Re: [PATCH 1/2] drm/xe/guc: Unblock GuC buffer cache for all modes

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

On Tue, May 13, 2025 at 12:00:17AM +0200, Michal Wajdeczko wrote:
> Today we were using GuC buffer cache only in the PF mode, but
> shortly we will want to use it also in native and VF mode.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Should we mark these patches as fixes? A malicious user could consume
all the VRAM on the device by changing wedged mode via debugfs enough
times... 

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

> ---
>  drivers/gpu/drm/xe/xe_guc.c     | 4 ++++
>  drivers/gpu/drm/xe/xe_guc_buf.c | 4 ----
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index bac5471a1a78..350434a8b953 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -710,6 +710,10 @@ static int vf_guc_init_post_hwconfig(struct xe_guc *guc)
>  	if (err)
>  		return err;
>  
> +	err = xe_guc_buf_cache_init(&guc->buf);
> +	if (err)
> +		return err;
> +
>  	/* XXX xe_guc_db_mgr_init not needed for now */
>  
>  	return 0;
> diff --git a/drivers/gpu/drm/xe/xe_guc_buf.c b/drivers/gpu/drm/xe/xe_guc_buf.c
> index 0193c94dd6a0..14a07dca48e7 100644
> --- a/drivers/gpu/drm/xe/xe_guc_buf.c
> +++ b/drivers/gpu/drm/xe/xe_guc_buf.c
> @@ -37,10 +37,6 @@ int xe_guc_buf_cache_init(struct xe_guc_buf_cache *cache)
>  	struct xe_gt *gt = cache_to_gt(cache);
>  	struct xe_sa_manager *sam;
>  
> -	/* XXX: currently it's useful only for the PF actions */
> -	if (!IS_SRIOV_PF(gt_to_xe(gt)))
> -		return 0;
> -
>  	sam = __xe_sa_bo_manager_init(gt_to_tile(gt), SZ_8K, 0, sizeof(u32));
>  	if (IS_ERR(sam))
>  		return PTR_ERR(sam);
> -- 
> 2.47.1
>