libnvme(9)

💅 libnvme(9) 💅

okay so bestie, welcome to the libnvme(9) corner of the API manual — yes, the manual name is literally libnvme(9), it's giving iconic, it's giving "I live here now" ✨

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🌸 NAME 🌸

enum nvme_cmbsz — this field indicates the controller memory buffer size 🎀

like. the whole enum is about one field. one. and it's the controller memory buffer size. main character field energy fr fr.

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🦋 SYNOPSIS 🦋

enum nvme_cmbsz {
    NVME_CMBSZ_SQS_SHIFT ,
    NVME_CMBSZ_CQS_SHIFT ,
    NVME_CMBSZ_LISTS_SHIFT ,
    NVME_CMBSZ_RDS_SHIFT ,
    NVME_CMBSZ_WDS_SHIFT ,
    NVME_CMBSZ_SZU_SHIFT ,
    NVME_CMBSZ_SZ_SHIFT ,
    NVME_CMBSZ_SQS_MASK ,
    NVME_CMBSZ_CQS_MASK ,
    NVME_CMBSZ_LISTS_MASK ,
    NVME_CMBSZ_RDS_MASK ,
    NVME_CMBSZ_WDS_MASK ,
    NVME_CMBSZ_SZU_MASK ,
    NVME_CMBSZ_SZ_MASK ,
    NVME_CMBSZ_SZU_4K ,
    NVME_CMBSZ_SZU_64K ,
    NVME_CMBSZ_SZU_1M ,
    NVME_CMBSZ_SZU_16M ,
    NVME_CMBSZ_SZU_256M ,
    NVME_CMBSZ_SZU_4G ,
    NVME_CMBSZ_SZU_64G

};

copy it exactly, don't be out here renaming things, I'm watching 👀

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💖 Constants 💖

bestie we have THREE whole flavours of constant here and I need you to know each one. shifts, masks, and the size-unit values. periodt.

🧚 the shift amounts

• NVME_CMBSZ_SQS_SHIFT — shift amount to get the submission queue support. yes queen, just a shift amount 💅
• NVME_CMBSZ_CQS_SHIFT — shift amount to get the completion queue support
• NVME_CMBSZ_LISTS_SHIFT — shift amount to get the PLP SGL list support
• NVME_CMBSZ_RDS_SHIFT — shift amount to get the read data support
• NVME_CMBSZ_WDS_SHIFT — shift amount to get the write data support
• NVME_CMBSZ_SZU_SHIFT — shift amount to get the size units
• NVME_CMBSZ_SZ_SHIFT — shift amount to get the size

🌈 the masks

• NVME_CMBSZ_SQS_MASK — mask to get the submission queue support
• NVME_CMBSZ_CQS_MASK — mask to get the completion queue support
• NVME_CMBSZ_LISTS_MASK — mask to get the PLP SGL list support
• NVME_CMBSZ_RDS_MASK — mask to get the read data support
• NVME_CMBSZ_WDS_MASK — mask to get the write data support
• NVME_CMBSZ_SZU_MASK — mask to get the size units
• NVME_CMBSZ_SZ_MASK — mask to get the size

🍓 the size units (the SZU era, we love her)

• NVME_CMBSZ_SZU_4K — 4 KiB
• NVME_CMBSZ_SZU_64K — 64 KiB
• NVME_CMBSZ_SZU_1M — 1 MiB
• NVME_CMBSZ_SZU_16M — 16 MiB
• NVME_CMBSZ_SZU_256M — 256 MiB
• NVME_CMBSZ_SZU_4G — 4 GiB
• NVME_CMBSZ_SZU_64G — 64 GiB

lowkey a vibe check: these are the constants exactly as documented. no extra lore, no invented behaviour, I would never 🙈

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okay that's the whole page, you ate that 🫶 the source/version line is enum nvme_cmbsz from libnvme(9), and the date stamp says October 2026 — so go forth, shift those bits, mask those fields, and remember: 64 GiB of controller memory buffer is not a phase, it's a lifestyle 💜✨🎀