Re: [PATCH v4 14/20] drm/xe/svm: Support DRM_XE_SVM_ATTR_PAT memory attribute

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

On Fri, Jun 13, 2025 at 06:25:52PM +0530, Himal Prasad Ghimiray wrote:
> This attributes sets the pat_index for the svm used vma range, which is
> utilized to ascertain the coherence.
> 
> v2 (Matthew Brost)
> - Pat index sanity check
> 
> Cc: Matthew Brost <matthew.brost@intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>

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

> ---
>  drivers/gpu/drm/xe/xe_vm_madvise.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c
> index 64352fbebd25..973627edb23c 100644
> --- a/drivers/gpu/drm/xe/xe_vm_madvise.c
> +++ b/drivers/gpu/drm/xe/xe_vm_madvise.c
> @@ -11,6 +11,7 @@
>  
>  #include "xe_bo.h"
>  #include "xe_gt_tlb_invalidation.h"
> +#include "xe_pat.h"
>  #include "xe_pt.h"
>  #include "xe_svm.h"
>  
> @@ -115,7 +116,13 @@ static void madvise_pat_index(struct xe_device *xe, struct xe_vm *vm,
>  			      struct xe_vma **vmas, int num_vmas,
>  			      struct drm_xe_madvise *op)
>  {
> -	/* Implementation pending */
> +	int i;
> +
> +	xe_assert(vm->xe, op->type == DRM_XE_VMA_ATTR_PAT);
> +
> +	for (i = 0; i < num_vmas; i++)
> +		vmas[i]->attr.pat_index = op->pat_index.val;
> +
>  }
>  
>  typedef void (*madvise_func)(struct xe_device *xe, struct xe_vm *vm,
> @@ -195,7 +202,13 @@ static int drm_xe_madvise_args_are_sane(struct xe_device *xe, const struct drm_x
>  			return -EINVAL;
>  		break;
>  	case DRM_XE_VMA_ATTR_PAT:
> -		/*TODO: Add valid pat check */
> +		u16 coh_mode = xe_pat_index_get_coh_mode(xe, args->pat_index.val);
> +
> +		if (XE_IOCTL_DBG(xe, !coh_mode))
> +			return -EINVAL;
> +
> +		if (XE_WARN_ON(coh_mode > XE_COH_AT_LEAST_1WAY))
> +			return -EINVAL;
>  		break;
>  	case DRM_XE_VMA_ATTR_PREFERRED_LOC:
>  		s32 fd = (s32)args->preferred_mem_loc.devmem_fd;
> -- 
> 2.34.1
>