Re: [PATCH v2 0/8] DRM Rust abstractions and Nova

[Daniel Vetter <daniel.vetter@ffwll.ch>]

On Wed, Jun 19, 2024 at 01:31:36AM +0200, Danilo Krummrich wrote:
> This patch series implements some basic DRM Rust abstractions and a stub
> implementation of the Nova GPU driver.
> 
> Nova is intended to be developed upstream, starting out with just a stub driver
> to lift some initial required infrastructure upstream. A more detailed
> explanation can be found in [1].
> 
> This patch series is based on the "Device / Driver and PCI Rust abstractions"
> series [2].
> 
> The DRM bits can also be found in [3] and the Nova bits in [4].
> 
> Changes in v2:
> ==============
> - split up the DRM device / driver abstractions in three separate commits
> - separate `struct drm_device` abstraction in a separte source file more
>   cleanly
> - switch `struct drm_driver` and `struct file_operations` to 'static const'
>   allocations
> - implement `Registration::new_foreign_owned` (using `Devres`), such that we
>   don't need to keep the `Registration` alive on the Rust side, but
>   automatically revoke it on device unbind
> - add missing DRM driver features (Rob)
> - use `module_pci_driver!` macro in Nova
> - use a const sized `pci::Bar` in Nova
> - increase the total amount of Documentation, rephrase some safety comments and
>   commit messages for less ambiguity
> - fix compilation issues with some documentation example
> 
> [1] https://lore.kernel.org/dri-devel/Zfsj0_tb-0-tNrJy@cassiopeiae/T/#u
> [2] Reply to this mail titled "Device / Driver and PCI Rust abstractions".
> [3] https://gitlab.freedesktop.org/drm/misc/kernel/-/tree/topic/rust-drm
> [4] https://gitlab.freedesktop.org/drm/nova/-/tree/nova-next

Ok finally stopped dragging my feet on this, went through my old comments,
looked at stuff again, and wrote some replies.

I think all but the question around type safety for drm_driver->features
can be sorted out post-merge, when we have a driver that needs it. The
feature flags stuff I think essentially makes the current abstraction
unsafe, and you can blow up when constructing a new drm::Device instance
if you're creative enough I think.

Cheers, Sima

> 
> Asahi Lina (4):
>   rust: drm: ioctl: Add DRM ioctl abstraction
>   rust: Add a Sealed trait
>   rust: drm: file: Add File abstraction
>   rust: drm: gem: Add GEM object abstraction
> 
> Danilo Krummrich (4):
>   rust: drm: add driver abstractions
>   rust: drm: add device abstraction
>   rust: drm: add DRM driver registration
>   nova: add initial driver stub
> 
>  MAINTAINERS                     |  10 +
>  drivers/gpu/drm/Kconfig         |   2 +
>  drivers/gpu/drm/Makefile        |   1 +
>  drivers/gpu/drm/nova/Kconfig    |  12 +
>  drivers/gpu/drm/nova/Makefile   |   3 +
>  drivers/gpu/drm/nova/driver.rs  |  85 +++++++
>  drivers/gpu/drm/nova/file.rs    |  70 ++++++
>  drivers/gpu/drm/nova/gem.rs     |  50 ++++
>  drivers/gpu/drm/nova/gpu.rs     | 173 ++++++++++++++
>  drivers/gpu/drm/nova/nova.rs    |  18 ++
>  include/uapi/drm/nova_drm.h     | 101 ++++++++
>  rust/bindings/bindings_helper.h |   5 +
>  rust/helpers.c                  |  23 ++
>  rust/kernel/drm/device.rs       | 182 ++++++++++++++
>  rust/kernel/drm/drv.rs          | 199 ++++++++++++++++
>  rust/kernel/drm/file.rs         | 116 +++++++++
>  rust/kernel/drm/gem/mod.rs      | 409 ++++++++++++++++++++++++++++++++
>  rust/kernel/drm/ioctl.rs        | 153 ++++++++++++
>  rust/kernel/drm/mod.rs          |   9 +
>  rust/kernel/lib.rs              |   7 +
>  rust/uapi/uapi_helper.h         |   2 +
>  21 files changed, 1630 insertions(+)
>  create mode 100644 drivers/gpu/drm/nova/Kconfig
>  create mode 100644 drivers/gpu/drm/nova/Makefile
>  create mode 100644 drivers/gpu/drm/nova/driver.rs
>  create mode 100644 drivers/gpu/drm/nova/file.rs
>  create mode 100644 drivers/gpu/drm/nova/gem.rs
>  create mode 100644 drivers/gpu/drm/nova/gpu.rs
>  create mode 100644 drivers/gpu/drm/nova/nova.rs
>  create mode 100644 include/uapi/drm/nova_drm.h
>  create mode 100644 rust/kernel/drm/device.rs
>  create mode 100644 rust/kernel/drm/drv.rs
>  create mode 100644 rust/kernel/drm/file.rs
>  create mode 100644 rust/kernel/drm/gem/mod.rs
>  create mode 100644 rust/kernel/drm/ioctl.rs
>  create mode 100644 rust/kernel/drm/mod.rs
> 
> 
> base-commit: 6646240d29b11de3177f71ff777d0ae683c32623
> -- 
> 2.45.1
> 

-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch