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Date: Thu, 22 Apr 2021 17:26:39 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: davem@...emloft.net
Cc: daniel@...earbox.net, andrii@...nel.org, netdev@...r.kernel.org,
bpf@...r.kernel.org, kernel-team@...com
Subject: [PATCH v2 bpf-next 09/16] libbpf: Support for fd_idx
From: Alexei Starovoitov <ast@...nel.org>
Add support for FD_IDX make libbpf prefer that approach to loading programs.
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
tools/lib/bpf/bpf.c | 1 +
tools/lib/bpf/libbpf.c | 70 +++++++++++++++++++++++++++++----
tools/lib/bpf/libbpf_internal.h | 1 +
3 files changed, 65 insertions(+), 7 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index bba48ff4c5c0..b96a3aba6fcc 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -252,6 +252,7 @@ int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr)
attr.prog_btf_fd = load_attr->prog_btf_fd;
attr.prog_flags = load_attr->prog_flags;
+ attr.fd_array = ptr_to_u64(load_attr->fd_array);
attr.func_info_rec_size = load_attr->func_info_rec_size;
attr.func_info_cnt = load_attr->func_info_cnt;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 254a0c9aa6cf..17cfc5b66111 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -176,6 +176,8 @@ enum kern_feature_id {
FEAT_MODULE_BTF,
/* BTF_KIND_FLOAT support */
FEAT_BTF_FLOAT,
+ /* Kernel support for FD_IDX */
+ FEAT_FD_IDX,
__FEAT_CNT,
};
@@ -288,6 +290,7 @@ struct bpf_program {
__u32 line_info_rec_size;
__u32 line_info_cnt;
__u32 prog_flags;
+ int *fd_array;
};
struct bpf_struct_ops {
@@ -4181,6 +4184,24 @@ static int probe_module_btf(void)
return !err;
}
+static int probe_kern_fd_idx(void)
+{
+ struct bpf_load_program_attr attr;
+ struct bpf_insn insns[] = {
+ BPF_LD_IMM64_RAW(BPF_REG_0, BPF_PSEUDO_MAP_IDX, 0),
+ BPF_EXIT_INSN(),
+ };
+
+ memset(&attr, 0, sizeof(attr));
+ attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
+ attr.insns = insns;
+ attr.insns_cnt = ARRAY_SIZE(insns);
+ attr.license = "GPL";
+
+ probe_fd(bpf_load_program_xattr(&attr, NULL, 0));
+ return errno == EPROTO;
+}
+
enum kern_feature_result {
FEAT_UNKNOWN = 0,
FEAT_SUPPORTED = 1,
@@ -4231,6 +4252,9 @@ static struct kern_feature_desc {
[FEAT_BTF_FLOAT] = {
"BTF_KIND_FLOAT support", probe_kern_btf_float,
},
+ [FEAT_FD_IDX] = {
+ "prog_load with fd_idx", probe_kern_fd_idx,
+ },
};
static bool kernel_supports(enum kern_feature_id feat_id)
@@ -6309,19 +6333,34 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
switch (relo->type) {
case RELO_LD64:
- insn[0].src_reg = BPF_PSEUDO_MAP_FD;
- insn[0].imm = obj->maps[relo->map_idx].fd;
+ if (kernel_supports(FEAT_FD_IDX)) {
+ insn[0].src_reg = BPF_PSEUDO_MAP_IDX;
+ insn[0].imm = relo->map_idx;
+ } else {
+ insn[0].src_reg = BPF_PSEUDO_MAP_FD;
+ insn[0].imm = obj->maps[relo->map_idx].fd;
+ }
break;
case RELO_DATA:
- insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
insn[1].imm = insn[0].imm + relo->sym_off;
- insn[0].imm = obj->maps[relo->map_idx].fd;
+ if (kernel_supports(FEAT_FD_IDX)) {
+ insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
+ insn[0].imm = relo->map_idx;
+ } else {
+ insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
+ insn[0].imm = obj->maps[relo->map_idx].fd;
+ }
break;
case RELO_EXTERN_VAR:
ext = &obj->externs[relo->sym_off];
if (ext->type == EXT_KCFG) {
- insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
- insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
+ if (kernel_supports(FEAT_FD_IDX)) {
+ insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
+ insn[0].imm = obj->kconfig_map_idx;
+ } else {
+ insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
+ insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
+ }
insn[1].imm = ext->kcfg.data_off;
} else /* EXT_KSYM */ {
if (ext->ksym.type_id) { /* typed ksyms */
@@ -7047,6 +7086,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.attach_btf_id = prog->attach_btf_id;
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
+ load_attr.fd_array = prog->fd_array;
/* specify func_info/line_info only if kernel supports them */
btf_fd = bpf_object__btf_fd(prog->obj);
@@ -7239,6 +7279,8 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
struct bpf_program *prog;
size_t i;
int err;
+ struct bpf_map *map;
+ int *fd_array = NULL;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
@@ -7247,6 +7289,16 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
return err;
}
+ if (kernel_supports(FEAT_FD_IDX) && obj->nr_maps) {
+ fd_array = malloc(sizeof(int) * obj->nr_maps);
+ if (!fd_array)
+ return -ENOMEM;
+ for (i = 0; i < obj->nr_maps; i++) {
+ map = &obj->maps[i];
+ fd_array[i] = map->fd;
+ }
+ }
+
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (prog_is_subprog(obj, prog))
@@ -7256,10 +7308,14 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
continue;
}
prog->log_level |= log_level;
+ prog->fd_array = fd_array;
err = bpf_program__load(prog, obj->license, obj->kern_version);
- if (err)
+ if (err) {
+ free(fd_array);
return err;
+ }
}
+ free(fd_array);
return 0;
}
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 6017902c687e..9114c7085f2a 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -204,6 +204,7 @@ struct bpf_prog_load_params {
__u32 log_level;
char *log_buf;
size_t log_buf_sz;
+ int *fd_array;
};
int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr);
--
2.30.2
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