STRUCT VIRTQUEUE(9)

✨ struct virtqueue(9) ✨

okay bestie, welcome to the struct virtqueue(9) page, straight out of the Kernel API Manual 💅 this is literally the little data structure that says "hey, here's a queue, go register some buffers in it" — for sending or receiving, no cap 🎀

---

🌸 NAME 🌸

struct virtqueue — a queue to register buffers for sending or receiving. that's it, that's the whole vibe ✨

---

🦋 SYNOPSIS 🦋

here's the whole struct, character for character, don't touch a thing:

struct virtqueue {
    struct list_head list;
    void (*callback)(struct virtqueue *vq);
    const char *name;
    struct virtio_device *vdev;
    unsigned int index;
    unsigned int num_free;
    unsigned int num_max;
    bool reset;
    void *priv;
 };

---

👑 Members 👑

okay so let's meet the cast, each one gets a moment:

• list — the chain of virtqueues for this device. it's giving linked-list energy, one vq holding hands with the next 🫶
• callback — the function to call when buffers are consumed. and yes, it can be NULL — sometimes we just don't want the drama 💀
• name — the name of this virtqueue. mainly for debugging, so it's lowkey the vq's government name 👑
• vdev — the virtio device this queue was created for. every queue has a parent, iconic 🌈
• index — the zero-based ordinal number for this queue. zero-based, so the first one is 0, that's just how we do it 🍓
• num_free — number of elements we expect to be able to fit. like how many more snacks fit in the bag 🎀
• num_max — the maximum number of elements supported by the device. the absolute ceiling, the hard limit, periodt 🔥
• reset — vq is in reset state or not. it's a bool, so it's a yes-or-no baddie ⭐
• priv — a pointer for the virtqueue implementation to use. free real estate for whoever's implementing this thing 🙈

---

💖 Description 💖

the num_free note (important, pay attention bestie)

• with indirect buffers, each buffer needs one element in the queue. one buffer, one element. simple, clean, slay ✨
• otherwise, a buffer will need one element per sg element. so more sg elements = more elements needed, fr fr 💅

not me making you count queue elements 💀 but like, that's genuinely what it says in the source, so.

---

🔥 SEE ALSO 🔥

go read these next, iykyk:

• Kernel file ./include/linux/virtio.h
• struct virtio_device(9)
• struct virtio_driver(9)

---

and that's the whole page, bestie 🧚 this one came from ./include/linux — Copyright October 2026, struct virtqueue(9) — ok bye love u, go queue some buffers 💜