STRUCT DRM_GPUVM(9)

💜 struct drm_gpuvm — DRM GPU VA Manager 💜

okay so this is from the Kernel API Manual, and bestie, it's the whole struct drm_gpuvm, like, the actual DRM GPU VA Manager. it's giving "one struct to rule the whole virtual address space" and honestly? iconic. let's get into it 🫶

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✨ NAME ✨

struct drm_gpuvm — the DRM GPU VA Manager, fr fr. this is the main character of GPU virtual address space management 💅

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🌸 SYNOPSIS 🌸

struct drm_gpuvm {
    const char *name;
    enum drm_gpuvm_flags flags;
    struct drm_device *drm;
    u64 mm_start;
    u64 mm_range;
    struct {
      struct rb_root_cached tree;
      struct list_head list;
    } rb;
    struct kref kref;
    struct drm_gpuva kernel_alloc_node;
    const struct drm_gpuvm_ops *ops;
    struct drm_gem_object *r_obj;
    struct {
      struct list_head list;
      struct list_head *local_list;
      spinlock_t lock;
    } extobj;
    struct {
      struct list_head list;
      struct list_head *local_list;
      spinlock_t lock;
    } evict;
    struct llist_head bo_defer;
 };

like, look at all those nested anonymous structs. the structure. the nesting. highkey obsessed 🦋

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🎀 Members 🎀

okay bestie, member by member, no skipping, no cap:

• name — the name of the DRM GPU VA space. yes it's just a string. yes it's still the moment 💫
• flags — the drm_gpuvm_flags of this GPUVM. the vibe check of the whole VM, basically ✨
• drm — the drm_device this VM lives in. its home. its whole address 🏠
• mm_start — start of the VA space. where it all begins 🥺
• mm_range — length of the VA space. how much room we're working with 📏
• rb — structures to track drm_gpuva entries 💖
  • rb.tree — the rb-tree to track GPU VA mappings 🌳
  • rb.list — the list_head to track GPU VA mappings 📋
• kref — reference count of this object. the classic "who's still holding a ref" situation 🙈
• kernel_alloc_node — a drm_gpuva representing the address space cutout reserved for the kernel. kernel gets its own lil VIP section 👑
• ops — drm_gpuvm_ops providing the split/merge steps to drivers. the driver's cheat sheet for splitting and merging, lowkey essential 💅
• r_obj — Resv GEM object; representing the GPUVM's common dma_resv. one shared reservation object for everybody 🤝
• extobj — structure holding the extobj list 📦
  • extobj.list — list_head storing drm_gpuvm_bos serving as external object 🌈
  • extobj.local_list — pointer to the local list temporarily storing entries from the external object list. a lil temporary holding pen 🍼
  • extobj.lock — spinlock to protect the extobj list 🔒
• evict — structure holding the evict list and evict list lock 🧹
  • evict.list — list_head storing drm_gpuvm_bos currently being evicted 👋
  • evict.local_list — pointer to the local list temporarily storing entries from the evicted object list. again: temporary pen, but for the evicted ones 🚪
  • evict.lock — spinlock to protect the evict list 🔐
• bo_defer — structure holding vm_bos that need to be destroyed. cleanup crew energy 💀

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🔥 Description 🔥

so the DRM GPU VA Manager keeps track of a GPU's virtual address space by using maple_tree structures. love that for it. typically, this structure is embedded in bigger driver structures — it's not out here alone, it's part of a friend group 🧚

drivers can pass addresses and ranges in an arbitrary unit, e.g. bytes or pages. literally whatever unit, the manager does not care 💅

there should be one manager instance per GPU virtual address space. one. per. space. no sharing, no splitting, periodt 👑

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👀 SEE ALSO 👀

the whole squad, a.k.a. the kernel file ./include/drm/drm_gpuvm.h and everybody in it:

enum drm_gpuva_flags(9), struct drm_gpuva(9), drm_gpuva_invalidate(9), drm_gpuva_invalidated(9), enum drm_gpuvm_flags(9), drm_gpuvm_get(9), drm_gpuvm_resv_protected(9), drm_gpuvm_immediate_mode(9), drm_gpuvm_resv(9), drm_gpuvm_resv_obj(9), drm_gpuvm_is_extobj(9), drm_gpuvm_for_each_va_range(9), drm_gpuvm_for_each_va_range_safe(9), drm_gpuvm_for_each_va(9), drm_gpuvm_for_each_va_safe(9), struct drm_gpuvm_exec(9), drm_gpuvm_exec_unlock(9), drm_gpuvm_exec_resv_add_fence(9), drm_gpuvm_exec_validate(9), struct drm_gpuvm_bo(9), drm_gpuvm_bo_get(9), drm_gpuvm_bo_gem_evict(9), drm_gpuvm_bo_for_each_va(9), drm_gpuvm_bo_for_each_va_safe(9), enum drm_gpuva_op_type(9), struct drm_gpuva_op_map(9), struct drm_gpuva_op_unmap(9), struct drm_gpuva_op_remap(9), struct drm_gpuva_op_prefetch(9), struct drm_gpuva_op(9), struct drm_gpuva_ops(9), drm_gpuva_for_each_op(9), drm_gpuva_for_each_op_safe(9), drm_gpuva_for_each_op_from_reverse(9), drm_gpuva_for_each_op_reverse(9), drm_gpuva_first_op(9), drm_gpuva_last_op(9), drm_gpuva_prev_op(9), drm_gpuva_next_op(9), struct drm_gpuvm_map_req(9), struct drm_gpuvm_ops(9), drm_gpuva_op_remap_to_unmap_range(9)

that's a whole friend group and they're all invited to the group chat 😭💖

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ngl this page came from ./include/drm and it's dated October 2026, so it's from the future AND the headers. slay. okay bye bestie, go manage those virtual addresses 💜✨🎀