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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 D8B61C433E0 for ; Mon, 18 May 2020 10:45:51 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 B710A207ED for ; Mon, 18 May 2020 10:45:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B710A207ED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jadH2-0001T7-GH; Mon, 18 May 2020 10:45:32 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jadH1-0001Sr-2J for xen-devel@lists.xenproject.org; Mon, 18 May 2020 10:45:31 +0000 X-Inumbo-ID: b0b61e06-98f4-11ea-a84b-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id b0b61e06-98f4-11ea-a84b-12813bfff9fa; Mon, 18 May 2020 10:45:29 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 7F9C6ABD1; Mon, 18 May 2020 10:45:31 +0000 (UTC) Subject: Re: [PATCH] public/io/netif.h: add a new extra type for XDP To: Denis Kirjanov References: <1589790285-1250-1-git-send-email-kda@linux-powerpc.org> <2615d770-c17b-26e0-4686-852ca122eeb4@suse.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Mon, 18 May 2020 12:45:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: xen-devel@lists.xenproject.org, paul@xen.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 18.05.20 12:37, Denis Kirjanov wrote: > On 5/18/20, Jürgen Groß wrote: >> On 18.05.20 11:52, Denis Kirjanov wrote: >>> On 5/18/20, Jürgen Groß wrote: >>>> On 18.05.20 10:24, Denis Kirjanov wrote: >>>>> The patch adds a new extra type to be able to diffirentiate >>>>> between RX responses on xen-netfront side with the adjusted offset >>>>> required for XDP processing. >>>>> >>>>> For Linux the offset value is going to be passed via xenstore. >>>> >>>> Why? I can only see disadvantages by using a different communication >>>> mechanism. >>> I see it like other features passed through xenstore and it requires >>> less changes to >>> other structures with the same final result. >> >> This is okay as long there is no Xenstore interaction required when the >> interface has been setup completely (i.e. only defining the needed >> offset for XDP is fine, enabling/disabling XDP at runtime should not be >> done via Xenstore IMO). > I've checked netfront-<--->netback interaction and found no problems with it. > Paul found an issue that the value of the netfront state hasn't been > re-read (during unbind-bind sequence in dom0) and I've fixed it the > patch for the guest I don't say your variant isn't working, but a feature being switchable dynamically AND needing a ring page synchronization anyway should IMO be switched via a specific ring page request. I might have not the complete picture, so in case you have a good reason to do it via Xenstore, fine, but "I'm seeing no problem with it" is no good reason for a specific design decision. > >> >> And please, no guest type special casing. Please replace "Linux" by e.g. >> "The guest" (with additional tweaking of the following sentence). > > Oh, just sent v2. I'll fix a comment. Thanks. Juergen