STRUCT IOMMU_DEVICE(9)

💖 NAME 💖

struct iommu_device — the IOMMU core's whole entire representation of one IOMMU hardware instance ✨ (this is from the Kernel API Manual, bestie, section 9, we love a documentation era)

🌸 SYNOPSIS 🌸

okay so here's the struct, literally exactly as it is, do not come for me about the indentation:

struct iommu_device {
    struct list_head list;
    const struct iommu_ops *ops;
    struct fwnode_handle *fwnode;
    struct device *dev;
    struct iommu_group *singleton_group;
    u32 max_pasids;
    bool ready;
 };

🎀 Members 🎀

• list — the iommu-core uses this to keep a list of registered iommus, like a little roster, a group chat of iommus if you will 🫶
• ops — the iommu-ops for talking to this iommu. this is the "how do i actually communicate with you" field 💅
• dev — a struct device for sysfs handling. yes bestie, sysfs has needs 🦋
• singleton_group — used internally for drivers that have only one group. one group, one girl, main character energy 👑
• max_pasids — number of supported PASIDs. that's the number, that's the whole field, no notes 🔥
• ready — set once iommu_device_register has completed successfully. so like, it's not ready until it's ready, periodt ⭐

real talk: fwnode is in the struct up there 👆 but this page doesn't give it its own little blurb. not me leaving a field undescribed, it's just how the page is 🙈

🌈 SEE ALSO 🌈

the kernel file is ./include/linux/iommu.h, and then there's a whole crew of related pages, all section (9), all iconic in their own way:

• struct iommu_fault_page_request(9)
• struct iommu_fault(9)
• enum iommu_page_response_code(9)
• struct iommu_page_response(9)
• struct iopf_queue(9)
• struct iommu_resv_region(9)
• struct iommu_iotlb_gather(9)
• struct iommu_dirty_bitmap(9)
• struct iommu_dirty_ops(9)
• struct iommu_user_data(9)
• struct iommu_user_data_array(9)
• __iommu_copy_struct_from_user(9)
• iommu_copy_struct_from_user(9)
• __iommu_copy_struct_from_user_array(9)
• iommu_copy_struct_from_user_array(9)
• iommu_copy_struct_from_full_user_array(9)
• __iommu_copy_struct_to_user(9)
• iommu_copy_struct_to_user(9)
• struct iommu_ops(9)
• struct iommu_domain_ops(9)
• struct iommu_fault_param(9)
• struct dev_iommu(9)
• iommu_iotlb_gather_is_disjoint(9)
• iommu_iotlb_gather_add_range(9)
• iommu_iotlb_gather_add_page(9)
• struct iommu_fwspec(9)
• struct iommu_sva(9)
• iommu_map_sgtable(9)

okay that's the whole page, mwah 💋 this lil number lives in ./include/linux and it's dated October 2026 — go read it, it ate, no cap 🍓🧚💜