Re: [PATCH v5 04/12] xen/arm/irq: add handling for IRQs in the eSPI range

[Julien Grall <julien@xxxxxxx>]

Hi,

On 01/09/2025 15:42, Leonid Komarianskyi wrote:
> > > Taking into account that with CONFIG_GICV3_ESPI=n we should never have
> > > "irq" in eSPI range, do you really need this #ifdef? I think that
> > > ASSERT_UNREACHABLE in espi_to_desc() is sufficient guard.
> > >
> > > Also, IRQ line number belongs to eSPI range regardless of
> > > CONFIG_GICV3_ESPI,
> > > value, so in my opinion is_espi() should always return correct value for
> > > a given "irq".
> >    ... I agree with Volodymyr's suggestion for is_espi() to always return
> > correct value for a given "irq".
> I will fix that in V6.
I am not sure about this. If is_espi() is not returning false with 
CONFIG_GICV3_EPSI, then the compiler would not be able to optimize code 
like:
if (is_espi(...)) {
   return espi_to_desc(irq);
}

return &irq_desc[irq-NR_LOCAL_IRQS];

irq_to_desc() is called fairly often, so I would like to keep the code 
fairly optimized. An alternative would be to use #ifdef CONFIG_*. I 
don't like it, but it could be a compromise if Oleksandr and Volodymyr 
wants to push to remove #ifdef from CONFIG_IS_ESPI.
Cheers,

--
Julien Grall