Re: [PATCH v5 08/14] gpu: nova-core: gsp: Create rmargs

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

On Mon Oct 13, 2025 at 3:20 PM JST, Alistair Popple wrote:
> Initialise the GSP resource manager arguments (rmargs) which provide
> initialisation parameters to the GSP firmware during boot. The rmargs
> structure contains arguments to configure the GSP message/command queue
> location.
>
> These are mapped for coherent DMA and added to the libos data structure
> for access when booting GSP.
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
>
> ---
>
> Changes for v5:
>  - Derive Zeroable trait
>
> Changes for v2:
>  - Rebased on Alex's latest series
> ---
>  drivers/gpu/nova-core/gsp.rs                  |  16 +++
>  drivers/gpu/nova-core/gsp/cmdq.rs             |  24 +++-
>  drivers/gpu/nova-core/gsp/fw.rs               |  60 ++++++++
>  .../gpu/nova-core/gsp/fw/r570_144/bindings.rs | 132 ------------------

Mmm, looks like we are removing bindings. Can we not add them in the
first place? :)

>  4 files changed, 97 insertions(+), 135 deletions(-)
>
> diff --git a/drivers/gpu/nova-core/gsp.rs b/drivers/gpu/nova-core/gsp.rs
> index 1d472c5fad7a..58b595b8badd 100644
> --- a/drivers/gpu/nova-core/gsp.rs
> +++ b/drivers/gpu/nova-core/gsp.rs
> @@ -19,6 +19,7 @@
>  mod fw;
>  
>  use fw::LibosMemoryRegionInitArgument;
> +use fw::GspArgumentsCached;
>  
>  pub(crate) mod cmdq;
>  
> @@ -36,6 +37,7 @@ pub(crate) struct Gsp {
>      logintr: LogBuffer,
>      logrm: LogBuffer,
>      pub(crate) cmdq: Cmdq,
> +    rmargs: CoherentAllocation<GspArgumentsCached>,
>  }
>  
>  #[repr(C)]
> @@ -117,12 +119,26 @@ pub(crate) fn new(pdev: &pci::Device<device::Bound>) -> Result<impl PinInit<Self
>  
>          // Creates its own PTE array.
>          let cmdq = Cmdq::new(dev)?;
> +        let rmargs = CoherentAllocation::<GspArgumentsCached>::alloc_coherent(

Let's add a space between the declaration of `cmdq` and `rmargs`.

> +            dev,
> +            1,
> +            GFP_KERNEL | __GFP_ZERO,
> +        )?;
> +        dma_write!(libos[3] = LibosMemoryRegionInitArgument::new("RMARGS", &rmargs)?)?;
> +
> +        dma_write!(
> +            rmargs[0] = fw::GspArgumentsCached::new(
> +                fw::MessageQueueInitArguments::new(&cmdq),
> +                fw::GspSrInitArguments::new()
> +            )
> +        )?;
>  
>          Ok(try_pin_init!(Self {
>              libos,
>              loginit,
>              logintr,
>              logrm,
> +            rmargs,
>              cmdq,
>          }))
>      }
> diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
> index 3f8cb7a35922..da074a2ed0d9 100644
> --- a/drivers/gpu/nova-core/gsp/cmdq.rs
> +++ b/drivers/gpu/nova-core/gsp/cmdq.rs
> @@ -6,7 +6,7 @@
>  
>  use kernel::alloc::flags::GFP_KERNEL;
>  use kernel::device;
> -use kernel::dma::CoherentAllocation;
> +use kernel::dma::{CoherentAllocation, DmaAddress};
>  use kernel::dma_write;
>  use kernel::io::poll::read_poll_timeout;
>  use kernel::prelude::*;
> @@ -247,10 +247,25 @@ pub(crate) struct Cmdq {
>      dev: ARef<device::Device>,
>      seq: u32,
>      gsp_mem: DmaGspMem,
> -    pub _nr_ptes: u32,

We probably shouldn't have introduced this unused member in the first place.

