On Mon, Aug 19, 2024 at 6:53 PM Jakub Kicinski kuba@kernel.org wrote:
On Mon, 19 Aug 2024 00:44:27 +0900 Taehee Yoo wrote:
@@ -9537,6 +9540,10 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time"); return -EEXIST; }
if (dev_get_max_mp_channel(dev) != -1) {NL_SET_ERR_MSG(extack, "XDP can't be installed on a netdev using memory providers");return -EINVAL;}Should we consider virtual interfaces like bonding, bridge, etc? Virtual interfaces as an upper interface of physical interfaces can still install XDP prog.
# ip link add bond0 type bond # ip link set eth0 master bond0 # ip link set bond0 xdp pin /sys/fs/bpf/x/y and # ip link set bond0 xdpgeneric pin /sys/fs/bpf/x/y
All virtual interfaces can install generic XDP prog. The bonding interface can install native XDP prog.
Good point. We may need some common helpers to place the checks for XDP. They are spread all over the place now.
Took a bit of a look here. Forgive me, I'm not that familiar with XDP and virtual interfaces, so I'm a bit unsure what to do here.
For veth, it seems, the device behind the veth is stored in veth_priv->peer, so it seems maybe a dev_get_max_mp_channel() check on veth_priv->peer is the way to go to disable this for veth? I think we need to do this check on creation of the veth and on the ndo_bpf of veth.
For bonding, it seems we need to add mp channel check in bond_xdp_set, and bond_enslave?
There are a few other drivers that define ndo_add_slave, seems a check in br_add_slave is needed as well.
This seems like a potentially deep rabbit hole with a few checks to add all of the place. Is this blocking the series? AFAICT if XDP fails with mp-bound queues with a benign error, that seems fine to me; I don't have a use case for memory providers + xdp yet. This should only be blocking if someone can repro a very serious error (kernel crash) or something with this combination.
I can try to add these checks locally and propose as a follow up series. Let me know if I'm on the right track with figuring out how to implement this, and, if you feel like it's blocking.