Re: [PATCH for-4.19] ppc/riscv: fix arch_acquire_resource_check()

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

On Thu, May 02, 2024 at 10:46:12AM +0200, Oleksii wrote:
> On Tue, 2024-04-30 at 17:34 +0200, Roger Pau Monne wrote:
> > None of the implementations support set_foreign_p2m_entry() yet,
> > neither they
> > have a p2m walk in domain_relinquish_resources() in order to remove
> > the foreign
> > mappings from the p2m and thus drop the extra refcounts.
> > 
> > Adjust the arch helpers to return false and introduce a comment that
> > clearly
> > states it is not only taking extra refcounts that's needed, but also
> > dropping
> > them on domain teardown.
> I am okay with such adjustment for now as it is more safe and nothing
> will be missed during implementation of p2m, but I am curious how then
> Arm handles that, their implementation is also just returns true. ( I
> planned to have p2m implementation similar to Arm )

Arm does have an implementation of set_foreign_p2m_entry() and
domain_relinquish_resources() that handle foreign mappings correctly.

> 
> Anyway, based on that it safer for RISC-V:
> Reviewed-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

Thanks, Roger.