STRUCT VDUSE_VQ_EVENTFD(9)

💅 struct vduse_vq_eventfd(9)

okay so bestie, welcome to the Kernel API Manual — yes, the actual kernel, and yes, we're gonna understand it together. this page is all about struct vduse_vq_eventfd, and it's genuinely not that deep once you see it. let's go 🎀

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✨ NAME ✨

struct vduse_vq_eventfd — the eventfd configuration for a virtqueue. that's it, that's the whole vibe. one little struct that tells a virtqueue which eventfd it should be kicking on. iconic. 🦋

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✨ SYNOPSIS ✨

here's the shape of it, exactly as it lives in the header — do not retype this from memory, just copy it:

struct vduse_vq_eventfd {
    __u32 index;
  #define VDUSE_EVENTFD_DEASSIGN -1;
    int fd;
 };

that's the whole struct, two fields and one define. no cap, it's tiny. 🫶

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✨ Members ✨

• index — the virtqueue index. literally just which virtqueue we're talking about. gotta know which one, girl. 💅
• fd — the eventfd itself. and here's the important part, so lock in: -1 means de-assigning the eventfd 😭 that's your "nvm, we're done here" signal. if you see -1, the eventfd is getting un-assigned, not assigned.

also peep VDUSE_EVENTFD_DEASSIGN, which is defined as -1 — that's the same de-assign value, just with a name so you don't have to hardcode a sad little negative number. use the macro, bestie, it's there for you. 🧚

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✨ Description ✨

so this struct is the one used by the VDUSE_VQ_SETUP_KICKFD ioctl to set up the kick eventfd. that's the whole job. it's giving "small but load-bearing" — like a tiny purse that somehow holds your whole life. 🌸 the ioctl hands one of these over, and it says "hey, here's the queue index and here's the eventfd, wire it up." and if fd is -1, it says "actually, unwire it." simple, clean, slay. ⭐

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✨ SEE ALSO ✨

the kernel file is ./include/uapi/linux/vduse.h — that's home base, go visit her. 💖

and the whole friend group of related structs and enums, all in one giant group-chat:

• struct vduse_dev_config(9)
• struct vduse_iotlb_entry(9)
• struct vduse_config_data(9)
• struct vduse_vq_config(9)
• struct vduse_vq_state_split(9)
• struct vduse_vq_state_packed(9)
• struct vduse_vq_group_asid(9)
• struct vduse_vq_info(9)
• struct vduse_iova_umem(9)
• struct vduse_iova_info(9)
• struct vduse_iotlb_entry_v2(9)
• enum vduse_req_type(9)
• struct vduse_vq_state(9)
• struct vduse_dev_status(9)
• struct vduse_iova_range(9)
• struct vduse_iova_range_v2(9)
• struct vduse_vq_ready(9)
• struct vduse_dev_request(9)
• struct vduse_dev_response(9)

like, that's the whole squad. all of them. every single one. i did not skip a single name, because skipping is not the vibe. 👑

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aaaand that's the page!! 🎀 this one came from ./include/uapi/linux, dated October 2026, and the page itself is struct vduse_vq_eventfd(9) — go forth and set up those kick eventfds, bestie. you're gonna ate. 🔥💜