From nobody Sat May 18 03:35:24 2024 Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5ADB4A0A; Fri, 29 Mar 2024 17:16:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711732616; cv=none; b=QRyq1oYCSSRF1xWQJz4XTmG+/jN/IR7fjhl4yYfXLxxGWkUabc+bd/ewuxS4/5giZMZcFln9tEDHXs0b5byltNOfaZ89oNlMUWhtWtMxtXNO7KK0raIeAocG54/mRfWv/um+M2c6UgjBUlDtu1TYc+3C5PTbe2lwAfT6ohBod0g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711732616; c=relaxed/simple; bh=89L2hT9j8ZH6xSeMx6kL7OhHLwv6S7ZBlgaulX44G44=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=NPB8GEM+Op48eZr50p3oDa9VzeW9F4ewtuLxgOKH5PzugadEyMHBCuyOcMWZEsJC2KucbF6w3HG96xHOtQzAbb91BWprLk7aIxhs0mR2d/R/GvvD+kbDXGf/PeyaUrrFH6k4kLrhm/h8CFBXDc/IA9+Se7D7fP9b0qEf7BiEV/A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.208.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-5688eaf1165so2959601a12.1; Fri, 29 Mar 2024 10:16:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711732613; x=1712337413; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hTKsJeBejVR4zYvKMWuByymkgZTrO1JGV3ZTFtbHxR4=; b=tuJ2ey8+GG+zk96U7tLwCO1SvZTVoEySfkn1oobKXU6nmn51pjw8loJvz+UbnzsxkC f/XGDtokUzlmNEpkSHpAb/WjzzRpRMA8LFNSvZGtk61PJPWLtAuwO4KwbjFF7SRs8VPM vIyU+S+KZyK/vrb9WoddiviowDXizlaoQmX2DSlMGCpPlwplehqtzyTedo8tk33UAZb9 DatxeqByDRJvSVO1QUNY1b/s07PybBaq+4d2iAP3Cm3qiaQO0JNTqMmaD4LNuY9EtCy5 xXNgAyoOPCsEoHARohKVxPw8kLbq6a1SUaeKtrwNJR1Z91sZcFnrLKsBGBDqvmTqzwuZ xItQ== X-Forwarded-Encrypted: i=1; AJvYcCWUs7xFaHMCz26LScjSJINMurrdbHG8cM6OFoIpmYhklOuAkbWd9AhtHrz9zTJkXQma9RkVLAV/OBeB9vOUXfVcxOhxj+Tce2GvnaYFv+zj4bUOkz8U9fcwpgNfr4nhekOk1EyDNR3e4VgyGu8KHsKdfmHDpYGp8QdP+G3/ X-Gm-Message-State: AOJu0YzchfvLFw2ttwBw7Ul/qcvhHKfqL1e+9Vy3sDhQFv7RMWIv+f4z qu37o/x2sWbkXVUwyx5neP6WcaS8RaOD+AgVHkAotKqaFfkNXG0wjVTOlFo7 X-Google-Smtp-Source: AGHT+IEOhTAJ2kk+k1zB7aww/76+35nhb1XyeU1rgxU55vXVijPYjJ5oUVM1Xv+Gs065gM9lKqmFxg== X-Received: by 2002:a05:6402:34d4:b0:56b:9b11:9594 with SMTP id w20-20020a05640234d400b0056b9b119594mr2715983edc.2.1711732613087; Fri, 29 Mar 2024 10:16:53 -0700 (PDT) Received: from localhost (fwdproxy-lla-116.fbsv.net. [2a03:2880:30ff:74::face:b00c]) by smtp.gmail.com with ESMTPSA id u23-20020aa7d897000000b0056ba017ca7fsm2191542edq.87.2024.03.29.10.16.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Mar 2024 10:16:52 -0700 (PDT) From: Breno Leitao To: hengqi@linux.alibaba.com, xuanzhuo@linux.alibaba.com, "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andrew Melnychenko Cc: rbc@meta.com, riel@surriel.com, stable@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux.dev (open list:VIRTIO CORE AND NET DRIVERS), netdev@vger.kernel.org (open list:NETWORKING DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH net v3] virtio_net: Do not send RSS key if it is not supported Date: Fri, 29 Mar 2024 10:16:41 -0700 Message-ID: <20240329171641.366520-1-leitao@debian.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop. Running the following command in any QEMU virtual machine with virtionet will reproduce this problem: # ethtool -X eth0 hfunc toeplitz This is how the problem happens: 1) ethtool_set_rxfh() calls virtnet_set_rxfh() 2) virtnet_set_rxfh() calls virtnet_commit_rss_command() 3) virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather 4) Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size =3D=3D 0. sg_buf_size =3D vi->rss_key_size; 5) This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function): if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed"); 6) virtio_error() (also QEMU function) set the device as broken vdev->broken =3D true; 7) Qemu bails out, and do not repond this crazy kernel. 8) The kernel is waiting for the response to come back (function virtnet_send_command()) 9) The kernel is waiting doing the following : while (!virtqueue_get_buf(vi->cvq, &tmp) && !virtqueue_is_broken(vi->cvq)) cpu_relax(); 10) None of the following functions above is true, thus, the kernel loops here forever. Keeping in mind that virtqueue_is_broken() does not look at the qemu `vdev->broken`, so, it never realizes that the vitio is broken at QEMU side. Fix it by not sending RSS commands if the feature is not available in the device. Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.") Cc: stable@vger.kernel.org Cc: qemu-devel@nongnu.org Signed-off-by: Breno Leitao Reviewed-by: Heng Qi --- Changelog: V2: * Moved from creating a valid packet, by rejecting the request completely V3: * Got some good feedback from and Xuan Zhuo and Heng Qi, and reworked the rejection path. --- drivers/net/virtio_net.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index c22d1118a133..c4a21ec51adf 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3807,6 +3807,7 @@ static int virtnet_set_rxfh(struct net_device *dev, struct netlink_ext_ack *extack) { struct virtnet_info *vi =3D netdev_priv(dev); + bool update =3D false; int i; =20 if (rxfh->hfunc !=3D ETH_RSS_HASH_NO_CHANGE && @@ -3814,13 +3815,24 @@ static int virtnet_set_rxfh(struct net_device *dev, return -EOPNOTSUPP; =20 if (rxfh->indir) { + if (!vi->has_rss) + return -EOPNOTSUPP; + for (i =3D 0; i < vi->rss_indir_table_size; ++i) vi->ctrl->rss.indirection_table[i] =3D rxfh->indir[i]; + update =3D true; } - if (rxfh->key) + + if (rxfh->key) { + if (!vi->has_rss && !vi->has_rss_hash_report) + return -EOPNOTSUPP; + memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size); + update =3D true; + } =20 - virtnet_commit_rss_command(vi); + if (update) + virtnet_commit_rss_command(vi); =20 return 0; } @@ -4729,13 +4741,15 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT)) vi->has_rss_hash_report =3D true; =20 - if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) + if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) { vi->has_rss =3D true; =20 - if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size =3D virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); + } + + if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_key_size =3D virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size= )); =20 --=20 2.43.0