Re: [PATCH] x86/P2M: correct type use in p2m_put_gfn()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.02.2026 08:35, Roger Pau Monné wrote:
> On Tue, Feb 03, 2026 at 03:01:27PM +0100, Jan Beulich wrote:
>> Everywhere else gfn_t are passed into respective GFN locking macros: Do so
>> here as well.
>>
>> Amends: 819cdc5a7301 ("x86/p2m: re-arrange {,__}put_gfn()")
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Thanks.

>> ---
>> Easy to spot by adding ASSERT(!gfn_eq(g, INVALID_GFN)) to the respective
>> macros. While imo that should be a correct thing to do (as with
>> hypothetical split locks a valid GFN would really need passing in, in
>> order to be able to figure out which lock to use), we can't do so right
>> now: The lock is acquired ahead of respective checking in a number of
>> places, e.g. in p2m_get_gfn_type_access().
> 
> Could we convert those macros into static inlines?  It's dangerous to
> use macros like those when the parameters are dropped, as the
> parameter is not evaluated at all.

It is. Seeing how the header is used, converting may be possible. There's
one slight concern I'd have with doing so: It would move us one step
closer to giving the impression that the arguments passed are correct at
all use sites (while as long as they're entirely ignored, that's kind of
a hint that they may need checking). I can't point at it right now, but
I'm pretty sure I had come across at least one place where they're pretty
clearly wrong.

Jan