From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933578AbcKJOVr (ORCPT ); Thu, 10 Nov 2016 09:21:47 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:39340 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933335AbcKJOVq (ORCPT ); Thu, 10 Nov 2016 09:21:46 -0500 Subject: Re: 4.8.2 not booting in 32-bit VM without I/O-APIC To: tglx@linutronix.de References: Cc: Michal Necasek , prarit@redhat.com, ville.syrjala@linux.intel.com, frank.mehnert@oracle.com, knut.osmundsen@oracle.com, linux-kernel@vger.kernel.org From: Michael Thayer Organization: ORACLE Deutschland B.V. und Co. KG Message-ID: <9d85a95e-332c-db85-8e62-2015de8ecb85@oracle.com> Date: Thu, 10 Nov 2016 15:21:28 +0100 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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit 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 Hello, On 03.11.2016 21:02, Michal Necasek wrote: > Sorry for the delay. I can confirm that the problem is fixed in > 4.9.0-rc3 and prefill_possible_map no longer crashes (as it did in > 4.9.0-rc2). Thank you! > > Just a side question, is the previous fix in commit ff8560512b > (x86/boot/smp: Don't try to poke disabled/non-existent APIC) actually > still required or would the no-op APIC driver take care of it? Sorry for the delay too (holiday-related). I tested 4.9.0rc4 on a 32-bit VirtualBox virtual machine without I/O-APIC and can confirm that it now boots. Since I am at it, the OHCI timer wheel-related problems are also no longer reproducible. Regards and thanks, Michael > > Regards, Michal > > ----- Original Message ----- From: tglx@linutronix.de To: > michal.necasek@oracle.com Cc: prarit@redhat.com, > ville.syrjala@linux.intel.com, michael.thayer@oracle.com, > knut.osmundsen@oracle.com, frank.mehnert@oracle.com, > linux-kernel@vger.kernel.org Sent: Friday, October 28, 2016 9:37:31 > PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna > Subject: Re: 4.8.2 not booting in 32-bit VM without I/O-APIC > > On Fri, 28 Oct 2016, Thomas Gleixner wrote: > >> On Fri, 28 Oct 2016, Michal Necasek wrote: >>> >>> Sorry if I wasn't clear. No, it doesn't work for us. The >>> ff8560512b8d commit fixes the APIC poking on machines where there >>> is no local APIC available (and thus fixes the committer's >>> machine), but it doesn't work in our case, where there is a local >>> APIC but no I/O APIC, no ACPI MADT, and no MP tables. >> >>> In other words, for us boot_cpu_has(X86_FEATURE_APIC) is true but >>> the APIC has not been set up yet because init_apic_mappings() >>> hasn't been run. > > Right. That mapping setup is an utter trainwreck as we do it from > multiple places, but there is no reason why we can't move it before > the call to prefill_possible_map(). > > Thanks, > > tglx > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index > bbfbca5fea0c..b59fdba3cbdf 100644 --- a/arch/x86/kernel/setup.c +++ > b/arch/x86/kernel/setup.c @@ -1221,11 +1221,13 @@ void __init > setup_arch(char **cmdline_p) */ get_smp_config(); > > + /* Make sure apic is mapped before prefill_possible_map() */ + > init_apic_mappings(); + prefill_possible_map(); > > init_cpu_to_node(); > > - init_apic_mappings(); io_apic_init_mappings(); > > kvm_guest_init(); > -- Michael Thayer | VirtualBox engineer ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt ORACLE Deutschland B.V. & Co. KG Hauptverwaltung: Riesstraße 25, D-80992 München Registergericht: Amtsgericht München, HRA 95603 Komplementärin: ORACLE Deutschland Verwaltung B.V. Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister der Handelskammer Midden-Nederland, Nr. 30143697 Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher