[PATCH v4 0/2] Add sync object UAPI support to VirtIO-GPU driver

[Dmitry Osipenko]

We have multiple Vulkan context types that are awaiting for the addition
of the sync object DRM UAPI support to the VirtIO-GPU kernel driver:

 1. Venus context
 2. Native contexts (virtio-freedreno, virtio-intel, virtio-amdgpu)

Mesa core supports DRM sync object UAPI, providing Vulkan drivers with a
generic fencing implementation that we want to utilize.

This patch adds initial sync objects support. It creates fundament for a
further fencing improvements. Later on we will want to extend the VirtIO-GPU
fencing API with passing fence IDs to host for waiting, it will be a new
additional VirtIO-GPU IOCTL and more. Today we have several VirtIO-GPU context
drivers in works that require VirtIO-GPU to support sync objects UAPI.

The patch is heavily inspired by the sync object UAPI implementation of the
MSM driver.

Changelog:

v4: - Added r-b from Rob Clark to the "refactoring" patch.

    - Replaced for/while(ptr && itr) with if (ptr), like was suggested by
      Rob Clark.

    - Dropped NOWARN and NORETRY GFP flags and switched syncobj patch
      to use kvmalloc.

    - Removed unused variables from syncobj patch that were borrowed by
      accident from another (upcoming) patch after one of git rebases.

v3: - Switched to use dma_fence_unwrap_for_each(), like was suggested by
      Rob Clark.

    - Fixed missing dma_fence_put() in error code path that was spotted by
      Rob Clark.

    - Removed obsoleted comment to virtio_gpu_execbuffer_ioctl(), like was
      suggested by Rob Clark.

v2: - Fixed chain-fence context matching by making use of
      dma_fence_chain_contained().

    - Fixed potential uninitialized var usage in error code patch of
      parse_post_deps(). MSM driver had a similar issue that is fixed
      already in upstream.

    - Added new patch that refactors job submission code path. I found
      that it was very difficult to add a new/upcoming host-waits feature
      because of how variables are passed around the code, the virtgpu_ioctl.c
      also was growing to unmanageable size.

Dmitry Osipenko (2):
  drm/virtio: Refactor job submission code path
  drm/virtio: Support sync objects

 drivers/gpu/drm/virtio/Makefile         |   2 +-
 drivers/gpu/drm/virtio/virtgpu_drv.c    |   3 +-
 drivers/gpu/drm/virtio/virtgpu_drv.h    |   4 +
 drivers/gpu/drm/virtio/virtgpu_ioctl.c  | 182 ---------
 drivers/gpu/drm/virtio/virtgpu_submit.c | 521 ++++++++++++++++++++++++
 include/uapi/drm/virtgpu_drm.h          |  16 +-
 6 files changed, 543 insertions(+), 185 deletions(-)
 create mode 100644 drivers/gpu/drm/virtio/virtgpu_submit.c

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2.39.2