From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754082Ab2LKQsm (ORCPT ); Tue, 11 Dec 2012 11:48:42 -0500 Received: from terminus.zytor.com ([198.137.202.10]:59088 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753522Ab2LKQsk (ORCPT ); Tue, 11 Dec 2012 11:48:40 -0500 Message-ID: <50C763C2.5020603@zytor.com> Date: Tue, 11 Dec 2012 08:48:02 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Yinghai Lu CC: Borislav Petkov , "Yu, Fenghua" , "mingo@kernel.org" , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "hpa@linux.intel.com" , "linux-tip-commits@vger.kernel.org" Subject: Re: [tip:x86/microcode] x86/microcode_intel_early.c: Early update ucode on Intel's CPU References: <1354240068-9821-6-git-send-email-fenghua.yu@intel.com> <3E5A0FA7E9CA944F9D5414FEC6C71220470F154E@ORSMSX105.amr.corp.intel.com> <50C6AB63.9070008@zytor.com> <50C6D3DF.3030209@zytor.com> <20121211145716.GB8873@liondog.tnic> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/11/2012 08:46 AM, Yinghai Lu wrote: > On Tue, Dec 11, 2012 at 6:57 AM, Borislav Petkov wrote: >> On Mon, Dec 10, 2012 at 11:07:38PM -0800, Yinghai Lu wrote: >>> BTW, do we really need to update microcode so early? >> >> Yes we do. Normally ucode gets applied by the BIOS - this early approach >> is for those cases where OEMs don't release new BIOS anymore but we >> still need to apply a ucode patch as early as possible. > > but old bios with old ucode still work with some kind of previous kernel? > > Do we have case that system would not work with kernel if ucode is not > updated so early? > It's not about "not working"... it is about "if the microcode isn't loaded early we have to disable features." -hpa