Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751621AbeAPUB5 (ORCPT + 1 other); Tue, 16 Jan 2018 15:01:57 -0500 Received: from mail.skyhub.de ([5.9.137.197]:53764 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004AbeAPUBz (ORCPT ); Tue, 16 Jan 2018 15:01:55 -0500 Date: Tue, 16 Jan 2018 21:01:49 +0100 From: Borislav Petkov To: "Luck, Tony" Cc: Jia Zhang , "hmh@hmh.eng.br" , "mingo@redhat.com" , "hpa@zytor.com" , "tglx@linutronix.de" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2] x86/microcode/intel: Extend BDW late-loading with LLC size check Message-ID: <20180116200149.zffwdbjwj53ba7oj@pd.tnic> References: <1516021917-48335-1-git-send-email-zhang.jia@linux.alibaba.com> <20180115184616.r6pypjegywyd7ncm@pd.tnic> <2ddaecd3-c121-cb37-219e-0e7b1d17c22e@linux.alibaba.com> <3908561D78D1C84285E8C5FCA982C28F7B333F37@FMSMSX154.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7B333F37@FMSMSX154.amr.corp.intel.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Tue, Jan 16, 2018 at 05:24:27PM +0000, Luck, Tony wrote: > > I'll look for someone who can confirm the 2.5MB/core detail. > > Ok ... re-read the erratum. The 2.5MB/core is clear. The E5+E7 is clear. > > No mention of the platform ID, but Jia is dropping that part. > > Boris ... what specific questions remain? This magic: llc_size_per_core(c) > 2621440 as a reliable detection characteristic whether the patch is good to apply late. There must be a more reliable way to detect that. Also, the testing order is: llc_size_per_core(c) > 2621440 && c->microcode < 0x0b000021) { so if the LLC size per core check fails, the microcode revision being < 0x0b000021 doesn't matter. I.e., on machines with LLC-per-core < 2.5M, we can update even with revisions < 0x0b000021. Is that ordering correct? Also, this heuristic is not documented in the public doc AFAICT - I'm guessing that'll change soon...? Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.