Re: [PATCH v1 2/5] xen/riscv: implement maddr_to_virt()

[oleksii.kurochko@xxxxxxxxx]

On Thu, 2024-10-17 at 16:55 +0200, Jan Beulich wrote:
> On 16.10.2024 11:15, Oleksii Kurochko wrote:
> > --- a/xen/arch/riscv/include/asm/mm.h
> > +++ b/xen/arch/riscv/include/asm/mm.h
> > @@ -25,8 +25,12 @@
> >  
> >  static inline void *maddr_to_virt(paddr_t ma)
> >  {
> > -    BUG_ON("unimplemented");
> > -    return NULL;
> > +    /* Offset in the direct map, accounting for pdx compression */
> > +    unsigned long va_offset = maddr_to_directmapoff(ma);
> 
> Why the mentioning of PDX compression?
It was mentioned because if PDX will be enabled maddr_to_directmapoff()
will take into account PDX stuff.

>  At least right now it's unavailable
> for RISC-V afaics. Are there plans to change that any time soon?
At the moment, I don't have such plans, looking at available platform
there are no a lot of benefits of having PDX compression now.

Perhaps it would be good to add
BUILD_BUG_ON(IS_ENABLED(PDX_COMPRESSION)) for the places which should
be updated when CONFIG_PDX will be enabled.

~ Oleksii