Re: [PATCH v7 3/8] xen/riscv: set up fixmap mappings

[oleksii.kurochko@xxxxxxxxx]

On Mon, 2024-09-16 at 08:32 +0200, Jan Beulich wrote:
> On 13.09.2024 17:57, Oleksii Kurochko wrote:
> > Set up fixmap mappings and the L0 page table for fixmap support.
> > 
> > {set, clear}_fixmap() is expected to be implemented using
> > map_pages_to_xen(), which, in turn, is only expected to use
> > arch_pmap_map().
> 
> Now you've left out what you actually mean to justify here: The
> exposure / direct access to xen_fixmap[]. I'd also suggest to
> drop "only" - I guess I used that in a reply to v6 to emphasize
> what I wanted to get across, but it makes not as much sense here.
> Instead adding "during early boot" at the end of the sentence may
> provide additional context.

Agree, it will be better to  return details:
   Modify the PTEs (xen_fixmap[]) directly in arch_pmap_map() instead
   of using set_fixmap() which is expected to be implemented using
   map_pages_to_xen(), which, in turn, is expected to use
   arch_pmap_map() during early boot, resulting in a loop.

Probably it would be better just:
   Modify xen_fixmap[] ...

> 
> > Define new macros in riscv/config.h for calculating
> > the FIXMAP_BASE address, including BOOT_FDT_VIRT_{START, SIZE},
> > XEN_VIRT_SIZE, and XEN_VIRT_END.
> > 
> > Update the check for Xen size in riscv/lds.S to use
> 
> Nit: xen.lds.S
> 
> > XEN_VIRT_SIZE instead of a hardcoded constant.
> > 
> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> 
> With the adjustments (again doable while committing)
That would be great.

> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Thanks a lot.

~ Oleksii