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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C4DC9C433DB for ; Mon, 1 Mar 2021 18:54:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85F7964DEE for ; Mon, 1 Mar 2021 18:54:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240290AbhCASyO (ORCPT ); Mon, 1 Mar 2021 13:54:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47016 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240634AbhCASsh (ORCPT ); Mon, 1 Mar 2021 13:48:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614624430; 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=S53kYgBrvO58mkF8bhEVdcsH3v8DHU2I+2HExMYGeWc=; b=ViJVaCglaeTarrEa+UCsg3bk3eqVC1QTZJO46XTtdkwc9J1QH1zdjDcrgv477GeLCYGCVa chp8BrQ48U/nt3t/cp9rvZ+v7gXsQvQHtXi2Cb4SPCtzogtx36PwMjjGMqBt3vIQbdvhr0 x/ns5hneleAHEO/H8q7aqq7SRc4RrU0= 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-269-bg6BCiVaMlizEDKWbzxDyg-1; Mon, 01 Mar 2021 13:47:06 -0500 X-MC-Unique: bg6BCiVaMlizEDKWbzxDyg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 265E1803F47; Mon, 1 Mar 2021 18:47:05 +0000 (UTC) Received: from carbon (unknown [10.36.110.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id A9F9710013D7; Mon, 1 Mar 2021 18:46:55 +0000 (UTC) Date: Mon, 1 Mar 2021 19:46:54 +0100 From: Jesper Dangaard Brouer To: netdev , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Jesse Brandeburg , Tony Nguyen , Marek Majtyka Cc: intel-wired-lan , Jakub Kicinski , Alexei Starovoitov , Maciej Fijalkowski , Tony Brelinski , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , brouer@redhat.com Subject: Re: Driver i40e have XDP-redirect bug Message-ID: <20210301194654.10513eb2@carbon> In-Reply-To: <20210301131832.0d765179@carbon> References: <20210301131832.0d765179@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 1 Mar 2021 13:18:32 +0100 Jesper Dangaard Brouer wrote: > Hi i40e-people + XDP-feature-people, > > The driver i40e have a XDP-redirect bug, where is it partly broken. It can > transmit a redirected xdp_frame (from another driver). But broken when > redirecting a xdp_frame that is received by the driver itself. > > This reminds me about lacking XDP-features, as this "state" is actually > "supported" (for Intel drivers), when running in 'legacy-rx' mode. This can > be configured (via: 'ethtool --set-priv-flags i40e2 legacy-rx on'). When > running in 'legacy-rx' mode the headroom is zero, which means that xdp_frame > cannot be created as it is stored in this headroom, but an XDP-prog can > still run a (DDoS) filter. (Hint grepping after xdp_redirect stats is not enough). > > The BUG I experience *is* that headroom is zero, but 'legacy-rx' mode is off: > > $ ethtool --show-priv-flags i40e2 | grep legacy-rx > legacy-rx : off > > This is clearly a driver initialization bug as the headroom should not > be zero in this configuration. Further indication that this is related > to init order: If while xdp_redirect is running, I change RX-ring size > (e.g. 'ethtool -G i40e2 rx 1024') then redirect starts working again. > > > I will continue to find the offending commit... (to-be-continued) > (p.s. testing on net-next on top of commit d310ec03a34e92). The problem is in this commit f7bb0d71d658 ("i40e: store the result of i40e_rx_offset() onto i40e_ring"), and below patch fix the issue for me. I am in dialog with Maciej and he will send a proper fix. The commit is fairly new, but have reached Linus'es tree: $ git describe f7bb0d71d658 --contains v5.12-rc1~200^2~54^2~2 -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer [PATCH] i40e: fix packet headroom From: Jesper Dangaard Brouer Fixes: f7bb0d71d658 ("i40e: store the result of i40e_rx_offset() onto i40e_ring") Signed-off-by: Jesper Dangaard Brouer --- drivers/net/ethernet/intel/i40e/i40e_main.c | 14 ++++++++++++++ drivers/net/ethernet/intel/i40e/i40e_txrx.c | 12 ------------ 2 files changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 8bb8eb65add9..4c0b4bc38338 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -3259,6 +3259,17 @@ static int i40e_configure_tx_ring(struct i40e_ring *ring) return 0; } +/** + * i40e_rx_offset - Return expected offset into page to access data + * @rx_ring: Ring we are requesting offset of + * + * Returns the offset value for ring into the data buffer. + */ +static unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) +{ + return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; +} + /** * i40e_configure_rx_ring - Configure a receive ring context * @ring: The Rx ring to configure @@ -3370,6 +3381,9 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring) else set_ring_build_skb_enabled(ring); + ring->rx_offset = i40e_rx_offset(ring); + pr_info("XXX %s() ring->rx_offset = %d\n", __func__, ring->rx_offset); + /* cache tail for quicker writes, and clear the reg before use */ ring->tail = hw->hw_addr + I40E_QRX_TAIL(pf_q); writel(0, ring->tail); diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index f6f1af94cca0..e398b8ac2a85 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1569,17 +1569,6 @@ void i40e_free_rx_resources(struct i40e_ring *rx_ring) } } -/** - * i40e_rx_offset - Return expected offset into page to access data - * @rx_ring: Ring we are requesting offset of - * - * Returns the offset value for ring into the data buffer. - */ -static unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) -{ - return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; -} - /** * i40e_setup_rx_descriptors - Allocate Rx descriptors * @rx_ring: Rx descriptor ring (for a specific queue) to setup @@ -1608,7 +1597,6 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring) rx_ring->next_to_alloc = 0; rx_ring->next_to_clean = 0; rx_ring->next_to_use = 0; - rx_ring->rx_offset = i40e_rx_offset(rx_ring); /* XDP RX-queue info only needed for RX rings exposed to XDP */ if (rx_ring->vsi->type == I40E_VSI_MAIN) {