Re: [PATCH drm-next 00/14] [RFC] DRM GPUVA Manager & Nouveau VM_BIND UAPI

[Danilo Krummrich <dakr@redhat.com>]

Hi Christian,

On 1/18/23 09:53, Christian König wrote:
> Am 18.01.23 um 07:12 schrieb Danilo Krummrich:
>> This patch series provides a new UAPI for the Nouveau driver in order to
>> support Vulkan features, such as sparse bindings and sparse residency.
>>
>> Furthermore, with the DRM GPUVA manager it provides a new DRM core 
>> feature to
>> keep track of GPU virtual address (VA) mappings in a more generic way.
>>
>> The DRM GPUVA manager is indented to help drivers implement 
>> userspace-manageable
>> GPU VA spaces in reference to the Vulkan API. In order to achieve this 
>> goal it
>> serves the following purposes in this context.
>>
>>      1) Provide a dedicated range allocator to track GPU VA 
>> allocations and
>>         mappings, making use of the drm_mm range allocator.
> 
> This means that the ranges are allocated by the kernel? If yes that's a 
> really really bad idea.

No, it's just for keeping track of the ranges userspace has allocated.

- Danilo

> 
> Regards,
> Christian.
> 
>>
>>      2) Generically connect GPU VA mappings to their backing buffers, in
>>         particular DRM GEM objects.
>>
>>      3) Provide a common implementation to perform more complex mapping
>>         operations on the GPU VA space. In particular splitting and 
>> merging
>>         of GPU VA mappings, e.g. for intersecting mapping requests or 
>> partial
>>         unmap requests.
>>
>> The new VM_BIND Nouveau UAPI build on top of the DRM GPUVA manager, 
>> itself
>> providing the following new interfaces.
>>
>>      1) Initialize a GPU VA space via the new 
>> DRM_IOCTL_NOUVEAU_VM_INIT ioctl
>>         for UMDs to specify the portion of VA space managed by the 
>> kernel and
>>         userspace, respectively.
>>
>>      2) Allocate and free a VA space region as well as bind and unbind 
>> memory
>>         to the GPUs VA space via the new DRM_IOCTL_NOUVEAU_VM_BIND ioctl.
>>
>>      3) Execute push buffers with the new DRM_IOCTL_NOUVEAU_EXEC ioctl.
>>
>> Both, DRM_IOCTL_NOUVEAU_VM_BIND and DRM_IOCTL_NOUVEAU_EXEC, make use 
>> of the DRM
>> scheduler to queue jobs and support asynchronous processing with DRM 
>> syncobjs
>> as synchronization mechanism.
>>
>> By default DRM_IOCTL_NOUVEAU_VM_BIND does synchronous processing,
>> DRM_IOCTL_NOUVEAU_EXEC supports asynchronous processing only.
>>
>> The new VM_BIND UAPI for Nouveau makes also use of drm_exec (execution 
>> context
>> for GEM buffers) by Christian König. Since the patch implementing 
>> drm_exec was
>> not yet merged into drm-next it is part of this series, as well as a 
>> small fix
>> for this patch, which was found while testing this series.
>>
>> This patch series is also available at [1].
>>
>> There is a Mesa NVK merge request by Dave Airlie [2] implementing the
>> corresponding userspace parts for this series.
>>
>> The Vulkan CTS test suite passes the sparse binding and sparse 
>> residency test
>> cases for the new UAPI together with Dave's Mesa work.
>>
>> There are also some test cases in the igt-gpu-tools project [3] for 
>> the new UAPI
>> and hence the DRM GPU VA manager. However, most of them are testing 
>> the DRM GPU
>> VA manager's logic through Nouveau's new UAPI and should be considered 
>> just as
>> helper for implementation.
>>
>> However, I absolutely intend to change those test cases to proper 
>> kunit test
>> cases for the DRM GPUVA manager, once and if we agree on it's 
>> usefulness and
>> design.
>>
>> [1] 
>> https://gitlab.freedesktop.org/nouvelles/kernel/-/tree/new-uapi-drm-next /
>>      https://gitlab.freedesktop.org/nouvelles/kernel/-/merge_requests/1
>> [2] https://gitlab.freedesktop.org/nouveau/mesa/-/merge_requests/150/
>> [3] 
>> https://gitlab.freedesktop.org/dakr/igt-gpu-tools/-/tree/wip_nouveau_vm_bind
>>
>> I also want to give credit to Dave Airlie, who contributed a lot of 
>> ideas to
>> this patch series.
>>
>> Christian König (1):
>>    drm: execution context for GEM buffers
>>
>> Danilo Krummrich (13):
>>    drm/exec: fix memory leak in drm_exec_prepare_obj()
>>    drm: manager to keep track of GPUs VA mappings
