ENUM IOMMUFD_OPTION(9)

✨ enum iommufd_option 💅

okay so bestie, welcome to the Kernel API Manual — yes that's the manual name, we're being fancy today 🎀 — and today's main character is enum iommufd_option, which is the whole vibe behind ioctl(IOMMU_OPTION_RLIMIT_MODE) and ioctl(IOMMU_OPTION_HUGE_PAGES). Two whole options. Iconic. Let's go 🦋

✨ SYNOPSIS ✨

like, here's the shape of the thing, no cap:

enum iommufd_option {
    IOMMU_OPTION_RLIMIT_MODE ,
    IOMMU_OPTION_HUGE_PAGES

};

🌸 Constants 🌸

time for the actual deets, and yes there's only two, but they're both kinda important 👑

• IOMMU_OPTION_RLIMIT_MODE — this one changes how RLIMIT_MEMLOCK accounting works. lowkey powerful. the caller must have privilege to invoke this, so don't just show up without it 🙈 Value 0 (the default) means user based accounting, and value 1 uses process based accounting. also it's a global option, so object_id must be 0 — like, don't try to be cute with it 💀
• IOMMU_OPTION_HUGE_PAGES — value 1 (the default) allows contiguous pages to be combined when generating iommu mappings. value 0 disables the combining and everything gets mapped to PAGE_SIZE. honestly this can be useful for benchmarking 🧚 this one is a per-IOAS option, so object_id must be the IOAS ID — different rules, same queen energy ✨

🦋 SEE ALSO 🦋

this list is long and I respect it, so here's every single one, no skipping, fr fr 💖

Also peep the kernel file: ./include/uapi/linux/iommufd.h — that's where it lives, iykyk 🍓

• General ioctl format(9)
• struct iommu_destroy(9)
• struct iommu_ioas_alloc(9)
• struct iommu_iova_range(9)
• struct iommu_ioas_iova_ranges(9)
• struct iommu_ioas_allow_iovas(9)
• enum iommufd_ioas_map_flags(9)
• struct iommu_ioas_map(9)
• struct iommu_ioas_noiommu_get_pa(9)
• struct iommu_ioas_map_file(9)
• struct iommu_ioas_copy(9)
• struct iommu_ioas_unmap(9)
• enum iommufd_option_ops(9)
• struct iommu_option(9)
• enum iommufd_vfio_ioas_op(9)
• struct iommu_vfio_ioas(9)
• enum iommufd_hwpt_alloc_flags(9)
• enum iommu_hwpt_vtd_s1_flags(9)
• struct iommu_hwpt_vtd_s1(9)
• struct iommu_hwpt_arm_smmuv3(9)
• struct iommu_hwpt_amd_guest(9)
• enum iommu_hwpt_data_type(9)
• struct iommu_hwpt_alloc(9)
• enum iommu_hw_info_vtd_flags(9)
• struct iommu_hw_info_vtd(9)
• enum iommu_hw_info_arm_smmuv3_flags(9)
• struct iommu_hw_info_arm_smmuv3(9)
• struct iommu_hw_info_tegra241_cmdqv(9)
• struct iommu_hw_info_amd(9)
• enum iommu_hw_info_type(9)
• enum iommufd_hw_capabilities(9)
• enum iommufd_hw_info_flags(9)
• struct iommu_hw_info(9)
• struct iommu_hwpt_set_dirty_tracking(9)
• enum iommufd_hwpt_get_dirty_bitmap_flags(9)
• struct iommu_hwpt_get_dirty_bitmap(9)
• enum iommu_hwpt_invalidate_data_type(9)
• enum iommu_hwpt_vtd_s1_invalidate_flags(9)
• struct iommu_hwpt_vtd_s1_invalidate(9)
• struct iommu_viommu_arm_smmuv3_invalidate(9)
• struct iommu_hwpt_invalidate(9)
• enum iommu_hwpt_pgfault_flags(9)
• enum iommu_hwpt_pgfault_perm(9)
• struct iommu_hwpt_pgfault(9)
• enum iommufd_page_response_code(9)
• struct iommu_hwpt_page_response(9)
• struct iommu_fault_alloc(9)
• enum iommu_viommu_type(9)
• struct iommu_viommu_tegra241_cmdqv(9)
• struct iommu_viommu_alloc(9)
• struct iommu_vdevice_alloc(9)
• struct iommu_ioas_change_process(9)
• enum iommu_veventq_flag(9)
• struct iommufd_vevent_header(9)
• enum iommu_veventq_type(9)
• struct iommu_vevent_arm_smmuv3(9)
• struct iommu_vevent_tegra241_cmdqv(9)
• struct iommu_veventq_alloc(9)
• enum iommu_hw_queue_type(9)
• struct iommu_hw_queue_alloc(9)

and that's the whole page, bestie 🫶 you ate that. before you go — this lil masterpiece lives in ./include/uapi/linux, dated October 2026 ⭐ so like, bookmark it in your brain. mwah 💋🌈