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 D0E582FD7BC; Tue, 31 Mar 2026 17:01:32 +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=1774976492; cv=none; b=ANjT+HnznaqjexDvZrUqj30bazvNCNRuNxepxf9DiJ0kcl2b4Gw9M/Un2by+YIotCBjwHqb9mpFWVEsmXu8+uwGyak7jgbFZLzexwohYt9BoP3lEjD4Vyf1bJkORGGKidaPbV+HKd/n1f2hJd9T1VMysofOdzk9JEtS5+A6DMRw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976492; c=relaxed/simple; bh=IlBUifvO/s4XKuIfZk1kYhsi11XuctpnTAQ6M0jGaUY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dtYN1RUKA+xjAxWkGmPjYLPATrGhQ12S0K8pD96upvEVQsOm5bPZpK2eGlaX3UlREf04O6cXJF01uh9GWq/nek16g0XuwLOlyqF+kBiuIW4m13j+XoWLZxo3qZyJiMn8ih1ygiBg3gXUg6eiMMaOHSTUufPl/nJ8kqUc+3zS4oY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Tp10pFu7; 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="Tp10pFu7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51F9AC19423; Tue, 31 Mar 2026 17:01:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774976492; bh=IlBUifvO/s4XKuIfZk1kYhsi11XuctpnTAQ6M0jGaUY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tp10pFu7tpEx0is4q3GAvcc7WZujNUG1mN4pJnSbeRzpn9EVBE6UeTG2B7gBrt2TD Dwls+Dx0odnSuPzPDhGf9/ezeLR5Y8FZzjOxfR3FN4HA7zRDJuD3rCH6PIQkvhusNV 2NLwwst8fOFM4iUzcj9tOhVI9XMd6+DaOdlfbmvg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xuan Zhuo , "Michael S. Tsirkin" , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 113/309] virtio-net: correct hdr_len handling for VIRTIO_NET_F_GUEST_HDRLEN Date: Tue, 31 Mar 2026 18:20:16 +0200 Message-ID: <20260331161757.645439547@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161753.468533260@linuxfoundation.org> References: <20260331161753.468533260@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xuan Zhuo [ Upstream commit 38ec410b99a5ee6566f75650ce3d4fd632940fd0 ] The commit be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") introduces support for the VIRTIO_NET_F_GUEST_HDRLEN feature in virtio-net. This feature requires virtio-net to set hdr_len to the actual header length of the packet when transmitting, the number of bytes from the start of the packet to the beginning of the transport-layer payload. However, in practice, hdr_len was being set using skb_headlen(skb), which is clearly incorrect. This commit fixes that issue. Fixes: be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") Signed-off-by: Xuan Zhuo Link: https://patch.msgid.link/20260320021818.111741-2-xuanzhuo@linux.alibaba.com Acked-by: Michael S. Tsirkin Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/tun_vnet.h | 2 +- drivers/net/virtio_net.c | 6 +++++- include/linux/virtio_net.h | 34 ++++++++++++++++++++++++++++++---- 3 files changed, 36 insertions(+), 6 deletions(-) diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h index a5f93b6c4482c..fa5cab9d3e55c 100644 --- a/drivers/net/tun_vnet.h +++ b/drivers/net/tun_vnet.h @@ -244,7 +244,7 @@ tun_vnet_hdr_tnl_from_skb(unsigned int flags, if (virtio_net_hdr_tnl_from_skb(skb, tnl_hdr, has_tnl_offload, tun_vnet_is_little_endian(flags), - vlan_hlen, true)) { + vlan_hlen, true, false)) { struct virtio_net_hdr_v1 *hdr = &tnl_hdr->hash_hdr.hdr; struct skb_shared_info *sinfo = skb_shinfo(skb); diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index b67dbe346c807..9f855d196ae8f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3326,8 +3326,12 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) struct virtio_net_hdr_v1_hash_tunnel *hdr; int num_sg; unsigned hdr_len = vi->hdr_len; + bool feature_hdrlen; bool can_push; + feature_hdrlen = virtio_has_feature(vi->vdev, + VIRTIO_NET_F_GUEST_HDRLEN); + pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); /* Make sure it's safe to cast between formats */ @@ -3347,7 +3351,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) if (virtio_net_hdr_tnl_from_skb(skb, hdr, vi->tx_tnl, virtio_is_little_endian(vi->vdev), 0, - false)) + false, feature_hdrlen)) return -EPROTO; if (vi->mergeable_rx_bufs) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 75dabb763c650..361b60c8be680 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -207,6 +207,23 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, return __virtio_net_hdr_to_skb(skb, hdr, little_endian, hdr->gso_type); } +/* This function must be called after virtio_net_hdr_from_skb(). */ +static inline void __virtio_net_set_hdrlen(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian) +{ + u16 hdr_len; + + hdr_len = skb_transport_offset(skb); + + if (hdr->gso_type == VIRTIO_NET_HDR_GSO_UDP_L4) + hdr_len += sizeof(struct udphdr); + else + hdr_len += tcp_hdrlen(skb); + + hdr->hdr_len = __cpu_to_virtio16(little_endian, hdr_len); +} + static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, struct virtio_net_hdr *hdr, bool little_endian, @@ -385,7 +402,8 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, bool tnl_hdr_negotiated, bool little_endian, int vlan_hlen, - bool has_data_valid) + bool has_data_valid, + bool feature_hdrlen) { struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)vhdr; unsigned int inner_nh, outer_th; @@ -394,9 +412,17 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM); - if (!tnl_gso_type) - return virtio_net_hdr_from_skb(skb, hdr, little_endian, - has_data_valid, vlan_hlen); + if (!tnl_gso_type) { + ret = virtio_net_hdr_from_skb(skb, hdr, little_endian, + has_data_valid, vlan_hlen); + if (ret) + return ret; + + if (feature_hdrlen && hdr->hdr_len) + __virtio_net_set_hdrlen(skb, hdr, little_endian); + + return ret; + } /* Tunnel support not negotiated but skb ask for it. */ if (!tnl_hdr_negotiated) -- 2.51.0