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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 38F98C433E0 for ; Wed, 24 Feb 2021 08:38:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F69B64EF1 for ; Wed, 24 Feb 2021 08:38:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234552AbhBXIhp (ORCPT ); Wed, 24 Feb 2021 03:37:45 -0500 Received: from mx13.kaspersky-labs.com ([91.103.66.164]:45672 "EHLO mx13.kaspersky-labs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234502AbhBXIhM (ORCPT ); Wed, 24 Feb 2021 03:37:12 -0500 Received: from relay13.kaspersky-labs.com (unknown [127.0.0.10]) by relay13.kaspersky-labs.com (Postfix) with ESMTP id BC4F1521320; Wed, 24 Feb 2021 11:36:15 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kaspersky.com; s=mail202102; t=1614155775; bh=92YEeYk2M/SQMzHOI89FZGf8Gn2PDRHqkk0JTMPF8KI=; h=Subject:To:From:Message-ID:Date:MIME-Version:Content-Type; b=7UMKmygtSLxZCLITtXS96tgVzQzpnrmn6lTTgee6LBpaNybh5TiiH1VF8C852BgQq G4lS/i/yumO/8VvDeRtHF+etlJEvE1Yn0sofKfoI63W4khZhOVCHAi1yyM2DYfAi6M bnqXeSLZR9S863FOoOV0edjw3fOwlDLfqKDswwS6dgSTksQLXD9q8i7bLIXo0hxjZk TCDA/WcmaJjsqjXneVu7zL8LBdh81kMq9Ox1oHfwFqtZeztlrD2YU9c6zzwgA9nuxQ yVLGXuYOnqixK+d171eYNrJtHVfjRSKi8xormoXS32Cmi/tL0C2XujZJXJ57zo/JzU lMV46jARGJjsQ== Received: from mail-hq2.kaspersky.com (unknown [91.103.66.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (Client CN "mail-hq2.kaspersky.com", Issuer "Kaspersky MailRelays CA G3" (verified OK)) by mailhub13.kaspersky-labs.com (Postfix) with ESMTPS id 5B20C521319; Wed, 24 Feb 2021 11:36:15 +0300 (MSK) Received: from [10.16.171.77] (10.64.64.121) by hqmailmbx3.avp.ru (10.64.67.243) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2044.4; Wed, 24 Feb 2021 11:36:14 +0300 Subject: Re: [RFC PATCH v5 00/19] virtio/vsock: introduce SOCK_SEQPACKET support To: Stefano Garzarella CC: Stefan Hajnoczi , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , Jorgen Hansen , Andra Paraschiv , Norbert Slusarek , Colin Ian King , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "stsp2@yandex.ru" , "oxffffaa@gmail.com" References: <20210218053347.1066159-1-arseny.krasnov@kaspersky.com> <20210222142311.gekdd7gsm33wglos@steredhat> <20210223145016.ddavx6fihq4akdim@steredhat> <7a280168-cb54-ae26-4697-c797f6b04708@kaspersky.com> <20210224082319.yrmqr6zs7emvghw3@steredhat> <710d9dc2-3a0c-ea0b-fb02-68b460e6282e@kaspersky.com> <20210224083516.kkxlkoin632iaqik@steredhat> From: Arseny Krasnov Message-ID: Date: Wed, 24 Feb 2021 11:36:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210224083516.kkxlkoin632iaqik@steredhat> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.64.64.121] X-ClientProxiedBy: hqmailmbx2.avp.ru (10.64.67.242) To hqmailmbx3.avp.ru (10.64.67.243) X-KSE-ServerInfo: hqmailmbx3.avp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 5.9.16, Database issued on: 02/06/2021 23:52:08 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 0 X-KSE-AntiSpam-Info: Lua profiles 161679 [Feb 06 2021] X-KSE-AntiSpam-Info: LuaCore: 422 422 763e61bea9fcfcd94e075081cb96e065bc0509b4 X-KSE-AntiSpam-Info: Version: 5.9.16.0 X-KSE-AntiSpam-Info: Envelope from: arseny.krasnov@kaspersky.com X-KSE-AntiSpam-Info: {Tracking_content_type, plain} X-KSE-AntiSpam-Info: {Tracking_date, moscow} X-KSE-AntiSpam-Info: {Tracking_c_tr_enc, eight_bit} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: Rate: 0 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Deterministic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 02/06/2021 23:55:00 X-KSE-AttachmentFiltering-Interceptor-Info: no applicable attachment filtering rules found X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 06.02.2021 21:17:00 X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit X-KSE-AttachmentFiltering-Interceptor-Info: no applicable attachment filtering rules found X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit X-KLMS-Rule-ID: 52 X-KLMS-Message-Action: clean X-KLMS-AntiSpam-Status: not scanned, disabled by settings X-KLMS-AntiSpam-Interceptor-Info: not scanned X-KLMS-AntiPhishing: Clean, bases: 2021/02/24 06:25:00 X-KLMS-AntiVirus: Kaspersky Security for Linux Mail Server, version 8.0.3.30, bases: 2021/02/24 06:02:00 #16329712 X-KLMS-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 24.02.2021 11:35, Stefano Garzarella wrote: > On Wed, Feb 24, 2021 at 11:28:50AM +0300, Arseny Krasnov wrote: >> On 24.02.2021 11:23, Stefano Garzarella wrote: >>> On Wed, Feb 24, 2021 at 07:29:25AM +0300, Arseny Krasnov wrote: >>>> On 23.02.2021 17:50, Stefano Garzarella wrote: >>>>> On