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 4FA55A0C43; Mon, 18 Oct 2021 09:54:14 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 13426410E1; Mon, 18 Oct 2021 09:54:14 +0200 (CEST) Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) by mails.dpdk.org (Postfix) with ESMTP id 5DD9140141 for ; Mon, 18 Oct 2021 09:54:12 +0200 (CEST) Received: by mail-wr1-f51.google.com with SMTP id u18so39780087wrg.5 for ; Mon, 18 Oct 2021 00:54:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind.com; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=4B17mFTKeGTi2FmuN6b3Izc/yqvsmZMJegb1+JK/M9I=; b=EN/J90muDR9wc0WV9byEda1oGgHp8DvNqJ4D1FxKkYNjV9qfKbJ6gADrdjghXnfQwa T8eZoX14ood9rWz+rWBWDLYbH+HY4ssGPmTQtj1G6gA6fRrOnQugH87i322jkLth41yR DGYMj3omW7arZxF9VX7JMCGwUptRwCdT9iFlfQjGrchOI6DHZ/BUn2nURVvdX01lzskh MHGQuU2bDi6NUZyJfOD7YDruGc8bLzyRojDK3BPq2DPgna3zWj9NVYnEAfcHUFKSoerC NuMuTxMFLSgGjVI9XDwhduAPLdzjeAu2mpLSX/mkS0FpvSHO5NCbZsN0B4Ou953EeItH EObw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=4B17mFTKeGTi2FmuN6b3Izc/yqvsmZMJegb1+JK/M9I=; b=Un7PxU/nBVvhFygBw5oSqUJsei43YvOqOuKi6wYyCCFm9FAXYEAikCw52RxOMMwQbC NLtlzsIxl/KYfdCyboxOFlp5eIxrKUFxpnGMy01w7OcEDNgZyPeoSteV+YmTrVQx/431 aaYEuM0EXO0sh73Wkh7/CcpH2EmhJmvv0og1u11jrkYofyvjQS9CtSfWRJdFIOTcANEK gifoqjGILv2RdRy3nZeBkx/fkVGlid6M1IZmdorpu3tO9SGSHVRh4fhd8FyG2v9tUz18 FUkd/eJL63nIafLwbnVgWgi4Eg4T6ih9HsfNS5RGghb4GzGHLtrWd94VDAGEyjccq73P Rc5w== X-Gm-Message-State: AOAM532j48uSIlGfz/Qwb8W2o0ClbfeoO2Ec8XUXWXLd2/UPWzjI+S5n XxrymTlBNN+rW6OfIZQUWlG8MA== X-Google-Smtp-Source: ABdhPJxXIa7/7iUzDxoHiw9iET0mjIZW9oOvHwPD+wLIuxgO5kdZfxQOXaJER5ius4OxuSeuy3RkaA== X-Received: by 2002:a5d:59a7:: with SMTP id p7mr33652386wrr.141.1634543651987; Mon, 18 Oct 2021 00:54:11 -0700 (PDT) Received: from 6wind.com ([2a01:e0a:5ac:6460:c065:401d:87eb:9b25]) by smtp.gmail.com with ESMTPSA id l124sm18060921wml.8.2021.10.18.00.54.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Oct 2021 00:54:10 -0700 (PDT) Date: Mon, 18 Oct 2021 09:54:10 +0200 From: Olivier Matz To: Andrew Rybchenko Cc: "Xia, Chenbo" , Ivan Malov , "dev@dpdk.org" , Maxime Coquelin , "stable@dpdk.org" , Yuanhan Liu Message-ID: References: <20210830142655.18373-1-ivan.malov@oktetlabs.ru> <20210916184955.2755-1-ivan.malov@oktetlabs.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [dpdk-dev] [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel packets 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 Sender: "dev" On Mon, Oct 18, 2021 at 10:04:46AM +0300, Andrew Rybchenko wrote: > On 10/15/21 11:32 AM, Olivier Matz wrote: > > On Thu, Oct 14, 2021 at 07:12:29AM +0000, Xia, Chenbo wrote: > >>> -----Original Message----- > >>> From: Ivan Malov > >>> Sent: Friday, September 17, 2021 2:50 AM > >>> To: dev@dpdk.org > >>> Cc: Maxime Coquelin ; stable@dpdk.org; Andrew > >>> Rybchenko ; Xia, Chenbo ; > >>> Yuanhan Liu ; Olivier Matz > >>> > >>> Subject: [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel > >>> packets > >>> > >>> Tx prepare method calls rte_net_intel_cksum_prepare(), which > >>> handles tunnel packets correctly, but Tx burst path does not > >>> take tunnel presence into account when computing the offsets. > >>> > >>> Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload") > >>> Cc: stable@dpdk.org > >>> > >>> Signed-off-by: Ivan Malov > >>> Reviewed-by: Andrew Rybchenko > >>> --- > >>> drivers/net/virtio/virtqueue.h | 9 ++++++--- > >>> 1 file changed, 6 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h > >>> index 03957b2bd0..b83ff32efb 100644 > >>> --- a/drivers/net/virtio/virtqueue.h > >>> +++ b/drivers/net/virtio/virtqueue.h > >>> @@ -620,19 +620,21 @@ static inline void > >>> virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie) > >>> { > >>> uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK; > >>> + uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ? > >>> + cookie->outer_l2_len + cookie->outer_l3_len : 0; > >>> > >>> if (cookie->ol_flags & PKT_TX_TCP_SEG) > >>> csum_l4 |= PKT_TX_TCP_CKSUM; > >>> > >>> switch (csum_l4) { > >>> case PKT_TX_UDP_CKSUM: > >>> - hdr->csum_start = cookie->l2_len + cookie->l3_len; > >>> + hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len; > >>> hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum); > >>> hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; > >>> break; > >>> > >>> case PKT_TX_TCP_CKSUM: > >>> - hdr->csum_start = cookie->l2_len + cookie->l3_len; > >>> + hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len; > >>> hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum); > >>> hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; > >>> break; > >>> @@ -650,7 +652,8 @@ virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct > >>> rte_mbuf *cookie) > >>> VIRTIO_NET_HDR_GSO_TCPV6 : > >>> VIRTIO_NET_HDR_GSO_TCPV4; > >>> hdr->gso_size = cookie->tso_segsz; > >>> - hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len; > >>> + hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len + > >>> + cookie->l4_len; > >>> } else { > >>> ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0); > >>> ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0); > >>> -- > >>> 2.20.1 > >> > >> Reviewed-by: Chenbo Xia > >> > > > > I have one comment to mention that from application perspective, it has > > to take care that the driver does not support outer tunnel offload (this > > matches the advertised capabilities). For instance, in case of a vxlan > > tunnel, if the outer checksum needs to be calculated, it has to be done > > by the application. In short, the application can ask to offload the > > inner part if no offload is required on the outer part. > > Yes. It is really complicated. > > Let's name below case (A). > > > Also, since grep "PKT_TX_TUNNEL" in driver/net/ixgbe gives nothing, it > > seems the ixgbe driver does not support the same offload request than > > described in this patch: > > (m->ol_flags & PKT_TX_TUNNEL_MASK) == PKT_TX_TUNNEL_XXXXX > > m->outer_l2_len = outer l2 length > > m->outer_l3_len = outer l3 length > > m->l2_len = outer l4 length + tunnel len + inner l2 len > > m->l3_len = inner l3 len > > m->l4_len = inner l4 len > > True. > > Let's name below case (B). > > > An alternative for doing the same (that would work with ixgbe and > > current virtio) is to give: > > (m->ol_flags & PKT_TX_TUNNEL_MASK) == 0 > > m->l2_len = outer lengths + tunnel len + inner l2 len > > m->l3_len = inner l3 len > > m->l4_len = inner l4 len > > Possible, but I think it is a bit less friendly. > If application supports both cases with and without > outer IPv4 checksum offload, it will require more extra > steps from the application to remove tunnel mask and > collapse outer lengths into l2_len (in addition outer > IPv4 checksum calculation in SW). > > > I think a capability may be missing to differentiate which drivers > > support which mode. > > Yes, something like TX_INNER_CKSUM. > Some drivers already support it, some do not. > > Or, all drivers could be fixed to support both modes > > (and this would make this patch valid). > > I disagree with the point that something is required to > make the patch valid. Before the patch the driver supports > just (B). After the patch the driver supports both (A) and (B). > It makes the driver to support more cases. Yes, I misspoke, I wanted to say that today it is difficult for an application to use this new mode because it does not know which driver supports it. Fixing all drivers would solve the issue without a capability. A drivers/hw supporting one mode can easily support the other one (this patch demonstrates it), so maybe it's not worth having a capability. But yes, this is not a good reason to reject the patch. So: Reviewed-by: Olivier Matz > Please, note that rte_net_intel_cksum_prepare() supports > both (A) and (B) as well.