Commit e59ff2c4 authored Nov 22, 2018 by Jason Wang Committed by David S. Miller Nov 23, 2018

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: 3f93522f ("virtio-net: switch off offloads on demand if possible on XDP set")
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pavel Popa <pashinho1990@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 484afd1b

drivers/net/virtio_net.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -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);
		}

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