libnvme(9)

💖 libnvme(9) — the API Manual, bestie edition 💖

Okay so real quick before we dive in: this is a page from libnvme, the API manual, section 9. It's short, it's sweet, and it's literally just one struct. Let's go 🫶

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✨ NAME ✨

struct nvme_feat_host_behavior — Host Behavior Support, as a Data Structure. That's the whole vibe. It's the struct that holds all your host-behavior-feature bits in one cute little bundle 🎀

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🌸 SYNOPSIS 🌸

Here's the shape of it, exactly as it lives in the header — no cap, copy it character for character:

struct nvme_feat_host_behavior {
    __u8 acre;
    __u8 etdas;
    __u8 lbafee;
    __u8 hdisns;
    __le16 cdfe;
    __u8 rsvd6[506];
 };

So yeah — four single bytes, then a little-endian 16-bit field, then a big ol' 506-byte reserved chunk living its best life at the end 🦋

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👑 Members 👑

Let's do a little meet-and-greet with every single field, because everyone gets their moment:

• acre — Advanced Command Retry Enable 🔥
• etdas — Extended Telemetry Data Area 4 Supported 📊
• lbafee — LBA Format Extension Enable 💅
• hdisns — Host Dispersed Namespace Support 🌈
• cdfe — Copy Descriptor Formats Enable 📋
• rsvd6 — Reserved 🙈 (it's reserved, bestie, don't touch it, it's not doing anything and that's its whole job)

Side note, and I mean this with love: rsvd6 is 506 bytes because that offset math has to land right. Never repurpose reserved fields, that's how you end up in a group chat with the kernel maintainers 💀

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Okay that's genuinely the whole page — short king behavior, honestly. This was struct nvme_feat_host_behavior from the libnvme(9) API Manual, dated October 2026. Slay, go populate your host behavior feature bits, and drink some water 💜✨