[PATCH v2 2/7] drm/amdgpu: Implement mmap as GEM object function

[Christian König]

Am 15.04.21 um 12:17 schrieb Thomas Zimmermann:
> Moving the driver-specific mmap code into a GEM object function allows
> for using DRM helpers for various mmap callbacks.
>
> This change resolves several inconsistencies between regular mmap and
> prime-based mmap. The vm_ops field in vma is now set for all mmap'ed
> areas. Previously it way only set for regular mmap calls, prime-based
> mmap used TTM's default vm_ops. The function amdgpu_verify_access() is
> no longer being called and therefore removed by this patch.
>
> As a side effect, amdgpu_ttm_vm_ops and amdgpu_ttm_fault() are now
> implemented in amdgpu's GEM code.
>
> v2:
> 	* rename amdgpu_ttm_vm_ops and amdgpu_ttm_fault() to
> 	  amdgpu_gem_vm_ops and amdgpu_gem_fault() (Christian)
> 	* the check for kfd_bo has meanwhile been removed
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>

[SNIP]
> +static int amdgpu_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> +{

Mhm, just double checking this function is now a core GEM function and 
not prime specific?

If yes maybe drop the _prime part.

> +	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> +	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> +	unsigned long asize = amdgpu_bo_size(bo);
> +
> +	if (!vma->vm_file)
> +		return -ENODEV;
> +
> +	if (!adev)
> +		return -ENODEV;
> +
> +	/* Check for valid size. */
> +	if (asize < vma->vm_end - vma->vm_start)
> +		return -EINVAL;

Shouldn't we have that check in the common code?

Apart from that looks good to me.

Christian.

> +
> +	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
> +	    (bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)) {
> +		return -EPERM;
> +	}
> +
> +	return drm_gem_ttm_mmap(obj, vma);
> +}
> +
>   static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
>   	.free = amdgpu_gem_object_free,
>   	.open = amdgpu_gem_object_open,
> @@ -212,6 +266,8 @@ static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
>   	.export = amdgpu_gem_prime_export,
>   	.vmap = drm_gem_ttm_vmap,
>   	.vunmap = drm_gem_ttm_vunmap,
> +	.mmap = amdgpu_gem_prime_mmap,
> +	.vm_ops = &amdgpu_gem_vm_ops,
>   };
>   
>   /*
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 1485f33c3cc7..d4083c19402b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -152,25 +152,6 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
>   	*placement = abo->placement;
>   }
>   
> -/**
> - * amdgpu_verify_access - Verify access for a mmap call
> - *
> - * @bo:	The buffer object to map
> - * @filp: The file pointer from the process performing the mmap
> - *
> - * This is called by ttm_bo_mmap() to verify whether a process
> - * has the right to mmap a BO to their process space.
> - */
> -static int amdgpu_verify_access(struct ttm_buffer_object *bo, struct file *filp)
> -{
> -	struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
> -
> -	if (amdgpu_ttm_tt_get_usermm(bo->ttm))
> -		return -EPERM;
> -	return drm_vma_node_verify_access(&abo->tbo.base.vma_node,
> -					  filp->private_data);
> -}
> -
>   /**
>    * amdgpu_ttm_map_buffer - Map memory into the GART windows
>    * @bo: buffer object to map
> @@ -1522,7 +1503,6 @@ static struct ttm_device_funcs amdgpu_bo_driver = {
>   	.eviction_valuable = amdgpu_ttm_bo_eviction_valuable,
>   	.evict_flags = &amdgpu_evict_flags,
>   	.move = &amdgpu_bo_move,
> -	.verify_access = &amdgpu_verify_access,
>   	.delete_mem_notify = &amdgpu_bo_delete_mem_notify,
>   	.release_notify = &amdgpu_bo_release_notify,
>   	.io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
> @@ -1897,50 +1877,6 @@ void amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
>   	adev->mman.buffer_funcs_enabled = enable;
>   }
>   
> -static vm_fault_t amdgpu_ttm_fault(struct vm_fault *vmf)
> -{
> -	struct ttm_buffer_object *bo = vmf->vma->vm_private_data;
> -	vm_fault_t ret;
> -
> -	ret = ttm_bo_vm_reserve(bo, vmf);
> -	if (ret)
> -		return ret;
> -
> -	ret = amdgpu_bo_fault_reserve_notify(bo);
> -	if (ret)
> -		goto unlock;
> -
> -	ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
> -				       TTM_BO_VM_NUM_PREFAULT, 1);
> -	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
> -		return ret;
> -
> -unlock:
> -	dma_resv_unlock(bo->base.resv);
> -	return ret;
> -}
> -
> -static const struct vm_operations_struct amdgpu_ttm_vm_ops = {
> -	.fault = amdgpu_ttm_fault,
> -	.open = ttm_bo_vm_open,
> -	.close = ttm_bo_vm_close,
> -	.access = ttm_bo_vm_access
> -};
> -
> -int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma)
> -{
> -	struct drm_file *file_priv = filp->private_data;
> -	struct amdgpu_device *adev = drm_to_adev(file_priv->minor->dev);
> -	int r;
> -
> -	r = ttm_bo_mmap(filp, vma, &adev->mman.bdev);
> -	if (unlikely(r != 0))
> -		return r;
> -
> -	vma->vm_ops = &amdgpu_ttm_vm_ops;
> -	return 0;
> -}
> -
>   int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t src_offset,
>   		       uint64_t dst_offset, uint32_t byte_count,
>   		       struct dma_resv *resv,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> index dec0db8b0b13..6e51faad7371 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
> @@ -146,7 +146,6 @@ int amdgpu_fill_buffer(struct amdgpu_bo *bo,
>   			struct dma_resv *resv,
>   			struct dma_fence **fence);
>   
> -int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma);
>   int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo);
>   int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo);
>   uint64_t amdgpu_ttm_domain_start(struct amdgpu_device *adev, uint32_t type);