Merge branch 'xdp: hints via kfuncs'

Stanislav Fomichev says:

====================

Please see the first patch in the series for the overall
design and use-cases.

See the following email from Toke for the per-packet metadata overhead:
https://lore.kernel.org/bpf/20221206024554.3826186-1-sdf@google.com/T/#m49d48ea08d525ec88360c7d14c4d34fb0e45e798

Recent changes:
- Keep new functions in en/xdp.c, do 'extern mlx5_xdp_metadata_ops' (Tariq)

- Remove mxbuf pointer and use xsk_buff_to_mxbuf (Tariq)

- Clarify xdp_buff vs 'XDP frame' (Jesper)

- Explicitly mention that AF_XDP RX descriptor lacks metadata size (Jesper)

- Drop libbpf_flags/xdp_flags from selftests and use ifindex instead
  of ifname (due to recent xsk.h refactoring)

Prior art (to record pros/cons for different approaches):

- Stable UAPI approach:
  https://lore.kernel.org/bpf/20220628194812.1453059-1-alexandr.lobakin@intel.com/
- Metadata+BTF_ID appoach:
  https://lore.kernel.org/bpf/166256538687.1434226.15760041133601409770.stgit@firesoul/
- v7:
  https://lore.kernel.org/bpf/20230112003230.3779451-1-sdf@google.com/
- v6:
  https://lore.kernel.org/bpf/20230104215949.529093-1-sdf@google.com/
- v5:
  https://lore.kernel.org/bpf/20221220222043.3348718-1-sdf@google.com/
- v4:
  https://lore.kernel.org/bpf/20221213023605.737383-1-sdf@google.com/
- v3:
  https://lore.kernel.org/bpf/20221206024554.3826186-1-sdf@google.com/
- v2:
  https://lore.kernel.org/bpf/20221121182552.2152891-1-sdf@google.com/
- v1:
  https://lore.kernel.org/bpf/20221115030210.3159213-1-sdf@google.com/
- kfuncs v2 RFC:
  https://lore.kernel.org/bpf/20221027200019.4106375-1-sdf@google.com/
- kfuncs v1 RFC:
  https://lore.kernel.org/bpf/20221104032532.1615099-1-sdf@google.com/

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org

Stanislav Fomichev (13):
  bpf: Document XDP RX metadata
  bpf: Rename bpf_{prog,map}_is_dev_bound to is_offloaded
  bpf: Move offload initialization into late_initcall
  bpf: Reshuffle some parts of bpf/offload.c
  bpf: Introduce device-bound XDP programs
  selftests/bpf: Update expected test_offload.py messages
  bpf: XDP metadata RX kfuncs
  veth: Introduce veth_xdp_buff wrapper for xdp_buff
  veth: Support RX XDP metadata
  selftests/bpf: Verify xdp_metadata xdp->af_xdp path
  net/mlx4_en: Introduce wrapper for xdp_buff
  net/mlx4_en: Support RX XDP metadata
  selftests/bpf: Simple program to dump XDP RX metadata
====================

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 21 insertions, 13 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 35ffd808f281..d5ffa7a01dfb 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -181,7 +181,7 @@ static int bpf_map_update_value(struct bpf_map *map, struct file *map_file,
 	int err;
 
 	/* Need to create a kthread, thus must support schedule */
-	if (bpf_map_is_dev_bound(map)) {
+	if (bpf_map_is_offloaded(map)) {
 		return bpf_map_offload_update_elem(map, key, value, flags);
 	} else if (map->map_type == BPF_MAP_TYPE_CPUMAP ||
 		   map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
@@ -238,7 +238,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,
 	void *ptr;
 	int err;
 
-	if (bpf_map_is_dev_bound(map))
+	if (bpf_map_is_offloaded(map))
 		return bpf_map_offload_lookup_elem(map, key, value);
 
 	bpf_disable_instrumentation();
@@ -1483,7 +1483,7 @@ static int map_delete_elem(union bpf_attr *attr, bpfptr_t uattr)
 		goto err_put;
 	}
 
-	if (bpf_map_is_dev_bound(map)) {
+	if (bpf_map_is_offloaded(map)) {
 		err = bpf_map_offload_delete_elem(map, key);
 		goto out;
 	} else if (IS_FD_PROG_ARRAY(map) ||
@@ -1547,7 +1547,7 @@ static int map_get_next_key(union bpf_attr *attr)
 	if (!next_key)
 		goto free_key;
 
