From patchwork Mon Aug 15 09:26:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Zhu, Lingshan" X-Patchwork-Id: 12943375 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5BDBC00140 for ; Mon, 15 Aug 2022 09:35:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242082AbiHOJfA (ORCPT ); Mon, 15 Aug 2022 05:35:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242022AbiHOJe5 (ORCPT ); Mon, 15 Aug 2022 05:34:57 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E524D1CB35; Mon, 15 Aug 2022 02:34:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660556096; x=1692092096; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=eocacwuC7jptNZ6boMwO2FAPSm+fSfP6r/33VIYdhHg=; b=Mi8sd6EwB1b1TWnYt4p9RT06D5a1wsSmTikBWt37n+UnrICJjzxGEpPV 7OicPnsrbg3pmORvjgqisltF3uD41cgAfoB8y66CRXCjo7KpCZ22OJFW/ sZ0W2tCsnw9iedgU+/eBIQVfpuqRWMPRJ3oO+N/HFOgAsOwXToBGR+zK4 s+pTuKYIwdnnnXUADU+XlzyHLXcmlS8x25LrA+0DqAOWkEBpFjxYjtHTX I62FlANj5bKYQ2CvR6O+ziymZsmB973eeEoc+JVScMFs4IPxc9xUpj8vt c8UqfvMJ8hoaAXjScd3d56EB8tg3jU+M9+hBvxJ1j6/GwqwLvncNi1UMv w==; X-IronPort-AV: E=McAfee;i="6400,9594,10439"; a="353668404" X-IronPort-AV: E=Sophos;i="5.93,238,1654585200"; d="scan'208";a="353668404" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2022 02:34:55 -0700 X-IronPort-AV: E=Sophos;i="5.93,238,1654585200"; d="scan'208";a="666604169" Received: from unknown (HELO localhost.localdomain.bj.intel.com) ([10.240.193.73]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2022 02:34:53 -0700 From: Zhu Lingshan To: jasowang@redhat.com, mst@redhat.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, parav@nvidia.com, xieyongji@bytedance.com, gautam.dawar@amd.com, Zhu Lingshan Subject: [PATCH 2/2] vDPA: conditionally read fields in virtio-net dev Date: Mon, 15 Aug 2022 17:26:38 +0800 Message-Id: <20220815092638.504528-3-lingshan.zhu@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220815092638.504528-1-lingshan.zhu@intel.com> References: <20220815092638.504528-1-lingshan.zhu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Some fields of virtio-net device config space are conditional on the feature bits, the spec says: "The mac address field always exists (though is only valid if VIRTIO_NET_F_MAC is set)" "max_virtqueue_pairs only exists if VIRTIO_NET_F_MQ or VIRTIO_NET_F_RSS is set" "mtu only exists if VIRTIO_NET_F_MTU is set" so we should read MTU, MAC and MQ in the device config space only when these feature bits are offered. For MQ, if both VIRTIO_NET_F_MQ and VIRTIO_NET_F_RSS are not set, the virtio device should have one queue pair as default value, so when userspace querying queue pair numbers, it should return mq=1 than zero. For MTU, if VIRTIO_NET_F_MTU is not set, we should not read MTU from the device config sapce. RFC894 says:"The minimum length of the data field of a packet sent over an Ethernet is 1500 octets, thus the maximum length of an IP datagram sent over an Ethernet is 1500 octets. Implementations are encouraged to support full-length packets" virtio spec says:"The virtio network device is a virtual ethernet card", so the default MTU value should be 1500 for virtio-net. For MAC, the spec says:"If the VIRTIO_NET_F_MAC feature bit is set, the configuration space mac entry indicates the “physical” address of the network card, otherwise the driver would typically generate a random local MAC address." So there is no default MAC address if VIRTIO_NET_F_MAC not set. This commits introduces functions vdpa_dev_net_mtu_config_fill() and vdpa_dev_net_mac_config_fill() to fill MTU and MAC. It also fixes vdpa_dev_net_mq_config_fill() to report correct MQ when _F_MQ is not present. These functions should check devices features than driver features, and struct vdpa_device is not needed as a parameter The test & userspace tool output: Feature bit VIRTIO_NET_F_MTU, VIRTIO_NET_F_RSS, VIRTIO_NET_F_MQ and VIRTIO_NET_F_MAC can be mask out by hardcode. However, it is challenging to "disable" the related fields in the HW device config space, so let's just assume the values are meaningless if the feature bits are not set. Before this change, when feature bits for RSS, MQ, MTU and MAC are not set, iproute2 output: $vdpa vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false