From: John Fastabend <john.fastab...@gmail.com>
Date: Mon, 19 Dec 2016 09:50:57 -0800
> On 16-12-19 07:05 AM, Jakub Kicinski wrote:
>> commit 17bedab27231 ("bpf: xdp: Allow head adjustment in XDP prog")
>> added a new XDP helper to prepend and remove data from a frame.
>> Make virtio_net reject programs making use of this helper until
>> proper support is added.
>>
>> Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
>> ---
>> drivers/net/virtio_net.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 08327e005ccc..db761f37783e 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -1677,6 +1677,11 @@ static int virtnet_xdp_set(struct net_device *dev,
>> struct bpf_prog *prog)
>> u16 xdp_qp = 0, curr_qp;
>> int i, err;
>>
>> + if (prog && prog->xdp_adjust_head) {
>> + netdev_warn(dev, "Does not support bpf_xdp_adjust_head()\n");
>> + return -EOPNOTSUPP;
>> + }
>> +
>> if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
>> virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6)) {
>> netdev_warn(dev, "can't set XDP while host is implementing LRO,
>> disable LRO first\n");
>>
>
> Acked-by: John Fastabend <john.r.fastab...@intel.com>
>
> Thanks patch looks good. Alternatively we could push a "bug fix" to
> support the adjust header feature depending on how DaveM and MST feel
> about that. I don't have a strong opinion but I have the patch on my
> queue it just needs some more testing. The adjust header bits were
> merged in between some of the later versions of the patch which is how
> this check got missed.
I would like to avoid inconsistent XDP feature support amongst drivers
as much as possible.
