From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756198Ab2JVUdo (ORCPT ); Mon, 22 Oct 2012 16:33:44 -0400 Received: from terminus.zytor.com ([198.137.202.10]:36023 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756142Ab2JVUdn (ORCPT ); Mon, 22 Oct 2012 16:33:43 -0400 Message-ID: <5085AD7D.106@zytor.com> Date: Mon, 22 Oct 2012 13:33:01 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: "Eric W. Biederman" CC: HATAYAMA Daisuke , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org, mingo@elte.hu, tglx@linutronix.de, len.brown@intel.com, fenghua.yu@intel.com, vgoyal@redhat.com, grant.likely@secretlab.ca, rob.herring@calxeda.com Subject: Re: [PATCH v1 2/2] x86, apic: Disable BSP if boot cpu is AP References: <20121016043357.20003.5885.stgit@localhost6.localdomain6> <20121016043528.20003.601.stgit@localhost6.localdomain6> <873916i88t.fsf@xmission.com> <5085A9A8.5020004@zytor.com> <87fw56fduo.fsf@xmission.com> In-Reply-To: <87fw56fduo.fsf@xmission.com> X-Enigmail-Version: 1.4.3 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/2012 01:31 PM, Eric W. Biederman wrote: >> >> IIRC Fenghua experimented with that and it didn't work. Not all BIOSes >> use that bit to determine BSP-ness. > > What does a BIOS have to do with anything? > > The practical issue here is does an INIT IPI cause the cpu to go into > startup-ipi-wait or to start booting at 4G-16 bytes. > > For dealing with BIOSen we may still need to use the bootstrap processor > for firmware calls, cpu suspend, and other firmware weirdness, but that > should all be completely orthogonal to the behavior to what happens > when an INIT IPI is sent to the cpu. > > The only firmware problem I can imagine having is cpu virtualization > bug. > The whole problem is that some BIOSes go wonky after receiving an INIT (as in INIT-SIPI-SIPI) to the BSP. -hpa From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from terminus.zytor.com ([2001:1868:205::10] helo=mail.zytor.com) by casper.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TQOgt-0004jT-S4 for kexec@lists.infradead.org; Mon, 22 Oct 2012 20:33:41 +0000 Message-ID: <5085AD7D.106@zytor.com> Date: Mon, 22 Oct 2012 13:33:01 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH v1 2/2] x86, apic: Disable BSP if boot cpu is AP References: <20121016043357.20003.5885.stgit@localhost6.localdomain6> <20121016043528.20003.601.stgit@localhost6.localdomain6> <873916i88t.fsf@xmission.com> <5085A9A8.5020004@zytor.com> <87fw56fduo.fsf@xmission.com> In-Reply-To: <87fw56fduo.fsf@xmission.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: "Eric W. Biederman" Cc: len.brown@intel.com, fenghua.yu@intel.com, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, rob.herring@calxeda.com, grant.likely@secretlab.ca, HATAYAMA Daisuke , tglx@linutronix.de, mingo@elte.hu, vgoyal@redhat.com On 10/22/2012 01:31 PM, Eric W. Biederman wrote: >> >> IIRC Fenghua experimented with that and it didn't work. Not all BIOSes >> use that bit to determine BSP-ness. > > What does a BIOS have to do with anything? > > The practical issue here is does an INIT IPI cause the cpu to go into > startup-ipi-wait or to start booting at 4G-16 bytes. > > For dealing with BIOSen we may still need to use the bootstrap processor > for firmware calls, cpu suspend, and other firmware weirdness, but that > should all be completely orthogonal to the behavior to what happens > when an INIT IPI is sent to the cpu. > > The only firmware problem I can imagine having is cpu virtualization > bug. > The whole problem is that some BIOSes go wonky after receiving an INIT (as in INIT-SIPI-SIPI) to the BSP. -hpa _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec