Re: [Intel-xe] [PATCH] drm/xe: remove header variable from parse_g2h_msg

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Jul 28, 2023 at 09:02:11PM -0700, Matthew Brost wrote:
> The header variable is unused, remove it.
> 
> Suggested-by: Oded Gabbay <ogabbay@kernel.org>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_guc_ct.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
> index d322eadbe75a..6c757efa88b8 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> @@ -829,12 +829,11 @@ static int parse_g2h_response(struct xe_guc_ct *ct, u32 *msg, u32 len)
>  static int parse_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
>  {
>  	struct xe_device *xe = ct_to_xe(ct);
> -	u32 header, hxg, origin, type;
> +	u32 hxg, origin, type;
>  	int ret;
>  
>  	lockdep_assert_held(&ct->lock);
>  
> -	header = msg[0];

Shouldn't we be parsing the header and checking for the len?
against corrupted messages?

something like on i915's intel_guc_ct.c:

  /* message len with header */
        len = FIELD_GET(GUC_CTB_MSG_0_NUM_DWORDS, header) + GUC_CTB_MSG_MIN_LEN;
 	if (unlikely(len > (u32)available)) {
                CT_ERROR(ct, "Incomplete message %*ph %*ph %*ph\n",
	                 4, &header,
                         4 * (head + available - 1 > size ?
                              size - head : available - 1), &cmds[head],
	                 4 * (head + available - 1 > size ?
                              available - 1 - size + head : 0), &cmds[0]);
                desc->status |= GUC_CTB_STATUS_UNDERFLOW;
	        goto corrupted;
        }


>  	hxg = msg[1];
>  
>  	origin = FIELD_GET(GUC_HXG_MSG_0_ORIGIN, hxg);
> -- 
> 2.34.1
>