>  }
>  
>  impl Cmdq {
> +    /// Offset of the data after the PTEs.
> +    const POST_PTE_OFFSET: usize = core::mem::offset_of!(GspMem, cpuq);
> +
> +    /// Offset of command queue ring buffer.
> +    pub(crate) const CMDQ_OFFSET: usize = core::mem::offset_of!(GspMem, cpuq)
> +        + core::mem::offset_of!(Msgq, msgq)
> +        - Self::POST_PTE_OFFSET;
> +
> +    /// Offset of message queue ring buffer.
> +    pub(crate) const STATQ_OFFSET: usize = core::mem::offset_of!(GspMem, gspq)
> +        + core::mem::offset_of!(Msgq, msgq)
> +        - Self::POST_PTE_OFFSET;
> +
> +    /// Number of page table entries for the GSP shared region.
> +    pub(crate) const NUM_PTES: usize = size_of::<GspMem>() >> GSP_PAGE_SHIFT;
> +
>      pub(crate) fn new(dev: &device::Device<device::Bound>) -> Result<Cmdq> {
>          let gsp_mem = DmaGspMem::new(dev)?;
>          let nr_ptes = size_of::<GspMem>() >> GSP_PAGE_SHIFT;
> @@ -260,7 +275,6 @@ pub(crate) fn new(dev: &device::Device<device::Bound>) -> Result<Cmdq> {
>              dev: dev.into(),
>              seq: 0,
>              gsp_mem,
> -            _nr_ptes: nr_ptes as u32,
>          })
>      }
>  
> @@ -490,4 +504,8 @@ pub(crate) fn receive_msg_from_gsp<M: MessageFromGsp, R>(
>              .advance_cpu_read_ptr(msg_header.length().div_ceil(GSP_PAGE_SIZE as u32));
>          result
>      }
> +
> +    pub(crate) fn dma_handle(&self) -> DmaAddress {
> +        self.gsp_mem.0.dma_handle()
> +    }
>  }
> diff --git a/drivers/gpu/nova-core/gsp/fw.rs b/drivers/gpu/nova-core/gsp/fw.rs
> index a2ce570ddfaf..70abda1c2af8 100644
> --- a/drivers/gpu/nova-core/gsp/fw.rs
> +++ b/drivers/gpu/nova-core/gsp/fw.rs
> @@ -16,6 +16,7 @@
>  
>  use crate::firmware::gsp::GspFirmware;
>  use crate::gpu::Chipset;
> +use crate::gsp::cmdq::Cmdq;
>  use crate::gsp::FbLayout;
>  use crate::gsp::GSP_PAGE_SIZE;
>  
> @@ -483,3 +484,62 @@ unsafe impl AsBytes for GspMsgElement {}
>  // SAFETY: This struct only contains integer types for which all bit patterns
>  // are valid.
>  unsafe impl FromBytes for GspMsgElement {}
> +
> +#[repr(transparent)]
> +pub(crate) struct GspArgumentsCached(bindings::GSP_ARGUMENTS_CACHED);
> +
> +impl GspArgumentsCached {
> +    pub(crate) fn new(
> +        queue_arguments: MessageQueueInitArguments,
> +        sr_arguments: GspSrInitArguments,
> +    ) -> Self {
> +        Self(bindings::GSP_ARGUMENTS_CACHED {
> +            messageQueueInitArguments: queue_arguments.0,
> +            srInitArguments: sr_arguments.0,
> +            bDmemStack: 1,
> +            ..Default::default()
> +        })
> +    }
> +}
> +
> +impl From<GspArgumentsCached> for bindings::GSP_ARGUMENTS_CACHED {
> +    fn from(value: GspArgumentsCached) -> Self {
> +        value.0
> +    }
> +}

This `From` impl seems unneeded?