From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [Qemu-devel] [PATCH 1/2] target-i386: disable LINT0 after reset Date: Wed, 16 Sep 2015 08:47:56 +0200 Message-ID: <1442386076.26770.8.camel@redhat.com> References: <1428881529-29459-1-git-send-email-namit@cs.technion.ac.il> <1428881529-29459-2-git-send-email-namit@cs.technion.ac.il> <1442351982.23936.157.camel@redhat.com> <55F8FCD2.2000003@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Alex Williamson , Nadav Amit , pbonzini@redhat.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, bsd@redhat.com, avi.kivity@gmail.com To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752076AbbIPGsA (ORCPT ); Wed, 16 Sep 2015 02:48:00 -0400 In-Reply-To: <55F8FCD2.2000003@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mi, 2015-09-16 at 07:23 +0200, Jan Kiszka wrote: > On 2015-09-15 23:19, Alex Williamson wrote: > > On Mon, 2015-04-13 at 02:32 +0300, Nadav Amit wrote: > >> Due to old Seabios bug, QEMU reenable LINT0 after reset. This bug is long gone > >> and therefore this hack is no longer needed. Since it violates the > >> specifications, it is removed. > >> > >> Signed-off-by: Nadav Amit > >> --- > >> hw/intc/apic_common.c | 9 --------- > >> 1 file changed, 9 deletions(-) > > > > Please see bug: https://bugs.launchpad.net/qemu/+bug/1488363 > > > > Is this bug perhaps not as long gone as we thought, or is there > > something else going on here? Thanks, > > I would say, someone needs to check if the SeaBIOS line that is supposed > to enable LINT0 is actually executed on one of the broken systems and, > if not, why not. There is only one reason (beside miscompiling seabios with CONFIG_QEMU=n) why seabios would skip acpi initialization, and that is apic not being present according to cpuid: cpuid(1, &eax, &ebx, &ecx, &cpuid_features); if (eax < 1 || !(cpuid_features & CPUID_APIC)) { // No apic - only the main cpu is present. https://www.kraxel.org/cgit/seabios/tree/src/fw/smp.c#n79 cheers, Gerd PS: coreboot tripped over this too, fixed just a few days ago. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52083) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zc6Vh-0004SA-2C for qemu-devel@nongnu.org; Wed, 16 Sep 2015 02:48:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zc6Vc-0000co-T7 for qemu-devel@nongnu.org; Wed, 16 Sep 2015 02:48:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50591) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zc6Vc-0000cd-NU for qemu-devel@nongnu.org; Wed, 16 Sep 2015 02:48:00 -0400 Message-ID: <1442386076.26770.8.camel@redhat.com> From: Gerd Hoffmann Date: Wed, 16 Sep 2015 08:47:56 +0200 In-Reply-To: <55F8FCD2.2000003@siemens.com> References: <1428881529-29459-1-git-send-email-namit@cs.technion.ac.il> <1428881529-29459-2-git-send-email-namit@cs.technion.ac.il> <1442351982.23936.157.camel@redhat.com> <55F8FCD2.2000003@siemens.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/2] target-i386: disable LINT0 after reset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: kvm@vger.kernel.org, Nadav Amit , Alex Williamson , qemu-devel@nongnu.org, bsd@redhat.com, avi.kivity@gmail.com, pbonzini@redhat.com On Mi, 2015-09-16 at 07:23 +0200, Jan Kiszka wrote: > On 2015-09-15 23:19, Alex Williamson wrote: > > On Mon, 2015-04-13 at 02:32 +0300, Nadav Amit wrote: > >> Due to old Seabios bug, QEMU reenable LINT0 after reset. This bug is long gone > >> and therefore this hack is no longer needed. Since it violates the > >> specifications, it is removed. > >> > >> Signed-off-by: Nadav Amit > >> --- > >> hw/intc/apic_common.c | 9 --------- > >> 1 file changed, 9 deletions(-) > > > > Please see bug: https://bugs.launchpad.net/qemu/+bug/1488363 > > > > Is this bug perhaps not as long gone as we thought, or is there > > something else going on here? Thanks, > > I would say, someone needs to check if the SeaBIOS line that is supposed > to enable LINT0 is actually executed on one of the broken systems and, > if not, why not. There is only one reason (beside miscompiling seabios with CONFIG_QEMU=n) why seabios would skip acpi initialization, and that is apic not being present according to cpuid: cpuid(1, &eax, &ebx, &ecx, &cpuid_features); if (eax < 1 || !(cpuid_features & CPUID_APIC)) { // No apic - only the main cpu is present. https://www.kraxel.org/cgit/seabios/tree/src/fw/smp.c#n79 cheers, Gerd PS: coreboot tripped over this too, fixed just a few days ago.