Re: [PATCH v3 11/12] gpu: nova-core: align LibosMemoryRegionInitArgument size to page size

["Alexandre Courbot" <acourbot@nvidia.com>]

On Tue Dec 9, 2025 at 8:18 AM JST, Timur Tabi wrote:
> On Turing and GA100 (i.e. the versions that use Libos v2), GSP-RM insists
> that the 'size' parameter of the LibosMemoryRegionInitArgument struct be
> aligned to 4KB.  The logging buffers are already aligned to that size, so
> only the GSP_ARGUMENTS_CACHED struct needs to be adjusted.  Make that
> adjustment by adding padding to the end of the struct.
>
> Signed-off-by: Timur Tabi <ttabi@nvidia.com>
> ---
>  drivers/gpu/nova-core/gsp/fw.rs | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
> index abffd6beec65..6f53df0f6f3d 100644
> --- a/drivers/gpu/nova-core/gsp/fw.rs
> +++ b/drivers/gpu/nova-core/gsp/fw.rs
> @@ -889,17 +889,27 @@ unsafe impl AsBytes for GspMsgElement {}
>  unsafe impl FromBytes for GspMsgElement {}
>  
>  /// Arguments for GSP startup.
> -#[repr(transparent)]
> -pub(crate) struct GspArgumentsCached(bindings::GSP_ARGUMENTS_CACHED);
> +///
> +/// On Turing and GA100, the entries in the `LibosMemoryRegionInitArgument`
> +/// must all be a multiple of GSP_PAGE_SIZE in size, so add padding to force it
> +/// to that size.
> +#[repr(C)]
> +pub(crate) struct GspArgumentsCached(
> +    bindings::GSP_ARGUMENTS_CACHED,
> +    [u8; GSP_PAGE_SIZE - core::mem::size_of::<bindings::GSP_ARGUMENTS_CACHED>()],
> +);
>  
>  impl GspArgumentsCached {
>      /// Creates the arguments for starting the GSP up using `cmdq` as its command queue.
>      pub(crate) fn new(cmdq: &Cmdq) -> Self {
> -        Self(bindings::GSP_ARGUMENTS_CACHED {
> -            messageQueueInitArguments: MessageQueueInitArguments::new(cmdq).0,
> -            bDmemStack: 1,
> -            ..Default::default()
> -        })
> +        Self(
> +            bindings::GSP_ARGUMENTS_CACHED {
> +                messageQueueInitArguments: MessageQueueInitArguments::new(cmdq).0,
> +                bDmemStack: 1,
> +                ..Default::default()
> +            },
> +            [0u8; GSP_PAGE_SIZE - core::mem::size_of::<bindings::GSP_ARGUMENTS_CACHED>()]

You can use `Zeroable::zeroed()` instead of this last complex line.