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 A805EC432C0 for ; Mon, 2 Dec 2019 02:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CBF920675 for ; Mon, 2 Dec 2019 02:45:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ewlo5Km8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727356AbfLBCp5 (ORCPT ); Sun, 1 Dec 2019 21:45:57 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:41461 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727298AbfLBCp5 (ORCPT ); Sun, 1 Dec 2019 21:45:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575254756; 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=A5SS3ilN57be+dKCEWLuoWs9cfIT9f/3tFpS4mzNsu0=; b=Ewlo5Km8l2KemrhI66Oqo5lcLxzuOMeSPUW4qx+886XRk9f9SJNMYbUN1hsOI0/ptM66PX vmiXATzbG9nvcsBwR3kvAgKQjUpsVNsCaKbZ9g9ox7nJlB2iu0I8I+6tju0HxYXV7zqoTH aVI9QXJsNAjf2bnW7IrjqLB145w/ofM= 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-393-M13GqMyeMo-aN-w95nrSwQ-1; Sun, 01 Dec 2019 21:45:52 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1950E107ACC4; Mon, 2 Dec 2019 02:45:49 +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 5CFB260BFB; Mon, 2 Dec 2019 02:45:41 +0000 (UTC) Subject: Re: [RFC net-next 08/18] tun: run offloaded XDP program in Tx path To: David Ahern , Prashant Bhole , "David S . Miller" , "Michael S . Tsirkin" Cc: Alexei Starovoitov , Daniel Borkmann , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , netdev@vger.kernel.org, qemu-devel@nongnu.org, kvm@vger.kernel.org References: <20191126100744.5083-1-prashantbhole.linux@gmail.com> <20191126100744.5083-9-prashantbhole.linux@gmail.com> From: Jason Wang Message-ID: Date: Mon, 2 Dec 2019 10:45:39 +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: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: M13GqMyeMo-aN-w95nrSwQ-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=8812:39, David Ahern wrote: > On 11/26/19 4:07 AM, Prashant Bhole wrote: >> run offloaded XDP program as soon as packet is removed from the ptr >> ring. Since this is XDP in Tx path, the traditional handling of >> XDP actions XDP_TX/REDIRECT isn't valid. For this reason we call >> do_xdp_generic_core instead of do_xdp_generic. do_xdp_generic_core >> just runs the program and leaves the action handling to us. > What happens if an offloaded program returns XDP_REDIRECT? > > 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. Yes, this could be done in the guest. Thanks