GUC_CTB_HXG_MSG_MAX_LEN
GEM_BUG_ON(len > GUC_CTB_HXG_MSG_MAX_LEN - GUC_CTB_HDR_LEN);
!g2h_has_room(ct, GUC_CTB_HXG_MSG_MAX_LEN))) {
g2h_reserve_space(ct, GUC_CTB_HXG_MSG_MAX_LEN);
g2h_release_space(ct, GUC_CTB_HXG_MSG_MAX_LEN);