iommu_unmap(9)

📦 version 7.3.1, in nixpkgs unstable

💅 iommu_unmap — bestie's guide to tearing down IOVA mappings 💅

okay so this page is from the Kernel API Manual (yes, the iommu_unmap(9) one, the icon herself ✨). Sit down, grab a strawberry drink 🍓, and let's get into it.

✨ NAME ✨

iommu_unmap — literally removes mappings from a range of IOVA. that's it, that's the vibe 🌸

🦋 SYNOPSIS 🦋

size_t iommu_unmap (struct iommu_domain *domain , unsigned long iova ,
       size_t size );

look at her. three arguments, returns a size_t, no notes 💅

🎀 ARGUMENTS 🎀

  • domain — the domain you're manipulating. your little playground 🫶
  • iova — the IO virtual address where you're starting. the starting line, the main character's entrance ✨
  • size — the length of the range, counting from iova. how far the vibe extends 💜

🔥 DESCRIPTION 🔥

so iommu_unmap will remove a translation that was created by iommu_map. like, undoing what the other girl did 🙈. it's giving cleanup era.

IMPORTANT bestie: it cannot subdivide a mapping created by iommu_map. so like, you gotta call it with IOVA ranges that match what was passed to iommu_map — no cap, no splitting, no "close enough" energy 💀.

the range can aggregate contiguous iommu_map calls though — so long as no individual range is split. so you CAN group them, you just can't slice one in half. periodt. 👑

⭐ RETURN ⭐

returns the number of bytes of IOVA unmapped. and heads up: iova + res will be the point where unmapping stopped. that's how you know where she got to before she clocked out 💅

🌈 SEE ALSO 🌈

Kernel file ./drivers/iommu/iommu.c — and honestly the whole group chat showed up, so here they all are, every single one, iykyk:

and that's the page, bestie 🧚💖 keep it in this directory: ./drivers/iommu, dated October 2026, and go unmap something responsibly. slay 🎀✨

📦 where this page comes from