Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760112AbXLLTyS (ORCPT ); Wed, 12 Dec 2007 14:54:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754230AbXLLTyJ (ORCPT ); Wed, 12 Dec 2007 14:54:09 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:39811 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558AbXLLTyI (ORCPT ); Wed, 12 Dec 2007 14:54:08 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Andi Kleen Cc: Neil Horman , Yinghai Lu , Ben Woodard , Neil Horman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, hbabu@us.ibm.com, Andi Kleen , tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Subject: Re: [PATCH] kexec: force x86_64 arches to boot kdump kernels on boot cpu References: <20071211143910.GA10999@hmsreliant.think-freely.org> <20071211182254.GB10999@hmsreliant.think-freely.org> <20071211192434.GD10999@hmsreliant.think-freely.org> <86802c440712111151t29acd38kf9fac8e41743f3e4@mail.gmail.com> <20071211205955.GF10999@hmsreliant.think-freely.org> <20071212142132.GC4889@bingen.suse.de> <20071212155515.GA29735@hmsendeavour.rdu.redhat.com> <20071212160722.GD4889@bingen.suse.de> Date: Wed, 12 Dec 2007 12:43:34 -0700 In-Reply-To: <20071212160722.GD4889@bingen.suse.de> (Andi Kleen's message of "Wed, 12 Dec 2007 17:07:22 +0100") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1252 Lines: 31 Andi Kleen writes: > > It could enable the extended APIC IDs but not use them? In which case complaining is still correct (the BIOS was out of sync), enabling bit 17 is still correct and we are just in overkill mode. > Anyways I haven't got docs on that NV bridge so I might be wrong. This has everything to do with how AMD coherent hypertransport works and little if anything to do with how the NV bridge operated. Basically the NV bridge seems to be sending a standard hypertransport x86 legacy interrupt packet (that doesn't have any target information) and when that packet hits the coherent hypertransport domain it isn't being converted into whatever would send it to all cpus. ..... The real practical problem is if somehow the BIOS goofs up this way and it then decides to ask us to boot on one of these cpus with an extended apic id. We will hang in calibrate_delay. So far this only seems to happen in the kdump case but in theory the BIOS could be completely crazy. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/