From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 88026A0548; Thu, 2 Jun 2022 11:07:16 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 414EA40691; Thu, 2 Jun 2022 11:07:16 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mails.dpdk.org (Postfix) with ESMTP id 3D60D4021E for ; Thu, 2 Jun 2022 11:07:15 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654160834; 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=7Q+9ruDq+PRD6otETZkinWWGjlGsvAmLPQp4uGZFCFk=; b=aKaTBQoNKHlDjb3ML0ZQdraIB3fEe/qKeEXk6Yx0cVTefFq8NPGHb0vMF1rnm98KbdCnFH ds+SrwWdLeLlqm0cGWIAKiQXPdiLIEtgKXQDONWcNZjyaARdXrCuvIM+uiH4t4gvYGN58a Ll8OVJPUnqlZ9dO3KB+g5Dc8lMihUdk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-214-928YFjc1NSqbDh1eOmkg8Q-1; Thu, 02 Jun 2022 05:07:11 -0400 X-MC-Unique: 928YFjc1NSqbDh1eOmkg8Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 63838185A794; Thu, 2 Jun 2022 09:07:11 +0000 (UTC) Received: from [10.39.208.18] (unknown [10.39.208.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1D5261121314; Thu, 2 Jun 2022 09:07:09 +0000 (UTC) Message-ID: <4948f8e2-5fc9-2821-4120-3fdb4111ddd3@redhat.com> Date: Thu, 2 Jun 2022 11:07:08 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 6/6] net/vhost: perform SW checksum in Tx path To: "Ma, WenwuX" , "dev@dpdk.org" , "jasowang@redhat.com" , "Xia, Chenbo" , "david.marchand@redhat.com" , "olivier.matz@6wind.com" Cc: "stable@dpdk.org" References: <20220505102729.821075-1-maxime.coquelin@redhat.com> <20220505102729.821075-7-maxime.coquelin@redhat.com> From: Maxime Coquelin In-Reply-To: X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=maxime.coquelin@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Hi Wenwu, Sorry, I missed your review. On 5/7/22 05:20, Ma, WenwuX wrote: > >> -----Original Message----- >> From: Maxime Coquelin >> Sent: 2022年5月5日 18:27 >> To: dev@dpdk.org; jasowang@redhat.com; Xia, Chenbo >> ; david.marchand@redhat.com; >> olivier.matz@6wind.com >> Cc: stable@dpdk.org; Maxime Coquelin >> Subject: [PATCH 6/6] net/vhost: perform SW checksum in Tx path >> >> Virtio specification supports guest checksum offloading for L4, which is >> enabled with VIRTIO_NET_F_GUEST_CSUM feature negotiation. However, >> the Vhost PMD does not advertise Tx checksum offload capabilities. >> >> Advertising these offload capabilities at the ethdev level is not enough, >> because we could still end-up with the application enabling these offloads >> while the guest not negotiating it. >> >> This patch advertizes the Tx checksum offload capabilities, and introduces a >> compatibility layer to cover the case VIRTIO_NET_F_GUEST_CSUM has not >> been negotiated but the application does configure the Tx checksum >> offloads. This function performs the L4 Tx checksum in SW for UDP and TCP. >> Compared to Rx SW checksum, the Tx SW checksum function needs to >> compute the pseudo-header checksum, as we cannot knwo whether it was >> done before. >> >> This patch does not advertize SCTP checksum offloading capability for now, >> but it could be handled later if the need arises. > > In virtio_enqueue_offload(), if RTE_MBUF_F_TX_IP_CKSUM is set, we will > performs the L3 Tx checksum, why do not we advertise IPV4 checksum offloading capability? > Will we advertise it later? > Indeed, we have an IPv4 SW checksum fallback in Vhost library. We could think about adding the capability, but that's not urgent I think. Do you have a use-case where it is needed? Regards, Maxime