Re: [PATCH v9 05/23] gpu: nova-core: gsp: Expose total physical VRAM end from FB region info

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

On Wed Mar 11, 2026 at 9:39 AM JST, Joel Fernandes wrote:
> Add `total_fb_end()` to `GspStaticConfigInfo` that computes the exclusive end
> address of the highest valid FB region covering both usable and GSP-reserved
> areas.
>
> This allows callers to know the full physical VRAM extent, not just the
> allocatable portion.
>
> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
> ---
>  drivers/gpu/nova-core/gsp/commands.rs    |  6 ++++++
>  drivers/gpu/nova-core/gsp/fw/commands.rs | 19 +++++++++++++++++++
>  2 files changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
> index 8d5780d9cace..389d215098c6 100644
> --- a/drivers/gpu/nova-core/gsp/commands.rs
> +++ b/drivers/gpu/nova-core/gsp/commands.rs
> @@ -193,6 +193,9 @@ pub(crate) struct GetGspStaticInfoReply {
>      /// Usable FB (VRAM) region for driver memory allocation.
>      #[expect(dead_code)]
>      pub(crate) usable_fb_region: Range<u64>,
> +    /// End of VRAM.
> +    #[expect(dead_code)]
> +    pub(crate) total_fb_end: u64,
>  }
>  
>  impl MessageFromGsp for GetGspStaticInfoReply {
> @@ -206,9 +209,12 @@ fn read(
>      ) -> Result<Self, Self::InitError> {
>          let (base, size) = msg.first_usable_fb_region().ok_or(ENODEV)?;
>  
> +        let total_fb_end = msg.total_fb_end().ok_or(ENODEV)?;
> +
>          Ok(GetGspStaticInfoReply {
>              gpu_name: msg.gpu_name_str(),
>              usable_fb_region: base..base.saturating_add(size),
> +            total_fb_end,
>          })
>      }
>  }
> diff --git a/drivers/gpu/nova-core/gsp/fw/commands.rs b/drivers/gpu/nova-core/gsp/fw/commands.rs
> index cef86cab8a12..acaf92cd6735 100644
> --- a/drivers/gpu/nova-core/gsp/fw/commands.rs
> +++ b/drivers/gpu/nova-core/gsp/fw/commands.rs
> @@ -147,6 +147,25 @@ pub(crate) fn first_usable_fb_region(&self) -> Option<(u64, u64)> {
>          }
>          None
>      }
> +
> +    /// Compute the end of physical VRAM from all FB regions.
> +    pub(crate) fn total_fb_end(&self) -> Option<u64> {
> +        let fb_info = &self.0.fbRegionInfoParams;
> +        let mut max_end: Option<u64> = None;
> +        for i in 0..fb_info.numFBRegions.into_safe_cast() {
> +            if let Some(reg) = fb_info.fbRegion.get(i) {
> +                if reg.limit < reg.base {
> +                    continue;
> +                }

This is basically a repeat of the code of the previous patch. Let's
implement an iterator over the FB memory regions (that filters out
invalid regions) that we can leverage in both places so we don't need to
repeat ourselves.