STRUCT IOMMU_IOTLB_GATHER(9)

💖 NAME 💖

okay bestie, welcome to struct iommu_iotlb_gather(9) — literally the range information for a pending IOTLB flush. That's the whole vibe: one iconic little struct holding the deets for a flush that hasn't happened yet. 🦋

✨ SYNOPSIS ✨

no cap, here's the shape:

struct iommu_iotlb_gather {
    unsigned long           start;
    unsigned long           end;
    union {
      size_t pgsize;
      struct {
        u8 leaf_levels_bitmap;
        u8 table_levels_bitmap;
      } pt;
    };
    struct iommu_pages_list freelist;
    bool queued;
 };

🎀 Members 🎀

• start — IOVA representing the start of the range to be flushed.
• end — IOVA representing the end of the range to be flushed (inclusive). inclusive, bestie — don't forget that part.
• {unnamed_union} — anonymous. it's giving mysterious unnamed-union energy, honestly.
• pgsize — The interval at which to perform the flush, only used by arm-smmu-v3.
• pt.leaf_levels_bitmap — Bitmap of generic_pt levels where leaf entries were unmapped. Bit 0 means the leaf only level. If 0 no leafs were unmapped.
• pt.table_levels_bitmap — Bitmap of generic_pt levels of table entries that were removed. Bit 0 is never set, bit 1 means a table of all leafs was removed. When freelist is empty this must be 0.
• freelist — Removed pages to free after sync, only used by iommupt.
• queued — True if the gather will be completed with a flush all.

🌸 Description 🌸

This structure is intended to be updated by multiple calls to the ->unmap function in struct iommu_ops before eventually being passed into ->iotlb_sync. Drivers can add pages to freelist to be freed after ->iotlb_sync or ->iotlb_flush_all have cleared all cached references to them. queued is set to indicate when ->iotlb_flush_all will be called later instead of ->iotlb_sync, so drivers may optimise accordingly.

🔥 SEE ALSO 🔥

Kernel file ./include/linux/iommu.h — also go say hi to these icons:

• 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_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_device(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)

mwah 💋 — source ./include/linux, version struct iommu_iotlb_gather(9), date October 2026. periodt. 🌈