From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941294AbcKOBXA (ORCPT ); Mon, 14 Nov 2016 20:23:00 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:17868 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932174AbcKOBW6 (ORCPT ); Mon, 14 Nov 2016 20:22:58 -0500 Subject: Re: [PATCH] x86/cpuid: Deal with broken firmware once more To: "M. Vefa Bicakci" References: <20161102122557.qs4rl6mb7n7l7j7p@linutronix.de> <24e69019-60d0-29e7-e31f-c6f00f9ed98a@brocade.com> <58e229e2-91f4-a97f-1b9f-089f48ef994a@brocade.com> <86609338-2b45-ed7e-fb07-99421e43a2f1@brocade.com> <49fe8cc5-0f0f-6cac-7a5c-803e81f5667d@runbox.com> <68840c0b-44c9-ddd8-bfab-f4fd8bacbaf0@oracle.com> <41978b7b-2880-4ea5-14c3-7185422261e7@runbox.com> Cc: "Charles (Chas) Williams" , Thomas Gleixner , Sebastian Andrzej Siewior , "x86@kernel.org" , LKML , Peter Zijlstra , Borislav Petkov , David Vrabel , Juergen Gross , xen-devel From: Boris Ostrovsky Message-ID: <96419776-022d-63f9-84c4-7426101f4657@oracle.com> Date: Mon, 14 Nov 2016 20:21:22 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <41978b7b-2880-4ea5-14c3-7185422261e7@runbox.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/13/2016 06:42 PM, M. Vefa Bicakci wrote: > I found out that my domU kernels invoke the 'apic_disable' function > because CONFIG_X86_MPPARSE was not enabled in my kernel configuration, > which would cause the 'smp_found_config' bit to be unset at boot-up. smp_found_config is not the problem, it is usually zero for Xen PV guests. What is the problem is that because of your particular config selection acpi_mps_check() fails (with the error message that you mention below) and that leads to X86_FEATURE_APIC being cleared. And then we indeed switch to APIC noop and things go south after that. -boris > > This would cause 'init_apic_mappings' to call 'apic_disable', which > would cause Xen's 'apic' ops structure pointer to be replaced with the > no-op APIC ops structure's pointer. > > The use of the no-op APIC ops structure would in turn cause invalid > virtual CPU package identifiers to be generated. Invalid CPU package > identifiers would in turn cause the RAPL module to produce a kernel oops > due to potentially missing error handling. > > It looks like I have been ignoring the following kernel warning which I > should have noticed a long time ago: > > MPS support code is not built-in. > Using acpi=off or acpi=noirq or pci=noacpi may have problem > > To all on this e-mail thread, I learned a bit through this exercise, but > I have also taken a lot of everyone's time and created quite a bit of > e-mail traffic because of a kernel configuration issue on my end. > > My apologies. > > Vefa >