Re: [PATCH] x86/IO-APIC: fix setting of destinations

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 11/19/2015 04:46 AM, Jan Beulich wrote:
> In commit a85da715cf ("x86/IO-APIC: adjust setting of destinations") I
> made a pretty blatant mistake: get_apic_id() can be used there only
> when running APICs in physical mode. For both flat and clustered modes
> the change was wrong, causing different kinds of boot problems on
> affected systems. Don't revert that change though, but use TARGET_CPUS
> (equaling cpu_online_map, and with there only being a single online CPU
> fulfilling the original commits intention).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> --- a/xen/arch/x86/io_apic.c
> +++ b/xen/arch/x86/io_apic.c
> @@ -1039,7 +1039,7 @@ static void __init setup_IO_APIC_irqs(vo
>                   disable_8259A_irq(irq_to_desc(irq));
>   
>               desc = irq_to_desc(irq);
> -            SET_DEST(entry, logical, get_apic_id());
> +            SET_DEST(entry, logical, cpu_mask_to_apicid(TARGET_CPUS));
>               spin_lock_irqsave(&ioapic_lock, flags);
>               __ioapic_write_entry(apic, pin, 0, entry);
>               set_native_irq_info(irq, TARGET_CPUS);


Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

(One of our systems started failing and I bisected it yesterday to 
a85da715c but didn't get to actually debug it. Now I don't need to).

-boris