 v4 Product Family). > */ > if (c->x86 == 6 && > c->x86_model == INTEL_FAM6_BROADWELL_X && > c->x86_mask == 0x01 && > + llc_size_per_core(c) > 2621440 && > + c->platform_id == 0xef && > c->microcode < 0x0b000021) { > pr_err_once("Erratum BDF90: late loading with revision < 0x0b000021 (0x%x) disabled.\n", c->microcode); > pr_err_once("Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); The c->platform_id test looks wrong. The processor will only have a single bit set, it is the microcode update that has more than a single bit set. And do you really want 0xef? That is everyhing the public available microcode updates can be applied to in the first place, so even a corrected test would be useless (it would always match) unless you actually expect to find never-seen-in-the-wild platform mask 0x10? -- Henrique Holschuh