[PATCH] drm/xe/bo: Don't include the CCS metadata in the dma-buf sg-table

[PATCH] drm/xe/bo: Don't include the CCS metadata in the dma-buf sg-table

[Thomas Hellström]

Some Xe bos are allocated with extra backing-store for the CCS
metadata. It's never been the intention to share the CCS metadata
when exporting such bos as dma-buf. Don't include it in the
dma-buf sg-table.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: <stable@vger.kernel.org> # v6.8+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/xe/xe_dma_buf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
index 54e42960daad..7c74a31d4486 100644
--- a/drivers/gpu/drm/xe/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/xe_dma_buf.c
@@ -124,7 +124,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
 	case XE_PL_TT:
 		sgt = drm_prime_pages_to_sg(obj->dev,
 					    bo->ttm.ttm->pages,
-					    bo->ttm.ttm->num_pages);
+					    obj->size >> PAGE_SHIFT);
 		if (IS_ERR(sgt))
 			return sgt;
 
-- 
2.51.1

Re: [PATCH] drm/xe/bo: Don't include the CCS metadata in the dma-buf sg-table

[Matthew Brost]

On Tue, Dec 09, 2025 at 09:49:20PM +0100, Thomas Hellström wrote:
> Some Xe bos are allocated with extra backing-store for the CCS
> metadata. It's never been the intention to share the CCS metadata
> when exporting such bos as dma-buf. Don't include it in the
> dma-buf sg-table.
> 

Indeed, good catch.

> Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v6.8+
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>  drivers/gpu/drm/xe/xe_dma_buf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
> index 54e42960daad..7c74a31d4486 100644
> --- a/drivers/gpu/drm/xe/xe_dma_buf.c
> +++ b/drivers/gpu/drm/xe/xe_dma_buf.c
> @@ -124,7 +124,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
>  	case XE_PL_TT:
>  		sgt = drm_prime_pages_to_sg(obj->dev,
>  					    bo->ttm.ttm->pages,
> -					    bo->ttm.ttm->num_pages);
> +					    obj->size >> PAGE_SHIFT);
>  		if (IS_ERR(sgt))
>  			return sgt;
>  
> -- 
> 2.51.1
> 

Re: drm/xe/bo: Don't include the CCS metadata in the dma-buf sg-table

[Karol Wachowski]

On 12/9/2025 9:49 PM, Thomas Hellström wrote:
> Some Xe bos are allocated with extra backing-store for the CCS
> metadata. It's never been the intention to share the CCS metadata
> when exporting such bos as dma-buf. Don't include it in the
> dma-buf sg-table.
> 
> Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v6.8+
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Reviewed-by: Matthew Brost <matthew.brost@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_dma_buf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
> index 54e42960daad..7c74a31d4486 100644
> --- a/drivers/gpu/drm/xe/xe_dma_buf.c
> +++ b/drivers/gpu/drm/xe/xe_dma_buf.c
> @@ -124,7 +124,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
>  	case XE_PL_TT:
>  		sgt = drm_prime_pages_to_sg(obj->dev,
>  					    bo->ttm.ttm->pages,
> -					    bo->ttm.ttm->num_pages);
> +					    obj->size >> PAGE_SHIFT);
>  		if (IS_ERR(sgt))
>  			return sgt;
>  
Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>