Mon, Feb 22, 2021 at 03:23:11PM +0100, Stefano Garzarella wrote: >>>>>> Hi Arseny, >>>>>> >>>>>> On Thu, Feb 18, 2021 at 08:33:44AM +0300, Arseny Krasnov wrote: >>>>>>> This patchset impelements support of SOCK_SEQPACKET for virtio >>>>>>> transport. >>>>>>> As SOCK_SEQPACKET guarantees to save record boundaries, so to >>>>>>> do it, two new packet operations were added: first for start of record >>>>>>> and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also, >>>>>>> both operations carries metadata - to maintain boundaries and payload >>>>>>> integrity. Metadata is introduced by adding special header with two >>>>>>> fields - message count and message length: >>>>>>> >>>>>>> struct virtio_vsock_seq_hdr { >>>>>>> __le32 msg_cnt; >>>>>>> __le32 msg_len; >>>>>>> } __attribute__((packed)); >>>>>>> >>>>>>> This header is transmitted as payload of SEQ_BEGIN and SEQ_END >>>>>>> packets(buffer of second virtio descriptor in chain) in the same way as >>>>>>> data transmitted in RW packets. Payload was chosen as buffer for this >>>>>>> header to avoid touching first virtio buffer which carries header of >>>>>>> packet, because someone could check that size of this buffer is equal >>>>>>> to size of packet header. To send record, packet with start marker is >>>>>>> sent first(it's header contains length of record and counter), then >>>>>>> counter is incremented and all data is sent as usual 'RW' packets and >>>>>>> finally SEQ_END is sent(it also carries counter of message, which is >>>>>>> counter of SEQ_BEGIN + 1), also after sedning SEQ_END counter is >>>>>>> incremented again. On receiver's side, length of record is known from >>>>>>> packet with start record marker. To check that no packets were dropped >>>>>>> by transport, counters of two sequential SEQ_BEGIN and SEQ_END are >>>>>>> checked(counter of SEQ_END must be bigger that counter of SEQ_BEGIN by >>>>>>> 1) and length of data between two markers is compared to length in >>>>>>> SEQ_BEGIN header. >>>>>>> Now as packets of one socket are not reordered neither on >>>>>>> vsock nor on vhost transport layers, such markers allows to restore >>>>>>> original record on receiver's side. If user's buffer is smaller that >>>>>>> record length, when all out of size data is dropped. >>>>>>> Maximum length of datagram is not limited as in stream socket, >>>>>>> because same credit logic is used. Difference with stream socket is >>>>>>> that user is not woken up until whole record is received or error >>>>>>> occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags. >>>>>>> Tests also implemented. >>>>>> I reviewed the first part (af_vsock.c changes), tomorrow I'll review >>>>>> the rest. That part looks great to me, only found a few minor issues. >>>>> I revieiwed the rest of it as well, left a few minor comments, but I >>>>> think we're well on track. >>>>> >>>>> I'll take a better look at the specification patch tomorrow. >>>> Great, Thank You >>>>> Thanks, >>>>> Stefano >>>>> >>>>>> In the meantime, however, I'm getting a doubt, especially with regard >>>>>> to other transports besides virtio. >>>>>> >>>>>> Should we hide the begin/end marker sending in the transport? >>>>>> >>>>>> I mean, should the transport just provide a seqpacket_enqueue() >>>>>> callbacl? >>>>>> Inside it then the transport will send the markers. This is because >>>>>> some transports might not need to send markers. >>>>>> >>>>>> But thinking about it more, they could actually implement stubs for >>>>>> that calls, if they don't need to send markers. >>>>>> >>>>>> So I think for now it's fine since it allows us to reuse a lot of >>>>>> code, unless someone has some objection. >>>> I thought about that, I'll try to implement it in next version. Let's see... >>> If you want to discuss it first, write down the idea you want to >>> implement, I wouldn't want to make you do unnecessary work. :-) >> Idea is simple, in iov iterator of 'struct msghdr' which is passed to >> >> enqueue callback we have two fields: 'iov_offset' which is byte >> >> offset inside io vector where next data must be picked and 'count' >> >> which is rest of unprocessed bytes in io vector. So in seqpacket >> >> enqueue callback if 'iov_offset' is 0 i'll send SEQBEGIN, and if >> >> 'count' is 0 i'll send SEQEND. >> > Got it, make sense and it's defently more transparent for the vsock > core! > Go head, maybe adding a comment in the vsock core explaining this, so > other developers can understand better if they want to support SEPACKET > in other transports. Ack > > Thanks, > Stefano > >