Re: [PATCH] xen/mm: Introduce per-arch pte_attr_t type for PTE flags

[Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>]

On 1/9/25 3:15 AM, Jan Beulich wrote:
> On 31.12.2024 19:27, Shawn Anastasio wrote:
>> Xen's memory management APIs map_pages_to_xen, modify_xen_mappings,
>> set_fixmap, ioremap_attr, and __vmap all use an unsigned int to
>> represent architecture-dependent page table entry flags. This assumption
>> does not work on PPC/radix where some flags go past 32-bits, so
>> introduce the pte_attr_t type to allow architectures to opt in to larger
>> types to store PTE flags.
>>
>> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>> Signed-off-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>
> 
> As iirc Andrew had indicated when suggesting this, what you say for PPC is
> true for x86 as well. Yet still we get around with unsigned int. Hence I
> think the change needs describing differently.
> 

I see what you mean -- I'll reword this to correctly reflect that the
change is not strictly necessary to accomodate architectures with
greater than 32-bit pte flags.

> Jan

Thanks,
Shawn