[Intel-gfx] [PATCH 12/15] drm/i915/guc: Prepare to process incoming requests from CT

[Chris Wilson]

Quoting Michal Wajdeczko (2017-08-04 17:27:09)
>  static inline const char *guc_ct_buffer_type_to_str(u32 type)
> @@ -600,13 +609,76 @@ static int guc_handle_response(struct intel_guc *guc, const u32 *data)
>  static int guc_handle_request(struct intel_guc *guc, const u32 *data)
>  {
>         u32 header = data[0];
> +       u32 len = ct_header_get_len(header) + 1; /* total len with header */
> +       struct ct_incoming_request *request;
> +       unsigned long flags;
>  
>         GEM_BUG_ON(ct_header_is_response(header));
>         /* data layout beyond header is request specific */
>  
> +       request = kmalloc(sizeof(*request), GFP_ATOMIC);
> +       if (unlikely(!request)) {
> +               DRM_ERROR("CT: dropping request %*phn\n", 4*len, data);
> +               return 0; /* XXX: -ENOMEM ? */
> +       }
> +
> +       GEM_BUG_ON(len > GUC_CT_MSG_LEN_MASK + 1);

This is incoming from the guc, if we can validate it, do so. Keep
GEM_BUG_ON() for programming errors and absolute catastrophe.
-Chris