Re: [PATCH v3] [Bugfix] x86/apic: Fix xen IRQ allocation failure caused by commit b81975eade8c

[Jiang Liu <jiang.liu@linux.intel.com>]

On 2015/1/14 20:23, Sander Eikelenboom wrote:
> 
> Wednesday, January 14, 2015, 4:09:35 AM, you 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.
> 
>> So move creating of IOAPIC irqdomains from setup_IO_APIC() into
>> arch_early_ioapic_init().
> 
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
>> Reported-and-tested-by: Sander Eikelenboom <linux@eikelenboom.it>
>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
> Thanks Gerry !
> Will you send (a backport) to stable for 3.17 and 3.18 when 
> it's applied to -tip ?
Sure, will do it once it reaches mainstream kernel.

> 
> --
> Sander
> 
>> ---
>>  arch/x86/kernel/apic/io_apic.c |   13 +++++++------
>>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
>> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
>> index 3f5f60406ab1..1117c84cefe4 100644
>> --- a/arch/x86/kernel/apic/io_apic.c
>> +++ b/arch/x86/kernel/apic/io_apic.c
>> @@ -245,6 +245,8 @@ static void free_ioapic_saved_registers(int idx)
>>         ioapics[idx].saved_registers = NULL;
>>  }
>>  
>> +static int mp_irqdomain_create(int ioapic);
>> +
>>  int __init arch_early_ioapic_init(void)
>>  {
>>         struct irq_cfg *cfg;
>> @@ -253,8 +255,10 @@ int __init arch_early_ioapic_init(void)
>>         if (!nr_legacy_irqs())
>>                 io_apic_irqs = ~0UL;
>>  
>> -       for_each_ioapic(i)
>> +       for_each_ioapic(i) {
>> +               BUG_ON(mp_irqdomain_create(i));
>>                 alloc_ioapic_saved_registers(i);
>> +       }
>>  
>>         /*
>>          * For legacy IRQ's, start with assigning irq0 to irq15 to
>> @@ -2371,16 +2375,12 @@ static void ioapic_destroy_irqdomain(int idx)
>>  
>>  void __init setup_IO_APIC(void)
>>  {
>> -       int ioapic;
>> -
>>         /*
>>          * calling enable_IO_APIC() is moved to setup_local_APIC for BP
>>          */
>>         io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL;
>>  
>>         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.
>> @@ -2929,7 +2929,8 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base,
>>         /*
>>          * If mp_register_ioapic() is called during early boot stage when
>>          * walking ACPI/SFI/DT tables, it's too early to create irqdomain,
>> -        * we are still using bootmem allocator. So delay it to setup_IO_APIC().
>> +        * we are still using bootmem allocator.So delay it to
>> +        * arch_early_ioapic_init().
>>          */
>>         if (hotplug) {
>>                 if (mp_irqdomain_create(idx)) {
>