From e59ff2c49ae16e1d179de679aca81405829aee6c Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 22 Nov 2018 14:36:30 +0800 Subject: virtio-net: disable guest csum during XDP set We don't disable VIRTIO_NET_F_GUEST_CSUM if XDP was set. This means we can receive partial csumed packets with metadata kept in the vnet_hdr. This may have several side effects: - It could be overridden by header adjustment, thus is might be not correct after XDP processing. - There's no way to pass such metadata information through XDP_REDIRECT to another driver. - XDP does not support checksum offload right now. So simply disable guest csum if possible in this the case of XDP. Fixes: 3f93522ffab2d ("virtio-net: switch off offloads on demand if possible on XDP set") Reported-by: Jesper Dangaard Brouer Cc: Jesper Dangaard Brouer Cc: Pavel Popa Cc: David Ahern Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'drivers/net/virtio_net.c') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3e2c041d76ac..9b5ace538824 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -70,7 +70,8 @@ static const unsigned long guest_offloads[] = { VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, VIRTIO_NET_F_GUEST_ECN, - VIRTIO_NET_F_GUEST_UFO + VIRTIO_NET_F_GUEST_UFO, + VIRTIO_NET_F_GUEST_CSUM }; struct virtnet_stat_desc { @@ -2334,9 +2335,6 @@ static int virtnet_clear_guest_offloads(struct virtnet_info *vi) if (!vi->guest_offloads) return 0; - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM)) - offloads = 1ULL << VIRTIO_NET_F_GUEST_CSUM; - return virtnet_set_guest_offloads(vi, offloads); } @@ -2346,8 +2344,6 @@ static int virtnet_restore_guest_offloads(struct virtnet_info *vi) if (!vi->guest_offloads) return 0; - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM)) - offloads |= 1ULL << VIRTIO_NET_F_GUEST_CSUM; return virtnet_set_guest_offloads(vi, offloads); } -- cgit From 18ba58e1c234ea1a2d9835ac8c1735d965ce4640 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 22 Nov 2018 14:36:31 +0800 Subject: virtio-net: fail XDP set if guest csum is negotiated We don't support partial csumed packet since its metadata will be lost or incorrect during XDP processing. So fail the XDP set if guest_csum feature is negotiated. Fixes: f600b6905015 ("virtio_net: Add XDP support") Reported-by: Jesper Dangaard Brouer Cc: Jesper Dangaard Brouer Cc: Pavel Popa Cc: David Ahern Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/net/virtio_net.c') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9b5ace538824..cecfd77c9f3c 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2361,8 +2361,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog, && (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) || virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) || virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) || - virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO))) { - NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing LRO, disable LRO first"); + virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) || + virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM))) { + NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing LRO/CSUM, disable LRO/CSUM first"); return -EOPNOTSUPP; } -- cgit From 436c9453a1ac0944b82870ef2e0d9be956b396d9 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 29 Nov 2018 13:53:16 +0800 Subject: virtio-net: keep vnet header zeroed after processing XDP We copy vnet header unconditionally in page_to_skb() this is wrong since XDP may modify the packet data. So let's keep a zeroed vnet header for not confusing the conversion between vnet header and skb metadata. In the future, we should able to detect whether or not the packet was modified and keep using the vnet header when packet was not touched. Fixes: f600b6905015 ("virtio_net: Add XDP support") Reported-by: Pavel Popa Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'drivers/net/virtio_net.c') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index cecfd77c9f3c..ea672145f6a6 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -365,7 +365,8 @@ static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx) static struct sk_buff *page_to_skb(struct virtnet_info *vi, struct receive_queue *rq, struct page *page, unsigned int offset, - unsigned int len, unsigned int truesize) + unsigned int len, unsigned int truesize, + bool hdr_valid) { struct sk_buff *skb; struct virtio_net_hdr_mrg_rxbuf *hdr; @@ -387,7 +388,8 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, else hdr_padded_len = sizeof(struct padded_vnet_hdr); - memcpy(hdr, p, hdr_len); + if (hdr_valid) + memcpy(hdr, p, hdr_len); len -= hdr_len; offset += hdr_padded_len; @@ -739,7 +741,8 @@ static struct sk_buff *receive_big(struct net_device *dev, struct virtnet_rq_stats *stats) { struct page *page = buf; - struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE); + struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, + PAGE_SIZE, true); stats->bytes += len - vi->hdr_len; if (unlikely(!skb)) @@ -842,7 +845,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, rcu_read_unlock(); put_page(page); head_skb = page_to_skb(vi, rq, xdp_page, - offset, len, PAGE_SIZE); + offset, len, + PAGE_SIZE, false); return head_skb; } break; @@ -898,7 +902,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, goto err_skb; } - head_skb = page_to_skb(vi, rq, page, offset, len, truesize); + head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog); curr_skb = head_skb; if (unlikely(!curr_skb)) -- cgit