STRUCT XE_VRAM_REGION(9)

✨ struct xe_vram_region(9) ✨

okay bestie, buckle up 💅 this is a page from the Kernel API Manual, and it's literally the whole lore on struct xe_vram_region — like, what even is it?

🌸 NAME 🌸

struct xe_vram_region — the memory region structure. fr fr, this one is used to describe a memory region in an xe device, like HBM memory or CXL extension memory. no cap, that's the whole vibe 🫶

🎀 SYNOPSIS 🎀

struct xe_vram_region {
    struct xe_device *xe;
    u8 id;
    resource_size_t io_start;
    resource_size_t io_size;
    resource_size_t dpa_base;
    resource_size_t usable_size;
    resource_size_t actual_physical_size;
    void __iomem *mapping;
    struct xe_ttm_vram_mgr ttm;
    u32 placement;
  #if IS_ENABLED(CONFIG_DRM_XE_PAGEMAP);
    struct xe_migrate *migrate;
    struct drm_pagemap_cache *dpagemap_cache;
  #endif;
 };

💖 Members 💖

okay so here's the cast of characters, and yes every single one of them matters 👑

• xe — back pointer to the xe device. it's giving "who's your parent" energy 🌈
• id — the VRAM region instance id. and the value should be unique for a VRAM region, periodt 💀 no duplicates allowed bestie.
• io_start — IO start address of this VRAM instance ✨
• io_size — IO size of this VRAM instance. this one represents how much of this VRAM we can actually access via the CPU through the VRAM BAR. lowkey iconic detail: this can be smaller than usable_size, in which case only part of VRAM is CPU accessible (typically the first 256M). this configuration is known as small-bar. yes that's a real name, iykyk 🧚
• dpa_base — this memory region's DPA (device physical address) base 🦋
• usable_size — usable size of VRAM. it's the usable size of VRAM excluding reserved portions (e.g stolen mem) 🙈
• actual_physical_size — the actual VRAM size. and that's the actual VRAM size including reserved portions (e.g stolen mem) 🔥
• mapping — pointer to VRAM mappable space ⭐
• ttm — the VRAM TTM manager 👑
• placement — TTM placement dedicated for this region 💜
• migrate — back pointer to migrate 🎀
• dpagemap_cache — the drm_pagemap cache. that's it, that's the whole description, she said what she said 💅

heads up bestie: migrate and dpagemap_cache only exist when IS_ENABLED(CONFIG_DRM_XE_PAGEMAP) is true, so don't come for them if that config is off 🫶

🌈 SEE ALSO 🌈

if you wanna read the source (and honestly, obsessed), go look at the kernel file ./drivers/gpu/drm/xe/xe_vram_types.h ✨

kisses bestie, this one's a wrap 💖 this page is comin' at you straight from ./drivers/gpu/drm/xe, dated October 2026, in the good ol' Kernel API Manual — slay, and happy hacking 🎀🦋