From mboxrd@z Thu Jan 1 00:00:00 1970 From: jiang.liu@linux.intel.com (Jiang Liu) Date: Thu, 08 Jan 2015 14:36:38 +0800 Subject: [Bugfix] x86/apic: Fix xen IRQ allocation failure caused by commit b81975eade8c In-Reply-To: <20150107154416.GB30955@l.oracle.com> References: <1420611244-25624-1-git-send-email-jiang.liu@linux.intel.com> <20150107145050.GC30457@l.oracle.com> <54AD52D0.5050303@linux.intel.com> <20150107154416.GB30955@l.oracle.com> Message-ID: <54AE2576.5020209@linux.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2015/1/7 23:44, Konrad Rzeszutek Wilk wrote: > On Wed, Jan 07, 2015 at 11:37:52PM +0800, Jiang Liu wrote: >> On 2015/1/7 22:50, Konrad Rzeszutek Wilk wrote: >>> On Wed, Jan 07, 2015 at 02:13:49PM +0800, Jiang Liu wrote: >>>> Commit b81975eade8c ("x86, irq: Clean up irqdomain transition code") >>>> breaks xen IRQ allocation because xen_smp_prepare_cpus() doesn't invoke >>>> setup_IO_APIC(), so no irqdomains created for IOAPICs and >>>> mp_map_pin_to_irq() fails at the very beginning. >>>> --- a/arch/x86/kernel/apic/io_apic.c >>>> +++ b/arch/x86/kernel/apic/io_apic.c >>>> @@ -2369,31 +2369,29 @@ static void ioapic_destroy_irqdomain(int idx) >>>> ioapics[idx].pin_info = NULL; >>>> } >>>> >>>> -void __init setup_IO_APIC(void) >>>> +void __init setup_IO_APIC(bool xen_smp) >>>> { >>>> int ioapic; >>>> >>>> - /* >>>> - * calling enable_IO_APIC() is moved to setup_local_APIC for BP >>>> - */ >>>> - io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL; >>>> + if (!xen_smp) { >>>> + apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n"); >>>> + io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL; >>>> + >>>> + /* Set up IO-APIC IRQ routing. */ >>>> + x86_init.mpparse.setup_ioapic_ids(); >>>> + sync_Arb_IDs(); >>>> + } Hi Konrad, Enabling above code for Xen dom0 will cause following warning because it writes a special value to ICR register. [ 3.394981] ------------[ cut here ]------------ [ 3.394985] WARNING: CPU: 0 PID: 1 at arch/x86/xen/enlighten.c:968 xen_apic_write+0x15/0x20() [ 3.394988] Modules linked in: [ 3.394991] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc3+ #5 [ 3.394993] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A03 09/17/2013 [ 3.394996] 00000000000003c8 ffff88003056bdd8 ffffffff817611bb 00000000000003c8 [ 3.395000] 0000000000000000 ffff88003056be18 ffffffff8106f4ea 0000000000000008 [ 3.395004] ffffffff81fc1120 ffff880030561348 000000000000a108 000000000000a101 [ 3.395008] Call Trace: [ 3.395012] [] dump_stack+0x4f/0x6c [ 3.395015] [] warn_slowpath_common+0xaa/0xd0 [ 3.395018] [] warn_slowpath_null+0x15/0x20 [ 3.395021] [] xen_apic_write+0x15/0x20 [ 3.395026] [] sync_Arb_IDs+0x84/0x86 [ 3.395029] [] setup_IO_APIC+0x7f/0x8e3 [ 3.395033] [] ? trace_hardirqs_on+0xd/0x10 [ 3.395036] [] ? _raw_spin_unlock_irqrestore+0x8a/0xa0 [ 3.395040] [] xen_smp_prepare_cpus+0x5d/0x184 [ 3.395044] [] kernel_init_freeable+0x149/0x293 [ 3.395047] [] ? kernel_init+0x9/0xf0 [ 3.395049] [] ? rest_init+0xd0/0xd0 [ 3.395052] [] kernel_init+0x9/0xf0 [ 3.395054] [] ret_from_fork+0x7c/0xb0 [ 3.395057] [] ? rest_init+0xd0/0xd0 [ 3.395066] ---[ end trace 7c4371c8ba33d5d0 ]--- >>>> ioapic_initialized = 1; >>>> + >>>> + if (!xen_smp) { >>>> + init_IO_APIC_traps(); >>>> + if (nr_legacy_irqs()) >>>> + check_timer(); >>>> + } >>>> } And enabling above code causes Xen dom0 reboots. Haven't test HVM and PV kernel yet. So seems we still need special treatment for xen here. Regards! Gerry >>>> >>>> /* >>>> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c >>>> index 4c071aeb8417..7eb0283901fa 100644 >>>> --- a/arch/x86/xen/smp.c >>>> +++ b/arch/x86/xen/smp.c >>>> @@ -326,7 +326,10 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus) >>>> >>>> xen_raw_printk(m); >>>> panic(m); >>>> + } else { >>>> + setup_IO_APIC(true); >>>> } >>>> + >>>> xen_init_lock_cpu(0); >>>> >>>> smp_store_boot_cpu_info(); >>>> -- >>>> 1.7.10.4 >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>> the body of a message to majordomo at vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> Please read the FAQ at http://www.tux.org/lkml/ >>> > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >