[Intel-gfx] [PATCH 01/12] drm/i915/gt: Stop cross-polluting PIN_GLOBAL with PIN_USER with no-ppgtt

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> In order to keep userptr distinct from ggtt mmaps in the eyes of
> lockdep, we need to avoid marking those userptr vma as PIN_GLOBAL. (So
> long as we comply with only using them as local PIN_USER!)
>
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/1880
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Acked-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/gt/intel_ggtt.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> index 66165b10256e..8c275f8588c3 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> @@ -424,22 +424,17 @@ static int ggtt_bind_vma(struct i915_vma *vma,
>  	struct drm_i915_gem_object *obj = vma->obj;
>  	u32 pte_flags;
>  
> +	if (i915_vma_is_bound(vma, ~flags & I915_VMA_BIND_MASK))
> +		return 0;
> +
>  	/* Applicable to VLV (gen8+ do not support RO in the GGTT) */
>  	pte_flags = 0;
>  	if (i915_gem_object_is_readonly(obj))
>  		pte_flags |= PTE_READ_ONLY;
>  
>  	vma->vm->insert_entries(vma->vm, vma, cache_level, pte_flags);
> -
>  	vma->page_sizes.gtt = I915_GTT_PAGE_SIZE;
>  
> -	/*
> -	 * Without aliasing PPGTT there's no difference between
> -	 * GLOBAL/LOCAL_BIND, it's all the same ptes. Hence unconditionally
> -	 * upgrade to both bound if we bind either to avoid double-binding.
> -	 */
> -	atomic_or(I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND, &vma->flags);
> -
>  	return 0;
>  }
>  
> -- 
> 2.20.1
>
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