STRUCT NFP_INSN_META(9)

💅 struct nfp_insn_meta(9) — BPF instruction wrapper

okay so bestie, welcome to the Kernel API Manual entry for struct nfp_insn_meta, aka the little glow-up wrapper that holds one BPF instruction and all its side quests. this thing is literally the main character of the NFP BPF JIT. let's get into it 🎀

---

✨ SYNOPSIS ✨

struct nfp_insn_meta {
    struct bpf_insn insn;
    union {
      struct {
        struct bpf_reg_state ptr;
        struct bpf_insn *paired_st;
        s16 ldst_gather_len;
        bool ptr_not_const;
        struct {
          s16 range_start;
          s16 range_end;
          bool do_init;
        } pkt_cache;
        bool xadd_over_16bit;
        bool xadd_maybe_16bit;
      };
      struct {
        struct nfp_insn_meta *jmp_dst;
        bool jump_neg_op;
        u32 num_insns_after_br;
      };
      struct {
        u32 func_id;
        struct bpf_reg_state arg1;
        struct nfp_bpf_reg_state arg2;
      };
      struct {
        u64 umin_src;
        u64 umax_src;
        u64 umin_dst;
        u64 umax_dst;
      };
    };
    unsigned int off;
    unsigned short n;
    unsigned short flags;
    unsigned short subprog_idx;
    instr_cb_t double_cb;
    struct list_head l;
 };

no cap, that's the whole shape of it. the big anonymous union in the middle means only one of those little structs is live at a time — it's giving "one outfit per occasion" energy. 🦋

---

🌸 Members 🌸

the basics

• insn — the BPF instruction itself. the whole reason we're here fr fr.

{unnamed_union}

anonymous. she has no name and she doesn't need one 💅

{unnamed_struct} (the memory-ops one)

anonymous — this is the cluster for memory operations.

• ptr — pointer type for memory operations
• paired_st — the paired store insn at the head of the sequence
• ldst_gather_len — memcpy length gathered from load/store sequence
• ptr_not_const — pointer is not always constant
• pkt_cache — packet data cache information
  • pkt_cache.range_start — start offset for associated packet data cache
  • pkt_cache.range_end — end offset for associated packet data cache
  • pkt_cache.do_init — this read needs to initialize packet data cache
• xadd_over_16bit — 16bit immediate is not guaranteed
• xadd_maybe_16bit — 16bit immediate is possible

{unnamed_struct} (the jump one)

anonymous — jump instructions get their own little corner 🐇

• jmp_dst — destination info for jump instructions
• jump_neg_op — jump instruction has inverted immediate, use ADD instead of SUB
• num_insns_after_br — number of insns following a branch jump, used for fixup

{unnamed_struct} (the call one)

anonymous — call instructions, bestie 📞

• func_id — function id for call instructions
• arg1 — arg1 for call instructions
• arg2 — arg2 for call instructions

{unnamed_struct} (the verifier-range one)

anonymous — the min/max bookkeeping squad.

• umin_src — copy of core verifier umin_value for src opearnd. (yes the source really spells it "opearnd", we keep it verbatim, she's iconic 💀)
• umax_src — copy of core verifier umax_value for src operand.
• umin_dst — copy of core verifier umin_value for dst opearnd.
• umax_dst — copy of core verifier umax_value for dst operand.

the rest of the squad

• off — index of first generated machine instruction (in nfp_prog.prog)
• n — eBPF instruction number
• flags — eBPF instruction extra optimization flags
• subprog_idx — index of subprogram to which the instruction belongs
• double_cb — callback for second part of the instruction
• l — link on nfp_prog->insns list

not me pointing out that double_cb is literally a callback for the second part of the instruction — two-part release, we love a deluxe edition 🔥

---

🌈 SEE ALSO 🌈

• Kernel file ./drivers/net/ethernet/netronome/nfp/bpf/main.h struct nfp_app_bpf(9), struct nfp_bpf_map(9), struct nfp_bpf_reg_state(9), struct nfp_bpf_subprog_info(9), struct nfp_prog(9), struct nfp_bpf_vnic(9)

go read those too, they're all in the same friend group 🫶

---

later bestie 💖 this page came from ./drivers/net/ethernet/netrono... and it's dated October 2026 — so it's serving future-flavoured AND kernel-flavoured at the same time. obsessed. ⭐👑