From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933944AbcKIOWk (ORCPT ); Wed, 9 Nov 2016 09:22:40 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:58260 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933532AbcKIOWf (ORCPT ); Wed, 9 Nov 2016 09:22:35 -0500 Date: Wed, 9 Nov 2016 15:22:21 +0100 From: Sebastian Andrzej Siewior To: Borislav Petkov Cc: "Luck, Tony" , linux-kernel@vger.kernel.org, rt@linutronix.de, linux-edac@vger.kernel.org, x86@kernel.org, Thomas Gleixner Subject: Re: [PATCH 22/25] x86/mcheck: Do the init in one place Message-ID: <20161109142221.3r6xwhkxbckuv3bh@linutronix.de> References: <20161103145021.28528-1-bigeasy@linutronix.de> <20161103145021.28528-23-bigeasy@linutronix.de> <20161107184532.xj6wzdjlzwhshcmf@pd.tnic> <20161107185524.GA2536@intel.com> <20161107201224.7xazmhgm7bogkrw5@pd.tnic> <20161108092302.wraci5m2cxqozlew@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20161108092302.wraci5m2cxqozlew@pd.tnic> User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016-11-08 10:23:02 [+0100], Borislav Petkov wrote: > On Mon, Nov 07, 2016 at 09:12:24PM +0100, Borislav Petkov wrote: > > On Mon, Nov 07, 2016 at 10:55:24AM -0800, Luck, Tony wrote: > > > I don't think that helps as much as you'd like it to help (at > > > least on Intel). A broadcast machine check that finds the boot > > > CPU has set CR4[MCE]=1 is still going to end up in reset if any > > > other CPU still has CR4[MCE]=0 > > > > By leaving/moving the setting of CR4 earlier on all cores, we'll > > at least make the possible window for such potential resets a lot > > smaller... > > ... and in general, I'm still unsure about *why* we need this change for > hotplug. bigeasy, can you please clarify first? I want to get rid of non-symmetrical part and the arch hook which should be part of the hp notifier itself. I wouldn't be too much afraid about the when point in time when the notifier runs: It is the *first* notifier that will be invoked on the target CPU. This is only a few lines after the old hook. Nothing else long delaying should be invoked. > Thanks. Sebastian