From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753129AbeAZNwq (ORCPT ); Fri, 26 Jan 2018 08:52:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37910 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752819AbeAZNuD (ORCPT ); Fri, 26 Jan 2018 08:50:03 -0500 Message-ID: <1516974600.2801.10.camel@redhat.com> Subject: Re: [PATCH] x86/microcode/intel: print previous microcode revision during early update From: Petr Oros Reply-To: poros@redhat.com To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Date: Fri, 26 Jan 2018 14:50:00 +0100 In-Reply-To: <20180126115800.bvqrzik2f3hmmiah@pd.tnic> References: <20180126103451.16863-1-poros@redhat.com> <20180126104109.slxxoq4vkqytqjxd@pd.tnic> <1516967135.2801.1.camel@redhat.com> <20180126115800.bvqrzik2f3hmmiah@pd.tnic> Organization: Red Hat Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Borislav Petkov píše v Pá 26. 01. 2018 v 12:58 +0100: > On Fri, Jan 26, 2018 at 12:45:35PM +0100, Petr Oros wrote: > > During time of facing the Spectre vulnerability and the requirement of handling > > different microcode updates, it has shown, that it would be useful to have > > additional information which microcode version was in BIOS, if the early-update > > routine will apply an update. > > Dmesg tells you if the update was applied or not. > > And if you really wanna know the old microcode revision, you can boot > with "dis_ucode_ldr" and do "grep microcode /proc/cpuinfo". > Ohh, yes, it is easy and fast. Mainly in time when new microcodes are released frequently and microcode can be early updated from initrd too. But what in production? Edit boot params, restart server, grep /proc/cpuinfo and restart again? Why i can not read it just from dmesg? Thanks, -Petr