From 3d76a4d3d4e591af3e789698affaad88a5a8e8ab Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Thu, 19 Jan 2023 14:15:26 -0800 Subject: bpf: XDP metadata RX kfuncs Define a new kfunc set (xdp_metadata_kfunc_ids) which implements all possible XDP metatada kfuncs. Not all devices have to implement them. If kfunc is not supported by the target device, the default implementation is called instead. The verifier, at load time, replaces a call to the generic kfunc with a call to the per-device one. Per-device kfunc pointers are stored in separate struct xdp_metadata_ops. Cc: John Fastabend Cc: David Ahern Cc: Martin KaFai Lau Cc: Jakub Kicinski Cc: Willem de Bruijn Cc: Jesper Dangaard Brouer Cc: Anatoly Burakov Cc: Alexander Lobakin Cc: Magnus Karlsson Cc: Maryam Tahhan Cc: xdp-hints@xdp-project.net Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20230119221536.3349901-8-sdf@google.com Signed-off-by: Martin KaFai Lau --- kernel/bpf/offload.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'kernel/bpf/offload.c') diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c index f767455ed732..3e173c694bbb 100644 --- a/kernel/bpf/offload.c +++ b/kernel/bpf/offload.c @@ -755,6 +755,50 @@ void bpf_dev_bound_netdev_unregister(struct net_device *dev) up_write(&bpf_devs_lock); } +int bpf_dev_bound_kfunc_check(struct bpf_verifier_log *log, + struct bpf_prog_aux *prog_aux) +{ + if (!bpf_prog_is_dev_bound(prog_aux)) { + bpf_log(log, "metadata kfuncs require device-bound program\n"); + return -EINVAL; + } + + if (bpf_prog_is_offloaded(prog_aux)) { + bpf_log(log, "metadata kfuncs can't be offloaded\n"); + return -EINVAL; + } + + return 0; +} + +void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id) +{ + const struct xdp_metadata_ops *ops; + void *p = NULL; + + /* We don't hold bpf_devs_lock while resolving several + * kfuncs and can race with the unregister_netdevice(). + * We rely on bpf_dev_bound_match() check at attach + * to render this program unusable. + */ + down_read(&bpf_devs_lock); + if (!prog->aux->offload) + goto out; + + ops = prog->aux->offload->netdev->xdp_metadata_ops; + if (!ops) + goto out; + + if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP)) + p = ops->xmo_rx_timestamp; + else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_HASH)) + p = ops->xmo_rx_hash; +out: + up_read(&bpf_devs_lock); + + return p; +} + static int __init bpf_offload_init(void) { return rhashtable_init(&offdevs, &offdevs_params); -- cgit