mtu 1500 negotiated_features without this commit, function vdpa_dev_net_config_fill() reads all config space fields unconditionally, so let's assume the MAC and MTU are meaningless, and it checks MQ with driver_features, so we don't see max_vq_pairs. After applying this commit, when feature bits for MQ, RSS, MAC and MTU are not set,iproute2 output: $vdpa dev config show vdpa0 vdpa0: link up link_announce false max_vq_pairs 1 mtu 1500 negotiated_features As explained above: Here is no MAC, because VIRTIO_NET_F_MAC is not set, and there is no default value for MAC. It shows max_vq_paris = 1 because even without MQ feature, a functional virtio-net must have one queue pair. mtu = 1500 is the default value as ethernet required. This commit also add supplementary comments for __virtio16_to_cpu(true, xxx) operations in vdpa_dev_net_config_fill() and vdpa_fill_stats_rec() Signed-off-by: Zhu Lingshan --- drivers/vdpa/vdpa.c | 60 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 47 insertions(+), 13 deletions(-) diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index efb55a06e961..a74660b98979 100644 --- a/drivers/vdpa/vdpa.c +++ b/drivers/vdpa/vdpa.c @@ -801,19 +801,44 @@ static int vdpa_nl_cmd_dev_get_dumpit(struct sk_buff *msg, struct netlink_callba return msg->len; } -static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev, - struct sk_buff *msg, u64 features, +static int vdpa_dev_net_mq_config_fill(struct sk_buff *msg, u64 features, const struct virtio_net_config *config) { u16 val_u16; - if ((features & BIT_ULL(VIRTIO_NET_F_MQ)) == 0) - return 0; + if ((features & BIT_ULL(VIRTIO_NET_F_MQ)) == 0 && + (features & BIT_ULL(VIRTIO_NET_F_RSS)) == 0) + val_u16 = 1; + else + val_u16 = __virtio16_to_cpu(true, config->max_virtqueue_pairs); - val_u16 = le16_to_cpu(config->max_virtqueue_pairs); return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, val_u16); } +static int vdpa_dev_net_mtu_config_fill(struct sk_buff *msg, u64 features, + const struct virtio_net_config *config) +{ + u16 val_u16; + + if ((features & BIT_ULL(VIRTIO_NET_F_MTU)) == 0) + val_u16 = 1500; + else + val_u16 = __virtio16_to_cpu(true, config->mtu); + + return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16); +} + +static int vdpa_dev_net_mac_config_fill(struct sk_buff *msg, u64 features, + const struct virtio_net_config *config) +{ + if ((features & BIT_ULL(VIRTIO_NET_F_MAC)) == 0) + return 0; + else + return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, + sizeof(config->mac), config->mac); +} + + static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg) { struct virtio_net_config config = {}; @@ -822,18 +847,16 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config)); - if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac), - config.mac)) - return -EMSGSIZE; + /* + * Assume little endian for now, userspace can tweak this for + * legacy guest support. + */ + val_u16 = __virtio16_to_cpu(true, config.status); val_u16 = __virtio16_to_cpu(true, config.status); if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16)) return -EMSGSIZE; - val_u16 = __virtio16_to_cpu(true, config.mtu); - if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16)) - return -EMSGSIZE; - features_driver = vdev->config->get_driver_features(vdev); if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver, VDPA_ATTR_PAD)) @@ -846,7 +869,13 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms VDPA_ATTR_PAD)) return -EMSGSIZE; - return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver, &config); + if (vdpa_dev_net_mac_config_fill(msg, features_device, &config)) + return -EMSGSIZE; + + if (vdpa_dev_net_mtu_config_fill(msg, features_device, &config)) + return -EMSGSIZE; + + return vdpa_dev_net_mq_config_fill(msg, features_device, &config); } static int @@ -914,6 +943,11 @@ static int vdpa_fill_stats_rec(struct vdpa_device *vdev, struct sk_buff *msg, } vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config)); + /* + * Assume little endian for now, userspace can tweak this for + * legacy guest support. + */ + max_vqp = __virtio16_to_cpu(true, config.max_virtqueue_pairs); if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, max_vqp)) return -EMSGSIZE;