On Wed, Jun 05, 2024 at 10:29:58AM +0100, Steven Price wrote:
> +void set_fixmap_io(enum fixed_addresses idx, phys_addr_t phys)
> +{
> + pgprot_t prot = FIXMAP_PAGE_IO;
> +
> + /*
> + * For now we consider all I/O as non-secure. For future
> + * filter the I/O base for setting appropriate permissions.
> + */
> + prot = __pgprot(pgprot_val(prot) | PROT_NS_SHARED);
> +
> + return __set_fixmap(idx, phys, prot);
> +}
In v2, Suzuki said that we want to keep this as a function rather than
just adding PROT_NS_SHARED to FIXMAP_PAGE_IO in case we want to change
this function in the future to allow protected MMIO.
https://lore.kernel.org/linux-arm-kernel/6ba1fd72-3bad-44ca-810d-572b70050772@xxxxxxx/
What I don't understand is that all the other MMIO cases just statically
assume unprotected/shard MMIO. Should we drop this patch here as well,
adjust FIXMAP_PAGE_IO and think about protected MMIO later when we
actually have to do device assignment?
--
Catalin
