From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753288AbeAFNuJ (ORCPT + 1 other); Sat, 6 Jan 2018 08:50:09 -0500 Received: from terminus.zytor.com ([65.50.211.136]:48897 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753139AbeAFNuH (ORCPT ); Sat, 6 Jan 2018 08:50:07 -0500 Date: Sat, 6 Jan 2018 05:48:48 -0800 From: tip-bot for Jia Zhang Message-ID: Cc: qianyue.zj@alibaba-inc.com, hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, tony.luck@intel.com, x86@kernel.org, mingo@kernel.org, bp@suse.de Reply-To: x86@kernel.org, tony.luck@intel.com, hpa@zytor.com, qianyue.zj@alibaba-inc.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, bp@suse.de In-Reply-To: <1514772287-92959-1-git-send-email-qianyue.zj@alibaba-inc.com> References: <1514772287-92959-1-git-send-email-qianyue.zj@alibaba-inc.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/microcode/intel: Extend BDW late-loading with a revision check Git-Commit-ID: b94b7373317164402ff7728d10f7023127a02b60 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 Return-Path: Commit-ID: b94b7373317164402ff7728d10f7023127a02b60 Gitweb: https://git.kernel.org/tip/b94b7373317164402ff7728d10f7023127a02b60 Author: Jia Zhang AuthorDate: Mon, 1 Jan 2018 10:04:47 +0800 Committer: Thomas Gleixner CommitDate: Sat, 6 Jan 2018 14:44:57 +0100 x86/microcode/intel: Extend BDW late-loading with a revision check Instead of blacklisting all model 79 CPUs when attempting a late microcode loading, limit that only to CPUs with microcode revisions < 0x0b000021 because only on those late loading may cause a system hang. For such processors either: a) a BIOS update which might contain a newer microcode revision or b) the early microcode loading method should be considered. Processors with revisions 0x0b000021 or higher will not experience such hangs. For more details, see erratum BDF90 in document #334165 (Intel Xeon Processor E7-8800/4800 v4 Product Family Specification Update) from September 2017. [ bp: Heavily massage commit message and pr_* statements. ] Fixes: 723f2828a98c ("x86/microcode/intel: Disable late loading on model 79") Signed-off-by: Jia Zhang Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Tony Luck Cc: x86-ml Cc: # v4.14 Link: http://lkml.kernel.org/r/1514772287-92959-1-git-send-email-qianyue.zj@alibaba-inc.com --- arch/x86/kernel/cpu/microcode/intel.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 8ccdca6..d9e460f 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -910,8 +910,17 @@ static bool is_blacklisted(unsigned int cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); - if (c->x86 == 6 && c->x86_model == INTEL_FAM6_BROADWELL_X) { - pr_err_once("late loading on model 79 is disabled.\n"); + /* + * 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). + */ + if (c->x86 == 6 && + c->x86_model == INTEL_FAM6_BROADWELL_X && + c->x86_mask == 0x01 && + 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"); return true; }