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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
Merge branch 'bpf-allow-xdp_redirect-for-xdp-dev-bound-programs'
Lorenzo Bianconi says:
====================
bpf: Allow XDP_REDIRECT for XDP dev-bound programs
In the current implementation if the program is dev-bound to a specific
device, it will not be possible to perform XDP_REDIRECT into a DEVMAP or
CPUMAP even if the program is running in the driver NAPI context.
Fix the issue introducing __bpf_prog_map_compatible utility routine in
order to avoid bpf_prog_is_dev_bound() during the XDP program load.
Continue forbidding to attach a dev-bound program to XDP maps.
====================
Link: https://patch.msgid.link/20250428-xdp-prog-bound-fix-v3-0-c9e9ba3300c7@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
+50
-12
+16
-11
kernel/bpf/core.c
+16
-11
kernel/bpf/core.c
···
2358
2358
return 0;
2359
2359
}
2360
2360
2361
-
bool bpf_prog_map_compatible(struct bpf_map *map,
2362
-
const struct bpf_prog *fp)
2361
+
static bool __bpf_prog_map_compatible(struct bpf_map *map,
2362
+
const struct bpf_prog *fp)
2363
2363
{
2364
2364
enum bpf_prog_type prog_type = resolve_prog_type(fp);
2365
2365
bool ret;
2366
2366
struct bpf_prog_aux *aux = fp->aux;
2367
2367
2368
2368
if (fp->kprobe_override)
2369
-
return false;
2370
-
2371
-
/* XDP programs inserted into maps are not guaranteed to run on
2372
-
* a particular netdev (and can run outside driver context entirely
2373
-
* in the case of devmap and cpumap). Until device checks
2374
-
* are implemented, prohibit adding dev-bound programs to program maps.
2375
-
*/
2376
-
if (bpf_prog_is_dev_bound(aux))
2377
2369
return false;
2378
2370
2379
2371
spin_lock(&map->owner.lock);
···
2401
2409
return ret;
2402
2410
}
2403
2411
2412
+
bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp)
2413
+
{
2414
+
/* XDP programs inserted into maps are not guaranteed to run on
2415
+
* a particular netdev (and can run outside driver context entirely
2416
+
* in the case of devmap and cpumap). Until device checks
2417
+
* are implemented, prohibit adding dev-bound programs to program maps.
2418
+
*/
2419
+
if (bpf_prog_is_dev_bound(fp->aux))
2420
+
return false;
2421
+
2422
+
return __bpf_prog_map_compatible(map, fp);
2423
+
}
2424
+
2404
2425
static int bpf_check_tail_call(const struct bpf_prog *fp)
2405
2426
{
2406
2427
struct bpf_prog_aux *aux = fp->aux;
···
2426
2421
if (!map_type_contains_progs(map))
2427
2422
continue;
2428
2423
2429
-
if (!bpf_prog_map_compatible(map, fp)) {
2424
+
if (!__bpf_prog_map_compatible(map, fp)) {
2430
2425
ret = -EINVAL;
2431
2426
goto out;
2432
2427
}
+21
-1
tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+21
-1
tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
···
351
351
struct xdp_metadata2 *bpf_obj2 = NULL;
352
352
struct xdp_metadata *bpf_obj = NULL;
353
353
struct bpf_program *new_prog, *prog;
354
+
struct bpf_devmap_val devmap_e = {};
355
+
struct bpf_map *prog_arr, *devmap;
354
356
struct nstoken *tok = NULL;
355
357
__u32 queue_id = QUEUE_ID;
356
-
struct bpf_map *prog_arr;
357
358
struct xsk tx_xsk = {};
358
359
struct xsk rx_xsk = {};
359
360
__u32 val, key = 0;
···
410
409
bpf_program__set_ifindex(prog, rx_ifindex);
411
410
bpf_program__set_flags(prog, BPF_F_XDP_DEV_BOUND_ONLY);
412
411
412
+
/* Make sure we can load a dev-bound program that performs
413
+
* XDP_REDIRECT into a devmap.
414
+
*/
415
+
new_prog = bpf_object__find_program_by_name(bpf_obj->obj, "redirect");
416
+
bpf_program__set_ifindex(new_prog, rx_ifindex);
417
+
bpf_program__set_flags(new_prog, BPF_F_XDP_DEV_BOUND_ONLY);
418
+
413
419
if (!ASSERT_OK(xdp_metadata__load(bpf_obj), "load skeleton"))
414
420
goto out;
415
421
···
429
421
if (!ASSERT_ERR(bpf_map__update_elem(prog_arr, &key, sizeof(key),
430
422
&val, sizeof(val), BPF_ANY),
431
423
"update prog_arr"))
424
+
goto out;
425
+
426
+
/* Make sure we can't add dev-bound programs to devmaps. */
427
+
devmap = bpf_object__find_map_by_name(bpf_obj->obj, "dev_map");
428
+
if (!ASSERT_OK_PTR(devmap, "no dev_map found"))
429
+
goto out;
430
+
431
+
devmap_e.bpf_prog.fd = val;
432
+
if (!ASSERT_ERR(bpf_map__update_elem(devmap, &key, sizeof(key),
433
+
&devmap_e, sizeof(devmap_e),
434
+
BPF_ANY),
435
+
"update dev_map"))
432
436
goto out;
433
437
434
438
/* Attach BPF program to RX interface. */
+13
tools/testing/selftests/bpf/progs/xdp_metadata.c
+13
tools/testing/selftests/bpf/progs/xdp_metadata.c
···
19
19
__type(value, __u32);
20
20
} prog_arr SEC(".maps");
21
21
22
+
struct {
23
+
__uint(type, BPF_MAP_TYPE_DEVMAP);
24
+
__uint(key_size, sizeof(__u32));
25
+
__uint(value_size, sizeof(struct bpf_devmap_val));
26
+
__uint(max_entries, 1);
27
+
} dev_map SEC(".maps");
28
+
22
29
extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx,
23
30
__u64 *timestamp) __ksym;
24
31
extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
···
100
93
&meta->rx_vlan_tci);
101
94
102
95
return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
96
+
}
97
+
98
+
SEC("xdp")
99
+
int redirect(struct xdp_md *ctx)
100
+
{
101
+
return bpf_redirect_map(&dev_map, ctx->rx_queue_index, XDP_PASS);
103
102
}
104
103
105
104
char _license[] SEC("license") = "GPL";