Re: [Xen-devel] About GSI and IRQ?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 21.03.14 at 11:28, hanyandong <hanyandong@xxxxxxxxx> wrote:
> static int apic_pin_2_gsi_irq(int apic, int pin)
> {
>     int idx;
> 
>     if (apic < 0)
>        return -EINVAL;
> 
>     idx = find_irq_entry(apic, pin, mp_INT);
> 
>     return idx >= 0 ? pin_2_irq(idx, apic, pin)
>                     : apic_gsi_base(apic) + pin;
> }
> 
> what make me most confued is the function name of "apic_pin_2_gsi_irq", is 
> the returned value  a GSI or a IRQ?
> when to use GSI? when to use IRQ?

With you having quoted the function above already, I don't think
there's much to say here: If it can (valid index into mp_irqs[]), it
returns an IRQ, else it returns a GSI. For PCI IRQs the two would
always match (i.e. the distinction is only relevant for the other
MP_BUS_* types).

Jan


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