EXPOSING MMIO REGIONS TO USERSPACE(9)

💅 Exposing MMIO regions to userspace 💅

hey bestie, welcome to the Kernel API Manual — this is the (9) page about letting userspace peek at MMIO regions, and we’re gonna make it make sense, fr fr. ✨

In certain cases, the driver may allow userspace to mmap a portion of the hardware registers. Slay, but like… responsibly. 🫶

This can be done as follows:

1. Call xe_mmio_gem_create to create a GEM object with an mmap-able fake offset. 🎀
2. Use xe_mmio_gem_mmap_offset on the created GEM object to retrieve the fake offset. 🔍
3. Provide the fake offset to userspace. 📬
4. Userspace can call mmap with the fake offset. The length provided to mmap must match the size of the GEM object. 📏
5. When the region is no longer needed, call xe_mmio_gem_destroy to release the GEM object. 🧹

NOTE: The exposed MMIO region must be page-aligned with regards to its BAR offset and size. 💅

WARNING: Exposing MMIO regions to userspace can have security and stability implications. Make sure not to expose any sensitive registers. 🚨 This one is not a vibe — be careful, bestie.

👀 SEE ALSO 👀

• Kernel file ./drivers/gpu/drm/xe/xe_mmio_gem.c
• xe_mmio_gem_create(9)
• xe_mmio_gem_mmap_offset(9)
• xe_mmio_gem_destroy(9)

mwah 💋 this page’s source/version is ./drivers/gpu/drm/xe, dated October 2026. 💖