Re: [PATCH v7 04/12] xen/arm/irq: add handling for IRQs in the eSPI range

[Julien Grall <julien@xxxxxxx>]

On 05/09/2025 11:05, Leonid Komarianskyi wrote:
> On 05.09.25 10:10, Julien Grall wrote:
> > Hi Leonid,
> >
> > On 04/09/2025 21:01, Leonid Komarianskyi wrote:
> > > diff --git a/xen/arch/arm/include/asm/irq.h b/xen/arch/arm/include/
> > > asm/irq.h
> > > index 5bc6475eb4..2ff2d07d6d 100644
> > > --- a/xen/arch/arm/include/asm/irq.h
> > > +++ b/xen/arch/arm/include/asm/irq.h
> > > @@ -32,6 +32,10 @@ struct arch_irq_desc {
> > >    #define SPI_MAX_INTID   1019
> > >    #define LPI_OFFSET      8192
> > > +#define ESPI_BASE_INTID 4096
> > > +#define ESPI_MAX_INTID  5119
> > > +#define NR_ESPI_IRQS    1024
> > > +
> > >    /* LPIs are always numbered starting at 8192, so 0 is a good invalid
> > > case. */
> > >    #define INVALID_LPI     0
> > > @@ -39,7 +43,12 @@ struct arch_irq_desc {
> > >    #define INVALID_IRQ     1023
> > >    extern const unsigned int nr_irqs;
> > > +#ifdef CONFIG_GICV3_ESPI
> > > +/* This will cover the eSPI range, to allow asignmant of eSPIs to
> > > domains. */
> > Typo: s/asignmant/assignment/
> >
> > [...]
> >
> > > Unless INTIDs from the eSPI
> > > + * range are mistakenly defined in Xen DTS when the appropriate
> > > config is
> > > + * disabled, this function will not be reached because is_espi will
> > > return
> > > + * false for non-eSPI INTIDs.
> > I am still confused with this paragraph. How is this function can be
> > reached if it is compiled out? Surely, if the DT is misconfigured, we
> > should get an error when trying to route the interrupt. No? If so, can
> > you point me to that code?
> >
> > Cheers,
> Oh, sorry, the second part of the comment is redundant with the current
> implementation. It was correct when the function had an implementation
> and returned NULL. The correct comment is:
>
> Defined as a prototype as it should not be called if
> CONFIG_GICV3_ESPI=n. Without CONFIG_GICV3_ESPI, the additional 1024 IRQ
> descriptors will not be defined, and thus, they cannot be used.
>
> Should I prepare V8 with the comment fix, or can this be corrected on
> commit?
I should be able to update it while committing.

Cheers,

--
Julien Grall