STRUCT ACRN_IOEVENTFD(9)

✨ struct acrn_ioeventfd(9) ✨

okay bestie, so this is a page from the Kernel API Manual and it's literally all about struct acrn_ioeventfd — the lil data bundle you use to operate a &struct hsm_ioeventfd. yes, the naming is a choice. we move. 💅

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🌸 NAME 🌸

struct acrn_ioeventfd — the data you need to operate a &struct hsm_ioeventfd 🎀

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🦋 SYNOPSIS 🦋

here's the whole shape of it, no cap:

struct acrn_ioeventfd {
    __u32 fd;
    __u32 flags;
    __u64 addr;
    __u32 len;
    __u32 reserved;
    __u64 data;
 };

look at her. iconic. ✨

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💖 Members 💖

every field, every vibe, iykyk:

• fd — the fd of the eventfd that's associated with a hsm_ioeventfd 🫶
• flags — a logical-OR of ACRN_IOEVENTFD_FLAG_* (yes, OR them together, it's giving build-a-bear)
• addr — the start address of the IO range of the ioeventfd 📍
• len — the length of that IO range of the ioeventfd
• reserved — reserved, and fr fr it should be 0 🚨
• data — data for data matching (that's the actual description, she's a little mysterious, we respect it) 💀

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🔥 Description 🔥

okay so here's the tea, and this part is genuinely important:

• Without the flag ACRN_IOEVENTFD_FLAG_DEASSIGN, the ioctl ACRN_IOCTL_IOEVENTFD creates a struct hsm_ioeventfd whose properties originate from struct acrn_ioeventfd. new struct, fresh out the box, slay. 🌈
• With the flag ACRN_IOEVENTFD_FLAG_DEASSIGN, that same ioctl ACRN_IOCTL_IOEVENTFD destroys the struct hsm_ioeventfd matching the fd. rip bestie, you had a good run. 😭

so like, one flag is the difference between "make it" and "unmake it" — do not mix those up, that's the whole plot. 💀

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👑 SEE ALSO 👑

• Kernel file ./include/uapi/linux/acrn.h
• struct acrn_mmio_request(9)
• struct acrn_pio_request(9)
• struct acrn_pci_request(9)
• struct acrn_io_request(9)
• struct acrn_ioreq_notify(9)
• struct acrn_vm_creation(9)
• struct acrn_gp_regs(9)
• struct acrn_descriptor_ptr(9)
• struct acrn_regs(9)
• struct acrn_vcpu_regs(9)
• struct acrn_vm_memmap(9)
• struct acrn_ptdev_irq(9)
• struct acrn_pcidev(9)
• struct acrn_mmio_dev_res(9)
• struct acrn_mmiodev(9)
• struct acrn_vdev(9)
• struct acrn_msi_entry(9)
• struct acrn_cstate_data(9)
• struct acrn_pstate_data(9)
• struct acrn_irqfd(9)

that's the whole friend group right there, go say hi 🧚

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and that's the page!! mwah 💜 this one lives in ./include/uapi/linux and the version/date tag on it says October 2026 — so yeah, bookmark her, she's from the future and she ate. periodt. 🎀✨