[RFC PATCH 2/9] virtio_net: set up xdp for multi buffer packets

Heng Qi
2022-11-22T07:44:05Z

When the xdp program sets xdp.frags, which means it can process
multi-buffer packets, so we continue to open xdp support when
features such as GRO_HW are negotiated.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
drivers/net/virtio_net.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c5046d21b281..8f7d207d58d6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3080,14 +3080,21 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
u16 xdp_qp = 0, curr_qp;
int i, err;

- if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)
- && (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) ||
- virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM))) {
- NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing GRO_HW/CSUM, disable GRO_HW/CSUM first");
- return -EOPNOTSUPP;
+ if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM)) {
+ NL_SET_ERR_MSG_MOD(extack, "Can't set XDP without frags while guest is implementing GUEST_CSUM");
+ return -EOPNOTSUPP;
+ }
+
+ if (prog && !prog->aux->xdp_has_frags) {
+ if (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 without frags while guest is implementing GUEST_GRO_HW");
+ return -EOPNOTSUPP;
+ }
+ }
}

if (vi->mergeable_rx_bufs && !vi->any_header_sg) {
@@ -3095,8 +3102,8 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
return -EINVAL;
}

- if (dev->mtu > max_sz) {
- NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP");
+ if (prog && !prog->aux->xdp_has_frags && dev->mtu > max_sz) {
+ NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP without frags");
netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz);
return -EINVAL;
}
@@ -3218,9 +3225,6 @@ static int virtnet_set_features(struct net_device *dev,
int err;

if ((dev->features ^ features) & NETIF_F_GRO_HW) {
- if (vi->xdp_enabled)
- return -EBUSY;
-
if (features & NETIF_F_GRO_HW)
offloads = vi->guest_offloads_capable;
else
--
2.19.1.6.gb485710b