[PATCH drm-misc-next v3 0/7] [RFC] DRM GPUVA Manager GPU-VM features

Danilo Krummrich
2023-09-09T16:27:39Z

So far the DRM GPUVA manager offers common infrastructure to track GPU VA
allocations and mappings, generically connect GPU VA mappings to their
backing buffers and perform more complex mapping operations on the GPU VA
space.

However, there are more design patterns commonly used by drivers, which
can potentially be generalized in order to make the DRM GPUVA manager
represent a basic GPU-VM implementation. In this context, this patch series
aims at generalizing the following elements.

1) Provide a common dma-resv for GEM objects not being used outside of
this GPU-VM.

2) Provide tracking of external GEM objects (GEM objects which are
shared with other GPU-VMs).

3) Provide functions to efficiently lock all GEM objects dma-resv the
GPU-VM contains mappings of.

4) Provide tracking of evicted GEM objects the GPU-VM contains mappings
of, such that validation of evicted GEM objects is accelerated.

5) Provide some convinience functions for common patterns.

The implementation introduces struct drm_gpuvm_bo, which serves as abstraction
combining a struct drm_gpuvm and struct drm_gem_object, similar to what
amdgpu does with struct amdgpu_bo_vm. While this adds a bit of complexity it
improves the efficiency of tracking external and evicted GEM objects.

This patch series also renames struct drm_gpuva_manager to struct drm_gpuvm
including corresponding functions. This way the GPUVA manager's structures align
better with the documentation of VM_BIND [1] and VM_BIND locking [2]. It also
provides a better foundation for the naming of data structures and functions
introduced for implementing the features of this patch series.

This patch series is also available at [3].

[1] Documentation/gpu/drm-vm-bind-async.rst
[2] Documentation/gpu/drm-vm-bind-locking.rst
[3] https://gitlab.freedesktop.org/nouvelles/kernel/-/commits/gpuvm-next

Changes in V2:
==============
- rename 'drm_gpuva_manager' -> 'drm_gpuvm' which generally leads to more
consistent naming
- properly separate commits (introduce common dma-resv, drm_gpuvm_bo
abstraction, etc.)
- remove maple tree for tracking external objects, use a list drm_gpuvm_bos
per drm_gpuvm instead
- rework dma-resv locking helpers (Thomas)
- add a locking helper for a given range of the VA space (Christian)
- make the GPUVA manager buildable as module, rather than drm_exec
builtin (Christian)

Changes in V3:
==============
- rename missing function and files (Boris)
- warn if vm_obj->obj != obj in drm_gpuva_link() (Boris)
- don't expose drm_gpuvm_bo_destroy() (Boris)
- unlink VM_BO from GEM in drm_gpuvm_bo_destroy() rather than
drm_gpuva_unlink() and link within drm_gpuvm_bo_obtain() to keep
drm_gpuvm_bo instances unique
- add internal locking to external and evicted object lists to support drivers
updating the VA space from within the fence signalling critical path (Boris)
- unlink external objects and evicted objects from the GPUVM's list in
drm_gpuvm_bo_destroy()
- add more documentation and fix some kernel doc issues

Danilo Krummrich (7):
drm/gpuvm: rename struct drm_gpuva_manager to struct drm_gpuvm
drm/gpuvm: allow building as module
drm/nouveau: uvmm: rename 'umgr' to 'base'
drm/gpuvm: common dma-resv per struct drm_gpuvm
drm/gpuvm: add an abstraction for a VM / BO combination
drm/gpuvm: generalize dma_resv/extobj handling and GEM validation
drm/nouveau: GPUVM dma-resv/extobj handling, GEM validation

drivers/gpu/drm/Kconfig | 7 +
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_debugfs.c | 16 +-
.../gpu/drm/{drm_gpuva_mgr.c => drm_gpuvm.c} | 1209 ++++++++++++++---
drivers/gpu/drm/nouveau/Kconfig | 1 +
drivers/gpu/drm/nouveau/nouveau_bo.c | 4 +-
drivers/gpu/drm/nouveau/nouveau_debugfs.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_exec.c | 52 +-
drivers/gpu/drm/nouveau/nouveau_exec.h | 4 -
drivers/gpu/drm/nouveau/nouveau_gem.c | 4 +-
drivers/gpu/drm/nouveau/nouveau_sched.h | 4 +-
drivers/gpu/drm/nouveau/nouveau_uvmm.c | 207 +--
drivers/gpu/drm/nouveau/nouveau_uvmm.h | 8 +-
include/drm/drm_debugfs.h | 6 +-
include/drm/drm_gem.h | 32 +-
include/drm/{drm_gpuva_mgr.h => drm_gpuvm.h} | 510 +++++--
16 files changed, 1605 insertions(+), 463 deletions(-)
rename drivers/gpu/drm/{drm_gpuva_mgr.c => drm_gpuvm.c} (51%)
rename include/drm/{drm_gpuva_mgr.h => drm_gpuvm.h} (53%)

base-commit: 6bd3d8da51ca1ec97c724016466606aec7739b9f
--
2.41.0