From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5D97E12C805; Tue, 30 Apr 2024 11:28:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714476528; cv=none; b=ZHXehXTRVjC3KWWVsAhM2moW1Ykz+WfPJ+zT1UK5+kcUQstvOLTtIudaukdV7QfTTxFgwXwZC3IajFrp0v+EyZGhIVdRFh5+sB/MrhPoENZhfN9rZZSbAQ3z1Kq0KYhNeyy3kjAkrxYK9QOePk8hojoG4l/3YudTAbZsY4oaZKc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714476528; c=relaxed/simple; bh=Y6scN/f6gfKI80HAF7k6NMVT4Ov0pD6EG38opDcY3eg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=u5XYuz7c0o5MQgfWsvNc8T+cIgJc5UoX0VUNFzZKlTmn/reie+rleq+r8MXKNNyUaSM380YvaXNf4W94qZZq5/mcLmJsQQ4H+vjG+oxVaWBh5tDre/NkRohmS3aicyaYR8Vy1sZUCa9RZl4iUZIbhKWvlFMyTjz2+t10aLz0KFc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YMp2AXho; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YMp2AXho" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4C6AC2BBFC; Tue, 30 Apr 2024 11:28:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1714476528; bh=Y6scN/f6gfKI80HAF7k6NMVT4Ov0pD6EG38opDcY3eg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YMp2AXho3G2MY70z85QwWyt0CaYdk2uD+089ahe57TrdW4YJ2b3gBKUKII9WGdV+D HB7Lp2latqnx/okeWDJEG5jYyNrUFtdt8n22V1KJfWhZoR9hEav3qAJwo+3GcfkQjM kZVhCiJFpebZ5CeQRVUw2MH0sSInCzc/JOeKlbNA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, qemu-devel@nongnu.org, Breno Leitao , Heng Qi , Xuan Zhuo , "David S. Miller" , Konstantin Ovsepian Subject: [PATCH 6.1 061/110] virtio_net: Do not send RSS key if it is not supported Date: Tue, 30 Apr 2024 12:40:30 +0200 Message-ID: <20240430103049.368332554@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240430103047.561802595@linuxfoundation.org> References: <20240430103047.561802595@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao commit 059a49aa2e25c58f90b50151f109dd3c4cdb3a47 upstream. 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 == 0. sg_buf_size = 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 = 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 Reviewed-by: Xuan Zhuo Signed-off-by: David S. Miller Signed-off-by: Konstantin Ovsepian Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2948,19 +2948,35 @@ static int virtnet_get_rxfh(struct net_d static int virtnet_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key, const u8 hfunc) { struct virtnet_info *vi = netdev_priv(dev); + bool update = false; int i; if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP; if (indir) { + if (!vi->has_rss) + return -EOPNOTSUPP; + for (i = 0; i < vi->rss_indir_table_size; ++i) vi->ctrl->rss.indirection_table[i] = indir[i]; + update = true; } - if (key) + + if (key) { + /* If either _F_HASH_REPORT or _F_RSS are negotiated, the + * device provides hash calculation capabilities, that is, + * hash_key is configured. + */ + if (!vi->has_rss && !vi->has_rss_hash_report) + return -EOPNOTSUPP; + memcpy(vi->ctrl->rss.key, key, vi->rss_key_size); + update = true; + } - virtnet_commit_rss_command(vi); + if (update) + virtnet_commit_rss_command(vi); return 0; } @@ -3852,13 +3868,15 @@ static int virtnet_probe(struct virtio_d if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT)) vi->has_rss_hash_report = true; - if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) + if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) { vi->has_rss = true; - if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = 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 = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));