libnvme(2)

💖 libnvme — the struct nvme_mi_read_ctrl_info era 💖

okay bestie, so this is a page from the libnvme API Manual (yes, libnvme(2), that's the manual name, we're fancy like that ✨), and today's main character is a lil struct that carries Controller Information Data Structure energy. sit down, hydrate, let's go 🫶

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✨ NAME ✨

struct nvme_mi_read_ctrl_info — the Controller Information Data Structure. it's giving "here's everything you need to know about this controller, no cap" 💅

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🌸 SYNOPSIS 🌸

struct nvme_mi_read_ctrl_info {
    __u8 portid;
    __u8 rsvd1[4];
    __u8 prii;
    __le16 pri;
    __le16 vid;
    __le16 did;
    __le16 ssvid;
    __le16 ssid;
    __u8 rsvd16[16];
 };

look at her. iconic. not a single byte out of place 😌 note that all the multibyte fields are __le16 — little-endian, always, don't play with endianness, that's not the vibe 🔥

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🎀 Members 🎀

okay this is the part where we go field by field, and trust, you're gonna want to know all of them 👑

• portid — Port Identifier. literally the port's id. that's it, that's the job 💫
• rsvd1 — Reserved. do NOT touch. it's just sitting there, minding its business, holding space (4 bytes of space, to be exact) 🙈
• prii — PCIe Routing ID Information. the info about the routing id. the little pre-game before the actual routing id shows up 🦋
• pri — PCIe Routing ID. the routing id itself, in all its __le16 glory ✨
• vid — PCI Vendor ID. who made this thing 👑
• did — PCI Device ID. which thing is this thing 👑
• ssvid — PCI Subsystem Vendor ID. the vendor of the subsystem, not the vendor of the device. yes they can be different. yes that's on purpose 💅
• ssid — PCI Subsystem Device ID. the device id of the subsystem. the matching half of the ssvid situation 💖
• rsvd16 — Reserved. again. 16 whole bytes of reserved. not me spiralling over how much reserved space this struct is holding 😭 it's fine. it's fine. leave it ALONE 🌸

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⚠️ quick ✨vibe check✨ for the reserved fields: rsvd1 and rsvd16 are Reserved, meaning you do not read meaning into them and you do not write your own little secrets in there. hands off, bestie 🫶

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💜 the sign-off 💜

and that's the page, fr fr 🌈 this one came from the libnvm source/version, dated July 2026, and it answers to the name struct nvme_mi_read_ctrl_info under the libnvme(2) manual 🎀

go forth and read your controller info correctly, you absolute legend 👑💖