Re: [PATCH 1/2] drm/xe/bo: Add xe_bo_addr_iter.

[Matthew Brost <matthew.brost@intel.com>]

On Fri, Jun 12, 2026 at 04:11:20PM +0200, Maarten Lankhorst wrote:
> For display we iterate often over the pinned VRAM/system memory BO.
> Add some code to speed up DPT/GGTT programming.
> 
> Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
> ---
>  drivers/gpu/drm/xe/xe_bo.c | 45 ++++++++++++++++++++++----------------
>  drivers/gpu/drm/xe/xe_bo.h |  3 +++
>  2 files changed, 29 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index 5275badb024cd..38223bb8b74c6 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -3143,6 +3143,30 @@ bool xe_bo_is_xe_bo(struct ttm_buffer_object *bo)
>  	return false;
>  }
>  
> +void xe_bo_addr_iter_first(struct xe_bo *bo, struct xe_res_cursor *cur, u64 offset, u64 size)

Kernel doc.

> +{
> +	struct xe_device *xe = xe_bo_device(bo);
> +
> +	if (!xe_bo_is_vram(bo) && !xe_bo_is_stolen(bo)) {
> +		xe_assert(xe, bo->ttm.ttm);
> +
> +		xe_res_first_sg(xe_bo_sg(bo), offset, size, cur);
> +	} else {
> +		xe_res_first(bo->ttm.resource, offset, size, cur);
> +
> +		xe_assert(xe, !cur->dma_addr);
> +		cur->dma_start = vram_region_gpu_offset(bo->ttm.resource);
> +	}
> +}
> +
> +dma_addr_t xe_bo_addr_iter_addr(struct xe_res_cursor *cur)

Kernel doc.

> +{
> +	if (cur->mem_type == XE_PL_TT)
> +		return xe_res_dma(cur);
> +
> +	return cur->start + cur->dma_start;
> +}
> +
>  /*
>   * Resolve a BO address. There is no assert to check if the proper lock is held
>   * so it should only be used in cases where it is not fatal to get the wrong
> @@ -3151,27 +3175,10 @@ bool xe_bo_is_xe_bo(struct ttm_buffer_object *bo)
>   */
>  dma_addr_t __xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size)
>  {
> -	struct xe_device *xe = xe_bo_device(bo);
>  	struct xe_res_cursor cur;
> -	u64 page;
> -
> -	xe_assert(xe, page_size <= PAGE_SIZE);
> -	page = offset >> PAGE_SHIFT;
> -	offset &= (PAGE_SIZE - 1);

I'd mention in the commit message the code which aligns the addeess to a
page in __xe_bo_addr has been droppped.

Otherwise LGTM.

Matt

>  
> -	if (!xe_bo_is_vram(bo) && !xe_bo_is_stolen(bo)) {
> -		xe_assert(xe, bo->ttm.ttm);
> -
> -		xe_res_first_sg(xe_bo_sg(bo), page << PAGE_SHIFT,
> -				page_size, &cur);
> -		return xe_res_dma(&cur) + offset;
> -	} else {
> -		struct xe_res_cursor cur;
> -
> -		xe_res_first(bo->ttm.resource, page << PAGE_SHIFT,
> -			     page_size, &cur);
> -		return cur.start + offset + vram_region_gpu_offset(bo->ttm.resource);
> -	}
> +	xe_bo_addr_iter_first(bo, &cur, offset, page_size);
> +	return xe_bo_addr_iter_addr(&cur);
>  }
>  
>  dma_addr_t xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size)
> diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> index 4128dbf7fe695..9155e424f081c 100644
> --- a/drivers/gpu/drm/xe/xe_bo.h
> +++ b/drivers/gpu/drm/xe/xe_bo.h
> @@ -111,6 +111,7 @@ enum xe_madv_purgeable_state {
>  };
>  
>  struct sg_table;
> +struct xe_res_cursor;
>  
>  struct xe_bo *xe_bo_alloc(void);
>  void xe_bo_free(struct xe_bo *bo);
> @@ -370,6 +371,8 @@ static inline void xe_bo_unpin_map_no_vm(struct xe_bo *bo)
>  }
>  
>  bool xe_bo_is_xe_bo(struct ttm_buffer_object *bo);
> +void xe_bo_addr_iter_first(struct xe_bo *bo, struct xe_res_cursor *cur, u64 offset, u64 size);
> +dma_addr_t xe_bo_addr_iter_addr(struct xe_res_cursor *cur);
>  dma_addr_t __xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size);
>  dma_addr_t xe_bo_addr(struct xe_bo *bo, u64 offset, size_t page_size);
>  
> -- 
> 2.53.0
>