libnvme(9)

💖 NAME 💖

struct libnvme_passthru_cmd — the nvme passthrough command structure, aka the little blueprint that lets you yeet a raw NVMe command straight through, bestie.

So this is libnvme we're talking about, and this page is literally just the one struct. Babygirl it is so important though — it's the whole "send whatever command I want" pipeline. 🔥

✨ SYNOPSIS ✨

Okay so here's the struct in all its glory, every single field, no skips:

struct libnvme_passthru_cmd {
    __u8 opcode;
    __u8 flags;
    __u16 rsvd1;
    __u32 nsid;
    __u32 cdw2;
    __u32 cdw3;
    __u64 metadata;
    __u64 addr;
    __u32 metadata_len;
    __u32 data_len;
    __u32 cdw10;
    __u32 cdw11;
    __u32 cdw12;
    __u32 cdw13;
    __u32 cdw14;
    __u32 cdw15;
    __u32 timeout_ms;
    __u32 rsvd2;
    __u64 result;
 };

She's giving "long list of dwords" and honestly? We respect her for it. 👑

🌸 Members 🌸

Breakdown time, one field at a time, no cap:

• opcode — the Operation code, bestie. Go look at enum libnvme_io_opcodes and enum libnvme_admin_opcodes for the full menu. 🍓
• flags — Supported only for NVMe-MI. That's it, that's the note. 🙈
• rsvd1 — Reserved for future use. Not your business (yet). 🎀
• nsid — the Namespace Identifier, or a Fabrics type. Depends on the vibe. 🦋
• cdw2 — Command Dword 2 (no spec defined use). It's just there, existing, main character energy of a placeholder. 💅
• cdw3 — Command Dword 3 (no spec defined use). Same situation, different dword. ✨
• metadata — User space address to the metadata buffer (NULL if not used, so please don't point it at nonsense). 🧚
• addr — User space address to the data buffer (NULL if not used). Same rules, same energy. ⭐
• metadata_len — Metadata buffer transfer length. How much metadata is actually travelling, fr fr. 📏
• data_len — Data buffer transfer length. How much data is actually travelling. 🌈
• cdw10 — Command Dword 10 (command specific). Meaning lives in the command, not here. 🔥
• cdw11 — Command Dword 11 (command specific). Same deal. 💜
• cdw12 — Command Dword 12 (command specific). Yep, again. 🫶
• cdw13 — Command Dword 13 (command specific). The pattern is patterning. 💀
• cdw14 — Command Dword 14 (command specific). Still going. 🌸
• cdw15 — Command Dword 15 (command specific). Last of the dword girlies, we love a finale. 👑
• timeout_ms — If non-zero, this overrides the system default timeout, in milliseconds. So if you set it, you are the timeout now. ⏰
• rsvd2 — Reserved for future use (and fills an implicit struct pad — yes the parenthesis is literally never closed in the source, iykyk, that's just how it shipped 💀). Still reserved though! 🙅‍♀️
• result — Set on completion to the command's CQE DWORD 0-1 controller response. This is where you find out what actually happened. 😭

Ngl, a good chunk of this struct is "command specific" and "reserved for future use", so if you're confused, that's not a skill issue — the spec is just like that. 🫶

🎀 a lil sign-off 🎀

That's the whole page, bestie — struct libnvme_passthru_cmd from the libnvme(9) API Manual, dated October 2026. Go forth and passthrough responsibly. Slay. 💅✨🦋