Re: [PATCH 9/9] drm/tyr: add BO-related ioctls

[Daniel Almeida]

> On 1 Sep 2026, at 13:09, Ke Sun via B4 Relay <devnull+sunke.kylinos.cn@xxxxxxxxxx> wrote:
> 
> From: Alvin Sun <alvin.sun@xxxxxxxxx>
> 
> Expose buffer creation and BO mmap offset retrieval.
> 
> - BO_CREATE page-aligns the size and returns a handle with
>  write-combined mapping.
> - BO_MMAP_OFFSET provides the offset for the DRM generic mmap
>  path, rejecting NO_MMAP objects and non-zero pad.
> 
> Signed-off-by: Alvin Sun <alvin.sun@xxxxxxxxx>

Same comment as the previous patches, please write a few
more things here about why the changes are needed.

With that addressed, 

Reviewed-by: Daniel Almeida <daniel.almeida@xxxxxxxxxxxxx>

> ---
> drivers/gpu/drm/tyr/driver.rs |  2 ++
> drivers/gpu/drm/tyr/file.rs   | 70 +++++++++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/tyr/gem.rs    |  7 +++++
> 3 files changed, 79 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs
> index b3145526ada06..fc8d11c9ba1ca 100644
> --- a/drivers/gpu/drm/tyr/driver.rs
> +++ b/drivers/gpu/drm/tyr/driver.rs
> @@ -224,6 +224,8 @@ impl drm::Driver for TyrDrmDriver {
>         (PANTHOR_VM_DESTROY, drm_panthor_vm_destroy, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_destroy),
>         (PANTHOR_VM_BIND, drm_panthor_vm_bind, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_bind),
>         (PANTHOR_VM_GET_STATE, drm_panthor_vm_get_state, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_get_state),
> +        (PANTHOR_BO_CREATE, drm_panthor_bo_create, ioctl::RENDER_ALLOW, TyrDrmFileData::bo_create),
> +        (PANTHOR_BO_MMAP_OFFSET, drm_panthor_bo_mmap_offset, ioctl::RENDER_ALLOW, TyrDrmFileData::bo_mmap_offset),
>     }
> }
> 
> diff --git a/drivers/gpu/drm/tyr/file.rs b/drivers/gpu/drm/tyr/file.rs
> index 157bc40e1cac4..16abf2968299c 100644
> --- a/drivers/gpu/drm/tyr/file.rs
> +++ b/drivers/gpu/drm/tyr/file.rs
> @@ -252,6 +252,76 @@ pub(crate) fn vm_get_state(
>             Ok(0)
>         })
>     }
> +
> +    pub(crate) fn bo_create(
> +        ddev: &TyrDrmDevice<Registered>,
> +        _reg_data: &TyrDrmRegistrationData<'_>,
> +        bocreate: &mut uapi::drm_panthor_bo_create,
> +        file: &TyrDrmFile,
> +    ) -> Result<u32> {
> +        if bocreate.size == 0
> +            || bocreate.pad != 0
> +            || bocreate.flags & !uapi::drm_panthor_bo_flags_DRM_PANTHOR_BO_NO_MMAP != 0
> +            || bocreate.exclusive_vm_id != 0
> +        {
> +            dev_err!(
> +                ddev.as_ref(),
> +                "Invalid BO_CREATE params: size={}, pad={}, flags={:#x}, exclusive_vm_id={}\n",
> +                bocreate.size,
> +                bocreate.pad,
> +                bocreate.flags,
> +                bocreate.exclusive_vm_id
> +            );
> +            return Err(EINVAL);
> +        }
> +
> +        let size = usize::try_from(bocreate.size).map_err(|_| {
> +            dev_err!(
> +                ddev.as_ref(),
> +                "BO_CREATE size {:#x} too large\n",
> +                bocreate.size
> +            );
> +            EINVAL
> +        })?;
> +        let bo = crate::gem::new_object(ddev, size, bocreate.flags)?;
> +        bocreate.handle = bo.create_handle(file)?;
> +        bocreate.size = bo.size() as u64;
> +
> +        Ok(0)
> +    }
> +
> +    pub(crate) fn bo_mmap_offset(
> +        ddev: &TyrDrmDevice<Registered>,
> +        _reg_data: &TyrDrmRegistrationData<'_>,
> +        bommap: &mut uapi::drm_panthor_bo_mmap_offset,
> +        file: &TyrDrmFile,
> +    ) -> Result<u32> {
> +        if bommap.pad != 0 {
> +            dev_err!(
> +                ddev.as_ref(),
> +                "BO mmap offset pad not zero: {}\n",
> +                bommap.pad
> +            );
> +            return Err(EINVAL);
> +        }
> +
> +        let bo = crate::gem::lookup_handle(file, bommap.handle).inspect_err(|_| {
> +            dev_err!(ddev.as_ref(), "Invalid BO mmap handle: {}\n", bommap.handle);
> +        })?;
> +        if bo.create_flags() & uapi::drm_panthor_bo_flags_DRM_PANTHOR_BO_NO_MMAP != 0 {
> +            dev_err!(ddev.as_ref(), "BO mmap offset on NO_MMAP object\n");
> +            return Err(EPERM);
> +        }
> +        bommap.offset = bo.create_mmap_offset().inspect_err(|_| {
> +            dev_err!(
> +                ddev.as_ref(),
> +                "Failed to create mmap offset for handle {}\n",
> +                bommap.handle
> +            );
> +        })?;
> +
> +        Ok(0)
> +    }
> }
> 
> fn vm_bind_exec_op(vm: &Vm<'_>, file: &TyrDrmFile, op: &VmBindOp) -> Result {
> diff --git a/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs
> index d9ddcb287f52b..f404139f54f32 100644
> --- a/drivers/gpu/drm/tyr/gem.rs
> +++ b/drivers/gpu/drm/tyr/gem.rs
> @@ -38,6 +38,13 @@ pub(crate) struct BoData {
>     flags: u32,
> }
> 
> +impl BoData {
> +    /// Returns the flags the BO was created with.
> +    pub(crate) fn create_flags(&self) -> u32 {

I would prefer flags() instead of create_flags(), which reads a bit more like a constructor.

> +        self.flags
> +    }
> +}
> +
> /// Provides a way to pass arguments when creating BoData
> /// as required by the gem::DriverObject trait.
> pub(crate) struct BoCreateArgs {
> 
> -- 
> 2.43.0
> 
> 
>