From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38F42C432C0 for ; Sun, 1 Dec 2019 20:57:12 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0AB672082E for ; Sun, 1 Dec 2019 20:57:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0AB672082E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55454 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ibWHH-0005QB-18 for qemu-devel@archiver.kernel.org; Sun, 01 Dec 2019 15:57:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48616) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ibWGe-0004yC-Tk for qemu-devel@nongnu.org; Sun, 01 Dec 2019 15:56:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ibWGe-0005kM-1a for qemu-devel@nongnu.org; Sun, 01 Dec 2019 15:56:32 -0500 Received: from shards.monkeyblade.net ([2620:137:e000::1:9]:50328) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ibWGd-0005f1-Sq for qemu-devel@nongnu.org; Sun, 01 Dec 2019 15:56:32 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 59A8114F64DD2; Sun, 1 Dec 2019 12:56:24 -0800 (PST) Date: Sun, 01 Dec 2019 12:56:21 -0800 (PST) Message-Id: <20191201.125621.1568040486743628333.davem@davemloft.net> To: dsahern@gmail.com Subject: Re: [RFC net-next 08/18] tun: run offloaded XDP program in Tx path From: David Miller In-Reply-To: References: <20191126100744.5083-1-prashantbhole.linux@gmail.com> <20191126100744.5083-9-prashantbhole.linux@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 01 Dec 2019 12:56:25 -0800 (PST) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2620:137:e000::1:9 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: songliubraving@fb.com, jakub.kicinski@netronome.com, hawk@kernel.org, daniel@iogearbox.net, mst@redhat.com, netdev@vger.kernel.org, jasowang@redhat.com, john.fastabend@gmail.com, ast@kernel.org, qemu-devel@nongnu.org, prashantbhole.linux@gmail.com, kvm@vger.kernel.org, yhs@fb.com, andriin@fb.com, kafai@fb.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: David Ahern Date: Sun, 1 Dec 2019 09:39:54 -0700 > Below you just drop the packet which is going to be a bad user > experience. A better user experience is to detect XDP return codes a > program uses, catch those that are not supported for this use case and > fail the install of the program. This is not universally possible. Return codes can be calculated dynamically, come from maps potentially shared with other bpf programs, etc. So unfortunately this suggestion is not tenable.