-	if (bpf_map_is_dev_bound(map)) {
+	if (bpf_map_is_offloaded(map)) {
 		err = bpf_map_offload_get_next_key(map, key, next_key);
 		goto out;
 	}
@@ -1605,7 +1605,7 @@ int generic_map_delete_batch(struct bpf_map *map,
 				   map->key_size))
 			break;
 
-		if (bpf_map_is_dev_bound(map)) {
+		if (bpf_map_is_offloaded(map)) {
 			err = bpf_map_offload_delete_elem(map, key);
 			break;
 		}
@@ -1851,7 +1851,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr)
 		   map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
 		   map->map_type == BPF_MAP_TYPE_LRU_HASH ||
 		   map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
-		if (!bpf_map_is_dev_bound(map)) {
+		if (!bpf_map_is_offloaded(map)) {
 			bpf_disable_instrumentation();
 			rcu_read_lock();
 			err = map->ops->map_lookup_and_delete_elem(map, key, value, attr->flags);
@@ -1944,7 +1944,7 @@ static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
 	if (!ops)
 		return -EINVAL;
 
-	if (!bpf_prog_is_dev_bound(prog->aux))
+	if (!bpf_prog_is_offloaded(prog->aux))
 		prog->aux->ops = ops;
 	else
 		prog->aux->ops = &bpf_offload_prog_ops;
@@ -2255,7 +2255,7 @@ bool bpf_prog_get_ok(struct bpf_prog *prog,
 
 	if (prog->type != *attach_type)
 		return false;
-	if (bpf_prog_is_dev_bound(prog->aux) && !attach_drv)
+	if (bpf_prog_is_offloaded(prog->aux) && !attach_drv)
 		return false;
 
 	return true;
@@ -2491,7 +2491,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 				 BPF_F_TEST_STATE_FREQ |
 				 BPF_F_SLEEPABLE |
 				 BPF_F_TEST_RND_HI32 |
-				 BPF_F_XDP_HAS_FRAGS))
+				 BPF_F_XDP_HAS_FRAGS |
+				 BPF_F_XDP_DEV_BOUND_ONLY))
 		return -EINVAL;
 
 	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
@@ -2575,7 +2576,7 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 	prog->aux->attach_btf = attach_btf;
 	prog->aux->attach_btf_id = attr->attach_btf_id;
 	prog->aux->dst_prog = dst_prog;
-	prog->aux->offload_requested = !!attr->prog_ifindex;
+	prog->aux->dev_bound = !!attr->prog_ifindex;
 	prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE;
 	prog->aux->xdp_has_frags = attr->prog_flags & BPF_F_XDP_HAS_FRAGS;
 
@@ -2599,7 +2600,14 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 	prog->gpl_compatible = is_gpl ? 1 : 0;
 
 	if (bpf_prog_is_dev_bound(prog->aux)) {
-		err = bpf_prog_offload_init(prog, attr);
+		err = bpf_prog_dev_bound_init(prog, attr);
+		if (err)
+			goto free_prog_sec;
+	}
+
+	if (type == BPF_PROG_TYPE_EXT && dst_prog &&
+	    bpf_prog_is_dev_bound(dst_prog->aux)) {
+		err = bpf_prog_dev_bound_inherit(prog, dst_prog);
 		if (err)
 			goto free_prog_sec;
 	}
@@ -3997,7 +4005,7 @@ static int bpf_prog_get_info_by_fd(struct file *file,
 			return -EFAULT;
 	}
 
-	if (bpf_prog_is_dev_bound(prog->aux)) {
+	if (bpf_prog_is_offloaded(prog->aux)) {
 		err = bpf_prog_offload_info_fill(&info, prog);
 		if (err)
 			return err;
@@ -4225,7 +4233,7 @@ static int bpf_map_get_info_by_fd(struct file *file,
 	}
 	info.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;
 
-	if (bpf_map_is_dev_bound(map)) {
+	if (bpf_map_is_offloaded(map)) {
 		err = bpf_map_offload_info_fill(&info, map);
 		if (err)
 			return err;