> On 4/15/23 12:10 AM, Lorenzo Bianconi wrote:
> > > On 4/14/23 11:21 PM, Lorenzo Bianconi wrote:
> > > > NETDEV_XDP_ACT_NDO_XMIT is not enabled by default for veth driver but it
> > > > depends on the device configuration. Fix XDP_REDIRECT xdp-features in
> > > > xdp_bonding selftest loading a dummy XDP program on veth2_2 device.
> > > >
> > > > Fixes: fccca038f300 ("veth: take into account device reconfiguration for xdp_features flag")
> > >
> > > Hm, does that mean we're changing^breaking existing user behavior iff after
> > > fccca038f300 you can only make it work by loading dummy prog?
> >
> > nope, even before in order to enable ndo_xdp_xmit for veth you should load a dummy
> > program on the device peer or enable gro on the device peer:
> >
> > https://github.com/torvalds/linux/blob/master/drivers/net/veth.c#L477
> >
> > we are just reflecting this behaviour in the xdp_features flag.
>
> Ok, I'm confused then why it passed before?
ack, you are right. I guess the issue is in veth driver code. In order to
enable NETDEV_XDP_ACT_NDO_XMIT for device "veth0", we need to check the peer
veth1 configuration since the check in veth_xdp_xmit() is on the peer rx queue.
Something like:
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index e1b38fbf1dd9..4b3c6647edc6 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1262,11 +1262,12 @@ static void veth_set_xdp_features(struct net_device *dev)
peer = rtnl_dereference(priv->peer);
if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
+ struct veth_priv *priv_peer = netdev_priv(peer);
xdp_features_t val = NETDEV_XDP_ACT_BASIC |
NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_RX_SG;
- if (priv->_xdp_prog || veth_gro_requested(dev))
+ if (priv_peer->_xdp_prog || veth_gro_requested(peer))
val |= NETDEV_XDP_ACT_NDO_XMIT |
NETDEV_XDP_ACT_NDO_XMIT_SG;
xdp_set_features_flag(dev, val);
@@ -1504,19 +1505,23 @@ static int veth_set_features(struct net_device *dev,
{
netdev_features_t changed = features ^ dev->features;
struct veth_priv *priv = netdev_priv(dev);
+ struct net_device *peer;
int err;
if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
return 0;
+ peer = rtnl_dereference(priv->peer);
if (features & NETIF_F_GRO) {
err = veth_napi_enable(dev);
if (err)
return err;
- xdp_features_set_redirect_target(dev, true);
+ if (peer)
+ xdp_features_set_redirect_target(peer, true);
} else {
- xdp_features_clear_redirect_target(dev);
+ if (peer)
+ xdp_features_clear_redirect_target(peer);
veth_napi_del(dev);
}
return 0;
@@ -1598,13 +1603,13 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
peer->max_mtu = max_mtu;
}
- xdp_features_set_redirect_target(dev, true);
+ xdp_features_set_redirect_target(peer, true);
}
if (old_prog) {
if (!prog) {
- if (!veth_gro_requested(dev))
- xdp_features_clear_redirect_target(dev);
+ if (peer && !veth_gro_requested(dev))
+ xdp_features_clear_redirect_target(peer);
if (dev->flags & IFF_UP)
veth_disable_xdp(dev);
What do you think?
Regards,
Lorenzo
>
> > > > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> > > > ---
> > > > tools/testing/selftests/bpf/prog_tests/xdp_bonding.c | 11 +++++++++++
> > > > 1 file changed, 11 insertions(+)
> > > >
> > > > diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> > > > index 5e3a26b15ec6..dcbe30c81291 100644
> > > > --- a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> > > > +++ b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
> > > > @@ -168,6 +168,17 @@ static int bonding_setup(struct skeletons *skeletons, int mode, int xmit_policy,
> > > > if (xdp_attach(skeletons, skeletons->xdp_dummy->progs.xdp_dummy_prog, "veth1_2"))
> > > > return -1;
> > > > +
> > > > + if (!ASSERT_OK(setns_by_name("ns_dst"), "set netns to ns_dst"))
> > > > + return -1;
> > > > +
> > > > + /* Load a dummy XDP program on veth2_2 in order to enable
> > > > + * NETDEV_XDP_ACT_NDO_XMIT feature
> > > > + */
> > > > + if (xdp_attach(skeletons, skeletons->xdp_dummy->progs.xdp_dummy_prog, "veth2_2"))
> > > > + return -1;
> > > > +
> > > > + restore_root_netns();
> > > > }
> > > > SYS("ip -netns ns_dst link set veth2_1 master bond2");
Attachment:
signature.asc
Description: PGP signature
