Re: [Xen-devel] [Bugfix] x86/apic: Fix xen IRQ allocation failure caused by commit b81975eade8c

[Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>]

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();
>> +    }
> 
> 
> Is there a specific reason that this cannot run in all cases?
> 
> What I am asking is why are we doing a special case here? The description
> at the top implied that we were just missing an call to
> setup_IO_APIC.. 
Hi Konrad,
        I'm not very familiar with Xen IRQ yet, so I just enabled the
code to create irqdomains for IOAPICs and keep other part as is. I will
try to check whether we could enable other part all together:)
Regards!
Gerry

> 
>>  
>> -    apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
>>      for_each_ioapic(ioapic)
>>              BUG_ON(mp_irqdomain_create(ioapic));
>> -
>> -    /*
>> -         * Set up IO-APIC IRQ routing.
>> -         */
>> -    x86_init.mpparse.setup_ioapic_ids();
>> -
>> -    sync_Arb_IDs();
>>      setup_IO_APIC_irqs();
>> -    init_IO_APIC_traps();
>> -    if (nr_legacy_irqs())
>> -            check_timer();
>> -
>>      ioapic_initialized = 1;
>> +
>> +    if (!xen_smp) {
>> +            init_IO_APIC_traps();
>> +            if (nr_legacy_irqs())
>> +                    check_timer();
>> +    }
>>  }
>>  
>>  /*
>> 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@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel