_vdpa_register_device(9)

💅 _vdpa_register_device(9)

okay so this is a page straight outta the Kernel API Manual, and it's about registering a vDPA device — with the vdpa lock already held, bestie. read that again. held. this is the underscore version, the lowkey internal one, so the locking is on you. 🫶

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✨ NAME ✨

_vdpa_register_device — register a vDPA device with the vdpa lock held, no cap 💅

okay so the receipts first, because this is the part people skip and then cry about:

• the caller must have a successful call of vdpa_alloc_device() before this. like, a succeed call. no device allocated = nothing to register, periodt. 😭
• the caller must invoke this routine inside the management device's dev_add() callback — and after setting up a valid mgmtdev for this vdpa device. both. in that order. the vibe check here is: right place, right setup, then register. 🌸

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🦋 SYNOPSIS 🦋

int _vdpa_register_device (struct vdpa_device *vdev , u32 nvqs );

yes it returns an int, yes it takes exactly two things, and yes the spacing in the manpage is a little quirky — we don't fix what isn't broken. 🎀

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🌈 ARGUMENTS 🌈

• vdev — the struct vdpa_device * that's getting registered onto the vDPA bus. this is your device, the main character of this whole operation 👑
• nvqs — a u32, the number of virtqueues this device supports. literally how many queues your device brings to the party. count them. accurately. 🔥

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⭐ RETURN ⭐

Returns an error when it fails to add the device to the vDPA bus. that's the whole deal — no error means slay, an error means the bus said no and you gotta deal with it. 💀

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🧚 SEE ALSO 🧚

the whole friend group, and yes you should meet all of them:

• Kernel file ./drivers/vdpa/vdpa.c
• __vdpa_alloc_device(9)
• vdpa_register_device(9)
• _vdpa_unregister_device(9)
• vdpa_unregister_device(9)
• __vdpa_register_driver(9)
• vdpa_unregister_driver(9)
• vdpa_mgmtdev_register(9)
• vdpa_get_config(9)
• vdpa_set_config(9)

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ngl the two things to remember forever: lock held, and called from dev_add() after the mgmtdev is valid. everything else is vibes. 🍓

that's the page!! mwah 💖 — this one lives in ./drivers/vdpa, dated October 2026, in the Kernel API Manual (seriously, that's the manual name, we're not being cute, well — we are being cute, but it's also true). go register something responsibly, bestie 💜🌷