Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754119AbeAKCFl (ORCPT + 1 other); Wed, 10 Jan 2018 21:05:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33934 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753826AbeAKCFi (ORCPT ); Wed, 10 Jan 2018 21:05:38 -0500 Date: Thu, 11 Jan 2018 10:05:32 +0800 From: Baoquan He To: linux-kernel@vger.kernel.org, fenghua.yu@intel.com, ebiederm@xmission.com, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com Cc: x86@kernel.org, rostedt@goodmis.org, jgross@suse.com, peterz@infradead.org, uobergfe@redhat.com, joro@8bytes.org Subject: Re: [RESEND PATCH 0/3] x86/apic/kexec: Enable legacy irq mode before jump to kexec/kdump kernel Message-ID: <20180111020532.GC6243@localhost.localdomain> References: <1515123732-28908-1-git-send-email-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515123732-28908-1-git-send-email-bhe@redhat.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 11 Jan 2018 02:05:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi all, PING! (Add Fenghua and Eric to this thread) On 01/05/18 at 11:42am, Baoquan He wrote: > On kvm guest, the latest kernel will always print warning during kdump kernel boots > as below. The reaons is the legacy irq mode is disabled before jump to kexec/kdump > kernel. So in setup_local_APIC(), the do { xxx } while (queued && max_loops > 0) > can't handle if pending irq exists in APIC IRR since LAPIC is disabled. It will > terminate the do while loop finally when max_loops overflows by subtraction. Then > WARN_ON(max_loops <= 0) is triggered. > > [ 0.001000] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/apic/apic.c:1467 setup_local_APIC+0x228/0x330 > [ 0.001000] Modules linked in: > [ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc5+ #3 > [ 0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc26 04/01/2014 > [ 0.001000] RIP: 0010:setup_local_APIC+0x228/0x330 > [ 0.001000] RSP: 0000:ffffffffb6e03eb8 EFLAGS: 00010286 > [ 0.001000] RAX: 0000009edb4c4d84 RBX: 0000000000000000 RCX: 00000000b099d800 > [ 0.001000] RDX: 0000009e00000000 RSI: 0000000000000000 RDI: 0000000000000810 > [ 0.001000] RBP: 0000000000000000 R08: ffffffffffffffff R09: 0000000000000001 > [ 0.001000] R10: ffff98ce6a801c00 R11: 0761076d072f0776 R12: 0000000000000001 > [ 0.001000] R13: 00000000000000f0 R14: 0000000000004000 R15: ffffffffffffc6ff > [ 0.001000] FS: 0000000000000000(0000) GS:ffff98ce6bc00000(0000) knlGS:0000000000000000 > [ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.001000] CR2: 00000000ffffffff CR3: 0000000022209000 CR4: 00000000000406b0 > [ 0.001000] Call Trace: > [ 0.001000] apic_bsp_setup+0x56/0x74 > [ 0.001000] x86_late_time_init+0x11/0x16 > [ 0.001000] start_kernel+0x3c9/0x486 > [ 0.001000] secondary_startup_64+0xa5/0xb0 > [ 0.001000] Code: 00 85 c9 74 2d 0f 31 c1 e1 0a 48 c1 e2 20 41 89 cf 4c 03 7c 24 08 48 09 d0 49 29 c7 4c 89 3c 24 48 83 3c 24 00 0f 8f 8f fe ff ff <0f> ff e9 10 ff ff ff 48 83 2c 24 01 eb e7 48 83 c4 18 5b 5d 41 > [ 0.001000] ---[ end trace b88e71b9a6ebebdd ]--- > [ 0.001000] masked ExtINT on CPU#0 > > With patch 2/3 applied, the above warning disappeared. And with patch 2/3 > applied, the issue mentioned in patch 1/3 can also be fixed because the LAPIC > has been set as ExtINT before jump to kdump kernel, while we had better set it > explicitly. Seems no reason not to enable legacy irq mode before jump to > kexec/kdump kernel, and can make it be consistent with normal kernel. > > Patch 3/3 is doing clean up, I am fine if people think it's unnecessary. > > > Baoquan He (3): > x86/apic: Set up through LAPIC on boot CPU's LINT0 if ioapic is > disabled > x86/apic/kexec: Enable legacy irq mode before jump to kexec/kdump > kernel > x86/apic: Clean up the names of legacy irq mode setting related > functions > > arch/x86/include/asm/apic.h | 2 +- > arch/x86/include/asm/io_apic.h | 6 +++--- > arch/x86/kernel/apic/apic.c | 13 +++++++------ > arch/x86/kernel/apic/io_apic.c | 25 ++++++++++++------------- > arch/x86/kernel/crash.c | 2 +- > arch/x86/kernel/machine_kexec_32.c | 15 +++++---------- > arch/x86/kernel/machine_kexec_64.c | 15 +++++---------- > arch/x86/kernel/reboot.c | 2 +- > arch/x86/kernel/x86_init.c | 2 +- > drivers/iommu/irq_remapping.c | 2 +- > 10 files changed, 37 insertions(+), 47 deletions(-) > > -- > 2.5.5 >