Re: [PATCH v3 4/8] pdx: allow per-arch optimization of PDX conversion helpers

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Jul 29, 2025 at 03:54:24PM +0100, Andrew Cooper wrote:
> On 24/07/2025 12:04 pm, Roger Pau Monne wrote:
> > diff --git a/xen/arch/arm/include/asm/Makefile 
> > b/xen/arch/arm/include/asm/Makefile
> > index 4565baca6a4d..cec13c889dab 100644
> > --- a/xen/arch/arm/include/asm/Makefile
> > +++ b/xen/arch/arm/include/asm/Makefile
> > @@ -5,6 +5,7 @@ generic-y += hardirq.h
> >  generic-y += iocap.h
> >  generic-y += irq-dt.h
> >  generic-y += paging.h
> > +generic-y += pdx.h
> >  generic-y += percpu.h
> >  generic-y += random.h
> >  generic-y += softirq.h
> 
> Please could I talk you into using __has_include__, as I'm slowly trying
> to purge asm-generic.
> 
> > diff --git a/xen/include/xen/pdx.h b/xen/include/xen/pdx.h
> > index 10153da98bf1..91fc32370f21 100644
> > --- a/xen/include/xen/pdx.h
> > +++ b/xen/include/xen/pdx.h
> > @@ -159,6 +159,14 @@ static inline paddr_t directmapoff_to_maddr(unsigned 
> > long offset)
> >  
> >  #endif /* CONFIG_PDX_MASK_COMPRESSION */
> >  
> > +/*
> > + * Allow each architecture to define it's (possibly optimized) versions of 
> > the
> > + * translation functions.
> > + *
> > + * Do not use _xlate suffixed functions, always use the non _xlate 
> > variants.
> > + */
> > +#include <asm/pdx.h>
> > +
> 
> You want:
> 
> #if __has_include__(<asm/pdx.h>)
> # include <asm/pdx.h>
> #else
> 
> // common defaults.
> 
> #endif
> 
> here.  This lets you implement the x86 special case only, and keeps all
> the common logic in one file.

Sure, I wasn't aware of this functionality.

Thanks, Roger.