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 D0DB174C0C; Mon, 15 Apr 2024 14:26:12 +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=1713191172; cv=none; b=nAfuUxyMwwOzP5Nyxlj1+lF1z+O6d1sCvNWqkXEMCaXAGk2SWDWOrehoeuYidKD1cK9Ss7nZZaVh9NyLIPVmuJxhihLdKrepLpXtCu3H0VIIlRafWoEf7aBC0w3m4BhcNWUmBnJyNMpWdVWFiX6dhVNsWrN1kIrHi4uvq2LYHjo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713191172; c=relaxed/simple; bh=ljaw1E3qFIqt2x4A+U9bPaVD6pkQHPufn25O4pnueYk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ksw2CXYwxLm0W+7p7M0jyI1X+oCw2uVFmMx48DXctWV/504UH70AgFt1HrcI7TW0XWDbfOWFc/lJhJKwCNtf2/9FmuNL152s000RGDCY5PEZSnHn1ZQnUXWB1SNsKPEGw1BUn7+RIFYXdYDX1lLajimSQDuV32DlfEkR8OVQ6S8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nU9Zczi7; 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="nU9Zczi7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E8EBC113CC; Mon, 15 Apr 2024 14:26:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713191172; bh=ljaw1E3qFIqt2x4A+U9bPaVD6pkQHPufn25O4pnueYk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nU9Zczi7FTOEfjZlClZUiYn0FcpoGgKphKbYwoIAQv8iYgpJJ/aX9MLQ0gqnWjgbZ WMoP0rvFRZHHVwmmLWvXfRuw8gU808XaXuD8MeQJEABoYXxUibHXLJRhRfixZ5m86g KL4r7zIbshUq24B9mjzSxOwkoBz3yYA6ILGMYKpU= 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" Subject: [PATCH 6.8 008/172] virtio_net: Do not send RSS key if it is not supported Date: Mon, 15 Apr 2024 16:18:27 +0200 Message-ID: <20240415142000.227047251@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240415141959.976094777@linuxfoundation.org> References: <20240415141959.976094777@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 6.8-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: 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 @@ -3768,6 +3768,7 @@ static int virtnet_set_rxfh(struct net_d struct netlink_ext_ack *extack) { struct virtnet_info *vi = netdev_priv(dev); + bool update = false; int i; if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && @@ -3775,13 +3776,28 @@ static int virtnet_set_rxfh(struct net_d return -EOPNOTSUPP; if (rxfh->indir) { + if (!vi->has_rss) + return -EOPNOTSUPP; + for (i = 0; i < vi->rss_indir_table_size; ++i) vi->ctrl->rss.indirection_table[i] = rxfh->indir[i]; + update = true; } - if (rxfh->key) + + if (rxfh->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, rxfh->key, vi->rss_key_size); + update = true; + } - virtnet_commit_rss_command(vi); + if (update) + virtnet_commit_rss_command(vi); return 0; } @@ -4686,13 +4702,15 @@ 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));