diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
index 28b8387f97b7..f7d70db16d76 100644
--- a/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
+++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
@@ -167,25 +167,4 @@ static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
  * - **flags**, holds various bits to control message handling
  */
 
-/*
- * Definition of the command transport message header (DW0)
- *
- * bit[4..0]	message len (in dwords)
- * bit[7..5]	reserved
- * bit[8]	response (G2H only)
- * bit[8]	write fence to desc (H2G only)
- * bit[9]	write status to H2G buff (H2G only)
- * bit[10]	send status back via G2H (H2G only)
- * bit[15..11]	reserved
- * bit[31..16]	action code
- */
-#define GUC_CT_MSG_LEN_SHIFT			0
-#define GUC_CT_MSG_LEN_MASK			0x1F
-#define GUC_CT_MSG_IS_RESPONSE			(1 << 8)
-#define GUC_CT_MSG_WRITE_FENCE_TO_DESC		(1 << 8)
-#define GUC_CT_MSG_WRITE_STATUS_TO_BUFF		(1 << 9)
-#define GUC_CT_MSG_SEND_STATUS			(1 << 10)
-#define GUC_CT_MSG_ACTION_SHIFT			16
-#define GUC_CT_MSG_ACTION_MASK			0xFFFF
-
 #endif /* _ABI_GUC_COMMUNICATION_CTB_ABI_H */
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index 4aa903be1317..f28a3a83742d 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -698,7 +698,7 @@ static int ct_send(struct intel_guc_ct *ct,
 
 	GEM_BUG_ON(!ct->enabled);
 	GEM_BUG_ON(!len);
-	GEM_BUG_ON(len & ~GUC_CT_MSG_LEN_MASK);
+	GEM_BUG_ON(len > GUC_CTB_HXG_MSG_MAX_LEN - GUC_CTB_HDR_LEN);
 	GEM_BUG_ON(!response_buf && response_buf_size);
 	might_sleep();