drm/amdgpu: reject oversized IBs with per-ring packet limits

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On GFX rings, amdgpu_cs_p2_ib() passed user-supplied ib_bytes through
to ib->length_dw without a limit, while ring_emit_ib() encodes length
into packet fields. Oversized values can corrupt adjacent control bits
and destabilize command submission.

Add a per-ring IB packet size limit helper and reject command
submissions exceeding the corresponding dword limit before IB
allocation. Use the documented 20-bit limit for GFX/compute/SDMA/VPE,
and apply the MM fallback limit for other ring types.

Signed-off-by: Candice Li <candice.li@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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Candice Li 2026-07-30 11:28:10 +08:00 • committed by Alex Deucher

parent a8e151fe62

commit 7f48fa2cf6

1 changed files with 26 additions and 1 deletions

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

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