virtio-net needs to clear the VIRTIO_NET_F_GUEST_CSUM feature when
loading XDP. The main reason for doing this is that received packets
marked with VIRTIO_NET_HDR_F_NEEDS_CSUM are not compatible with
XDP programs, that is, we cannot guarantee that the csum_{start, offset}
fields are correct after XDP processing.
There is also an existing problem, in the same host vm-vm (eg
[vm]<->[ovs vhost-user]<->[vm]) scenario, loading XDP will cause packet loss.
To solve the above problems, we have discussed in the [1] proposal, and
now try to solve it through the method of reprobing fields suggested
by Jason.
[1] https://lists.oasis-open.org/archives/virtio-dev/202305/msg00318.html
---
v3->v4:
- Rewrite some comments for patch [1/2].
v2->v3:
- Use skb_checksum_setup() instead of virtnet_flow_dissect_udp_tcp(). @Jason Wang
v1->v2:
- Squash v1's patch [1/4] and patch [2/4] into v2's patch [1/3]. @Michael S. Tsirkin
- Some minor modifications.
Heng Qi (2):
virtio-net: support coexistence of XDP and GUEST_CSUM
virtio-net: remove GUEST_CSUM check for XDP
drivers/net/virtio_net.c | 86 ++++++++++++++++++++++++++++++++--------
1 file changed, 70 insertions(+), 16 deletions(-)
--
2.19.1.6.gb485710b
