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

[Sander Eikelenboom <linux@eikelenboom.it>]

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 ?

--
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)) {