MEMORY AND MAPPING OBJECTS(9)

💖 Memory and Mapping Objects 💖

okay so bestie, this is a page from the Kernel API Manual and it's literally all about how QTEE does memory sharing with Linux. it's giving "short but important", so let's get into it 🫶

✨ the whole vibe (DESCRIPTION) ✨

So QTEE uses memory objects for memory sharing with Linux. A memory object can be a standard dma_buf or a contiguous memory range, e.g., tee_shm. And bestie, a memory object only has to support one operation: map. When QTEE invokes it, a mapping object gets generated. And a mapping object also supports exactly one operation: unmap. one in, one out, iconic symmetry honestly 💅

Here's the flow, no cap:

1. To map a memory object, QTEE invokes the primordial object with the QCOMTEE_OBJECT_OP_MAP_REGION operation — see qcomtee_primordial_obj_dispatch for the receipts 👀
2. To unmap a memory object, QTEE releases the mapping object, and that call just calls qcomtee_mem_object_release. slay, cleanup handled ✨

🔥 why the map op lives in the primordial object 🔥

So the map operation is implemented in the primordial object as a privileged operation instead of qcomtee_mem_object_dispatch. and there's a real reason for that, bestie, listen:

On platforms without shm_bridge, a user can trick QTEE into writing to the kernel memory by passing a user object as a memory object and returning a random physical address as the result of the mapping request. 💀

so yeah — the map op being privileged is not a quirky little design choice, it's literally the thing standing between your kernel and chaos. do not move it. do not "clean it up". ngl that's the whole plot. 😭

🌈 SEE ALSO 🌈

• Kernel file ./drivers/tee/qcomtee/mem_obj.c — the code, go read it 👑
• qcomtee_memobj_param_to_object(9)
• qcomtee_mem_object_map(9)

that's the whole page, bestie, you ate it up 🎀

~ from ./drivers/tee/qcomtee, dated October 2026 — the Kernel API Manual era, we love a dated queen 💜