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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 189CDC43215 for ; Mon, 2 Dec 2019 02:56:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E301B20881 for ; Mon, 2 Dec 2019 02:56:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BxDvaYHT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727414AbfLBC4R (ORCPT ); Sun, 1 Dec 2019 21:56:17 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:37573 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727313AbfLBC4Q (ORCPT ); Sun, 1 Dec 2019 21:56:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575255375; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Nzz1d6fNBXps/DnIs5UAQiNGoXHliCVcfy6g5+mgQoM=; b=BxDvaYHT6UmdzK750JSUQrLk4a2p2ydsJgIGcwedUTq2jx2AeOMsqCdp1oDKTn9JBD8e+F LbbxasvdUHRsHWE1ZZOrUE7sTiAu50q2mBdmkwZ/8lxiMuIkJzF8Egrt9j4Ezrq9fQ5yUl aZLr+jC/wahg0HOIKkgJsA4pV0vOIMM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-142-zMKLkK5MNLCjozNN_3opZg-1; Sun, 01 Dec 2019 21:56:11 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B525B800D41; Mon, 2 Dec 2019 02:56:09 +0000 (UTC) Received: from [10.72.12.226] (ovpn-12-226.pek2.redhat.com [10.72.12.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7F8AF5D6A0; Mon, 2 Dec 2019 02:56:01 +0000 (UTC) Subject: Re: [RFC net-next 08/18] tun: run offloaded XDP program in Tx path To: David Miller , mst@redhat.com Cc: dsahern@gmail.com, prashantbhole.linux@gmail.com, ast@kernel.org, daniel@iogearbox.net, jakub.kicinski@netronome.com, hawk@kernel.org, john.fastabend@gmail.com, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, netdev@vger.kernel.org, qemu-devel@nongnu.org, kvm@vger.kernel.org References: <20191201.125621.1568040486743628333.davem@davemloft.net> <20191201163730-mutt-send-email-mst@kernel.org> <20191201.135439.2128495024712395126.davem@davemloft.net> From: Jason Wang Message-ID: <71cb13b9-fe81-c338-68dc-4d432360a0fb@redhat.com> Date: Mon, 2 Dec 2019 10:56:00 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191201.135439.2128495024712395126.davem@davemloft.net> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: zMKLkK5MNLCjozNN_3opZg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2019/12/2 =E4=B8=8A=E5=8D=885:54, David Miller wrote: > From: "Michael S. Tsirkin" > Date: Sun, 1 Dec 2019 16:40:22 -0500 > >> Right. But it is helpful to expose the supported functionality >> to guest in some way, if nothing else then so that >> guests can be moved between different hosts. >> >> Also, we need a way to report this kind of event to guest >> so it's possible to figure out what went wrong. > On the contrary, this is why it is of utmost importance that all > XDP implementations support the full suite of XDP facilities from > the very beginning. > > This is why we keep giving people a hard time when they add support > only for some of the XDP return values and semantics. Users will get > killed by this, and it makes XDP a poor technology to use because > behavior is not consistent across device types. > > That's not acceptable and I'll push back on anything that continues > this trend. > > If you can't HW offload it, kick it to software. We can try to work out a solution for XDP_REDIRECT. Thanks