[PATCH v6 00/20] drm/i915/vm_bind: Add VM_BIND functionality

[Zanoni, Paulo R]

On Mon, 2022-11-07 at 00:51 -0800, Niranjana Vishwanathapura wrote:
> DRM_I915_GEM_VM_BIND/UNBIND ioctls allows UMD to bind/unbind GEM
> buffer objects (BOs) or sections of a BOs at specified GPU virtual
> addresses on a specified address space (VM). Multiple mappings can map
> to the same physical pages of an object (aliasing). These mappings (also
> referred to as persistent mappings) will be persistent across multiple
> GPU submissions (execbuf calls) issued by the UMD, without user having
> to provide a list of all required mappings during each submission (as
> required by older execbuf mode).
> 
> This patch series support VM_BIND version 1, as described by the param
> I915_PARAM_VM_BIND_VERSION.
> 
> Add new execbuf3 ioctl (I915_GEM_EXECBUFFER3) which only works in
> vm_bind mode. The vm_bind mode only works with this new execbuf3 ioctl.
> The new execbuf3 ioctl will not have any execlist support and all the
> legacy support like relocations etc., are removed.
> 
> NOTEs:
> * It is based on below VM_BIND design+uapi rfc.
>   Documentation/gpu/rfc/i915_vm_bind.rst

Hi

One difference for execbuf3 that I noticed that is not mentioned in the
RFC document is that we now don't have a way to signal
EXEC_OBJECT_WRITE. When looking at the Kernel code, some there are some
pieces that check for this flag:

- there's code that deals with frontbuffer rendering 
- there's code that deals with fences
- there's code that prevents self-modifying batches
- another that seems related to waiting for objects

Are there any new rules regarding frontbuffer rendering when we use
execbuf3? Any other behavior changes related to the other places that
we should expect when using execbuf3?

Thanks,
Paulo

> 
> * The IGT RFC series is posted as,
>   [PATCH i-g-t v5 0/12] vm_bind: Add VM_BIND validation support
> 
> v2: Address various review comments
> v3: Address review comments and other fixes
> v4: Remove vm_unbind out fence uapi which is not supported yet,
>     replace vm->vm_bind_mode check with i915_gem_vm_is_vm_bind_mode()
> v5: Render kernel-doc, use PIN_NOEVICT, limit vm_bind support to
>     non-recoverable faults
> v6: Rebased, minor fixes, add reserved fields to drm_i915_gem_vm_bind,
>     add new patch for async vm_unbind support
> 
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
> 
> Niranjana Vishwanathapura (20):
>   drm/i915/vm_bind: Expose vm lookup function
>   drm/i915/vm_bind: Add __i915_sw_fence_await_reservation()
>   drm/i915/vm_bind: Expose i915_gem_object_max_page_size()
>   drm/i915/vm_bind: Add support to create persistent vma
>   drm/i915/vm_bind: Implement bind and unbind of object
>   drm/i915/vm_bind: Support for VM private BOs
>   drm/i915/vm_bind: Add support to handle object evictions
>   drm/i915/vm_bind: Support persistent vma activeness tracking
>   drm/i915/vm_bind: Add out fence support
>   drm/i915/vm_bind: Abstract out common execbuf functions
>   drm/i915/vm_bind: Use common execbuf functions in execbuf path
>   drm/i915/vm_bind: Implement I915_GEM_EXECBUFFER3 ioctl
>   drm/i915/vm_bind: Update i915_vma_verify_bind_complete()
>   drm/i915/vm_bind: Expose i915_request_await_bind()
>   drm/i915/vm_bind: Handle persistent vmas in execbuf3
>   drm/i915/vm_bind: userptr dma-resv changes
>   drm/i915/vm_bind: Limit vm_bind mode to non-recoverable contexts
>   drm/i915/vm_bind: Add uapi for user to enable vm_bind_mode
>   drm/i915/vm_bind: Render VM_BIND documentation
>   drm/i915/vm_bind: Async vm_unbind support
> 
>  Documentation/gpu/i915.rst                    |  78 +-
>  drivers/gpu/drm/i915/Makefile                 |   3 +
>  drivers/gpu/drm/i915/gem/i915_gem_context.c   |  43 +-
>  drivers/gpu/drm/i915/gem/i915_gem_context.h   |  17 +
>  drivers/gpu/drm/i915/gem/i915_gem_create.c    |  72 +-
>  drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    |   6 +
>  .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 516 +----------
>  .../gpu/drm/i915/gem/i915_gem_execbuffer3.c   | 871 ++++++++++++++++++
>  .../drm/i915/gem/i915_gem_execbuffer_common.c | 666 +++++++++++++
>  .../drm/i915/gem/i915_gem_execbuffer_common.h |  74 ++
>  drivers/gpu/drm/i915/gem/i915_gem_ioctls.h    |   2 +
>  drivers/gpu/drm/i915/gem/i915_gem_object.c    |   3 +
>  drivers/gpu/drm/i915/gem/i915_gem_object.h    |   2 +
>  .../gpu/drm/i915/gem/i915_gem_object_types.h  |   6 +
>  drivers/gpu/drm/i915/gem/i915_gem_userptr.c   |  19 +
>  drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h   |  30 +
>  .../drm/i915/gem/i915_gem_vm_bind_object.c    | 449 +++++++++
>  drivers/gpu/drm/i915/gt/intel_gtt.c           |  17 +
>  drivers/gpu/drm/i915/gt/intel_gtt.h           |  21 +
>  drivers/gpu/drm/i915/i915_driver.c            |   4 +
>  drivers/gpu/drm/i915/i915_drv.h               |   2 +
>  drivers/gpu/drm/i915/i915_gem_gtt.c           |  39 +
>  drivers/gpu/drm/i915/i915_gem_gtt.h           |   3 +
>  drivers/gpu/drm/i915/i915_getparam.c          |   3 +
>  drivers/gpu/drm/i915/i915_sw_fence.c          |  28 +-
>  drivers/gpu/drm/i915/i915_sw_fence.h          |  23 +-
>  drivers/gpu/drm/i915/i915_vma.c               | 186 +++-
>  drivers/gpu/drm/i915/i915_vma.h               |  68 +-
>  drivers/gpu/drm/i915/i915_vma_types.h         |  39 +
>  include/uapi/drm/i915_drm.h                   | 264 +++++-
>  30 files changed, 3008 insertions(+), 546 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c
>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.h
>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>