mlx5: Fail in create_cq if uar_page_index size is unsupported

The mlx5_ib_create_cq struct only has a 16 bit field for the uar page
index. Therefore, if the caller attempts to create a CQ with a uar page
index greater than or equal to 2^16, the function will fail explicitly
to avoid overflowing the struct field.

Fixes: 0c7212c ("mlx5: Support dyn UAR for CQ")
Signed-off-by: Akiva Goldberger <agoldberger@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>

providers/mlx5/verbs.c

@@ -1123,6 +1123,12 @@ static struct ibv_cq_ex *create_cq(struct ibv_context *context,
 		cmd_drv->flags |= MLX5_IB_CREATE_CQ_FLAGS_REAL_TIME_TS;
 
 	if (mctx->nc_uar) {
+		if (mctx->nc_uar->page_id >= (1ul << 16)) {
+			mlx5_dbg(fp, MLX5_DBG_CQ,
+				 "UAR page index larger than 16 bits is not supported\n");
+			errno = EINVAL;
+			goto err_db;
+		}
 		cmd_drv->flags |= MLX5_IB_CREATE_CQ_FLAGS_UAR_PAGE_INDEX;
 		cmd_drv->uar_page_index = mctx->nc_uar->page_id;
 	}