Re: [PATCH v3] gpu: nova-core: gsp: fix undefined behavior in command queue code

[Alexandre Courbot]

On Thu Mar 26, 2026 at 2:43 PM JST, Alexandre Courbot wrote:
> `driver_read_area` and `driver_write_area` are internal methods that
> return slices containing the area of the command queue buffer that the
> driver has exclusive read or write access, respectively.
>
> While their returned value is correct and safe to use, internally they
> temporarily create a reference to the whole command-buffer slice,
> including GSP-owned regions. These regions can change without notice,
> and thus creating a slice to them, even if never accessed, is undefined
> behavior.
>
> Fix this by rewriting these methods to use pointer projections in order
> to create slices to valid regions only. It should eventually be replaced
> by `IoView` and `IoSlice` once they land.
>
> Fixes: 75f6b1de8133 ("gpu: nova-core: gsp: Add GSP command queue bindings and handling")
> Reported-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> Closes: https://lore.kernel.org/all/DH47AVPEKN06.3BERUSJIB4M1R@xxxxxxxxxx/
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

I'd like to merge this before -rc6 is tagged and drm-rust-next is closed
if possible (i.e. this weekend) - so acks/reviews would be very welcome
if there are no outstanding issues! :)