amdgpu_pasid_alloc(9)

💅 amdgpu_pasid_alloc(9) — straight out of the Kernel API Manual, bestie

okay so picture this: it's a kernel API manual page, section 9, and the star of the show is amdgpu_pasid_alloc. literally all the driver girls are using it. let's get into it 🎀

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✨ NAME ✨

amdgpu_pasid_alloc — allocate a PASID. that's it, that's the whole vibe. one job, and she does it 💅

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🦋 SYNOPSIS 🦋

int amdgpu_pasid_alloc (unsigned int bits , struct amdgpu_fpriv *fpriv );

yes she takes two args. yes she returns an int. no we're not going to be weird about it 💖

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🌸 ARGUMENTS 🌸

• bits — the number of PASID bits that the hardware supports. it's giving "how much room do we have to work with" energy. respect her, she's a unsigned int ✨
• fpriv — the DRM file private, and it gets associated with the PASID. struct amdgpu_fpriv *. main character pointer energy fr fr 👑

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🔥 DESCRIPTION 🔥

so what's actually happening under the hood? she uses the kernel's XArray cyclic allocator — iconic, love that for her — and she allocates sequentially, with automatic wrap-around. so when she runs out the end, she doesn't panic, she just loops back around like it's nothing. no cap, that's the whole trick 🌀

wrap-around is a feature, not a bug, bestie. internalize that 🫶

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⭐ RETURN ⭐

on success you get the allocated PASID back (yay 🎉). on failure you get a negative error code, which is the kernel's way of saying "not today" 😭

ngl, always check your return value. a negative error code is not a PASID and you will have a bad time if you treat it like one 💀

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👑 SEE ALSO 👑

the kernel file in question, aka where the magic lives:

./drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c

and the whole friend group 🧚 — every single one of these, in order:

• amdgpu_pasid_free(9)
• amdgpu_pasid_clear_owner(9)
• amdgpu_pasid_lock(9)
• amdgpu_pasid_unlock(9)
• amdgpu_pasid_get_fpriv_locked(9)
• amdgpu_pasid_free_delayed(9)
• amdgpu_vmid_had_gpu_reset(9)
• amdgpu_vmid_grab_idle(9)
• amdgpu_vmid_grab_reserved(9)
• amdgpu_vmid_grab_used(9)
• amdgpu_vmid_grab(9)
• amdgpu_vmid_reset(9)
• amdgpu_vmid_reset_all(9)
• amdgpu_vmid_mgr_init(9)
• amdgpu_vmid_mgr_fini(9)
• amdgpu_pasid_mgr_cleanup(9)

the vmid girlies and the pasid girlies, all in one squad. iykyk 🌈

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and that's the page!! 🍓 sourced from ./drivers/gpu/drm/amd/amdgpu, dated October 2026, and the manual name is amdgpu_pasid_alloc(9) in case you forgot already 🙈 mwah, go allocate something 💜