>>    drm: debugfs: provide infrastructure to dump a DRM GPU VA space
>>    drm/nouveau: new VM_BIND uapi interfaces
>>    drm/nouveau: get vmm via nouveau_cli_vmm()
>>    drm/nouveau: bo: initialize GEM GPU VA interface
>>    drm/nouveau: move usercopy helpers to nouveau_drv.h
>>    drm/nouveau: fence: fail to emit when fence context is killed
>>    drm/nouveau: chan: provide nouveau_channel_kill()
>>    drm/nouveau: nvkm/vmm: implement raw ops to manage uvmm
>>    drm/nouveau: implement uvmm for user mode bindings
>>    drm/nouveau: implement new VM_BIND UAPI
>>    drm/nouveau: debugfs: implement DRM GPU VA debugfs
>>
>>   Documentation/gpu/driver-uapi.rst             |   11 +
>>   Documentation/gpu/drm-mm.rst                  |   43 +
>>   drivers/gpu/drm/Kconfig                       |    6 +
>>   drivers/gpu/drm/Makefile                      |    3 +
>>   drivers/gpu/drm/amd/amdgpu/Kconfig            |    1 +
>>   drivers/gpu/drm/drm_debugfs.c                 |   56 +
>>   drivers/gpu/drm/drm_exec.c                    |  294 ++++
>>   drivers/gpu/drm/drm_gem.c                     |    3 +
>>   drivers/gpu/drm/drm_gpuva_mgr.c               | 1323 +++++++++++++++++
>>   drivers/gpu/drm/nouveau/Kbuild                |    3 +
>>   drivers/gpu/drm/nouveau/Kconfig               |    2 +
>>   drivers/gpu/drm/nouveau/include/nvif/if000c.h |   23 +-
>>   drivers/gpu/drm/nouveau/include/nvif/vmm.h    |   17 +-
>>   .../gpu/drm/nouveau/include/nvkm/subdev/mmu.h |   10 +
>>   drivers/gpu/drm/nouveau/nouveau_abi16.c       |   23 +
>>   drivers/gpu/drm/nouveau/nouveau_abi16.h       |    1 +
>>   drivers/gpu/drm/nouveau/nouveau_bo.c          |  152 +-
>>   drivers/gpu/drm/nouveau/nouveau_bo.h          |    2 +-
>>   drivers/gpu/drm/nouveau/nouveau_chan.c        |   16 +-
>>   drivers/gpu/drm/nouveau/nouveau_chan.h        |    1 +
>>   drivers/gpu/drm/nouveau/nouveau_debugfs.c     |   24 +
>>   drivers/gpu/drm/nouveau/nouveau_drm.c         |   25 +-
>>   drivers/gpu/drm/nouveau/nouveau_drv.h         |   92 +-
>>   drivers/gpu/drm/nouveau/nouveau_exec.c        |  310 ++++
>>   drivers/gpu/drm/nouveau/nouveau_exec.h        |   55 +
>>   drivers/gpu/drm/nouveau/nouveau_fence.c       |    7 +
>>   drivers/gpu/drm/nouveau/nouveau_fence.h       |    2 +-
>>   drivers/gpu/drm/nouveau/nouveau_gem.c         |   83 +-
>>   drivers/gpu/drm/nouveau/nouveau_mem.h         |    5 +
>>   drivers/gpu/drm/nouveau/nouveau_prime.c       |    2 +-
>>   drivers/gpu/drm/nouveau/nouveau_sched.c       |  780 ++++++++++
>>   drivers/gpu/drm/nouveau/nouveau_sched.h       |   98 ++
>>   drivers/gpu/drm/nouveau/nouveau_svm.c         |    2 +-
>>   drivers/gpu/drm/nouveau/nouveau_uvmm.c        |  575 +++++++
>>   drivers/gpu/drm/nouveau/nouveau_uvmm.h        |   68 +
>>   drivers/gpu/drm/nouveau/nouveau_vmm.c         |    4 +-
>>   drivers/gpu/drm/nouveau/nvif/vmm.c            |   73 +-
>>   .../gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.c    |  168 ++-
>>   .../gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.h    |    1 +
>>   drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c |   32 +-
>>   drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h |    3 +
>>   include/drm/drm_debugfs.h                     |   25 +
>>   include/drm/drm_drv.h                         |    6 +
>>   include/drm/drm_exec.h                        |  144 ++
>>   include/drm/drm_gem.h                         |   75 +
>>   include/drm/drm_gpuva_mgr.h                   |  527 +++++++
>>   include/uapi/drm/nouveau_drm.h                |  216 +++
>>   47 files changed, 5266 insertions(+), 126 deletions(-)
>>   create mode 100644 drivers/gpu/drm/drm_exec.c
>>   create mode 100644 drivers/gpu/drm/drm_gpuva_mgr.c
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_exec.c
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_exec.h
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_sched.c
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_sched.h
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_uvmm.c
>>   create mode 100644 drivers/gpu/drm/nouveau/nouveau_uvmm.h
>>   create mode 100644 include/drm/drm_exec.h
>>   create mode 100644 include/drm/drm_gpuva_mgr.h
>>
>>
>> base-commit: 0b45ac1170ea6416bc1d36798414c04870cd356d
>