Re: [PATCH 00/30] Rework GPU TLB invalidation

On Mon, Aug 24, 2026 at 6:20 PM Alex Deucher <[email protected]> wrote:
>
> GMC 9-12 use KIQ or MES for TLB invalidations to avoid using MMIO which would
> require disallowing GFXOFF.  KIQ and MES are management queues however and if
> they hang, they cannot be recovered by a queue reset since they are the
> mechanisms which handle queue resets.  Since using KIQ or MES will exit GFXOFF
> anyway, explicitly disallow it on the MMIO path and use that. Next, switch to
> using SDMA for TLB invalidations.  SDMA 4.4.x and newer have special packets
> specifically for this purpose.  If SDMA hangs while doing the invalidation for
> some reason, it's easier to reset the SDMA queue than KIQ or MES.  Finally,
> most of the TLB invalidation code between GMC 9 through 12 was identical, so
> move it to common GMC helpers and remove the IP specific code.  If the SMDA
> and MMIO pathes prove to be stable, the KIQ pathes can be removed in the future
> to further simplify things. SDMA 4.x could also be updated to support PASID
> invalidation via SDMA using either the new packet (SDMA 4.4.x) or via
> REG_WRITE/REG_WAIT packets (SDMA 4.0.x).

Some older gfxhubs and mmhubs will also need this patch:
https://gitlab.freedesktop.org/agd5f/linux/-/commit/a1f1823a8ecd80bee660244def5f20179926fe8c

Updated patches with that included here:
https://gitlab.freedesktop.org/agd5f/linux/-/commits/tlb_inv_rework?ref_type=heads

Alex


>
>
> Alex Deucher (30):
>   drm/amdgpu/gmc9: disallow gfxoff around TLB flushes
>   drm/amdgpu/gmc10: disallow gfxoff around TLB flushes
>   drm/amdgpu/gmc11: disallow gfxoff around TLB flushes
>   drm/amdgpu/gmc12: disallow gfxoff around TLB flushes
>   drm/amdgpu: add a gmc flag for using MMIO for TLB flush
>   drm/amdgpu/gmc9: use MMIO for TLB flushes
>   drm/amdgpu/gmc10: use MMIO for TLB flushes
>   drm/amdgpu/gmc11: use MMIO for TLB flushes
>   drm/amdgpu/gmc12: use MMIO for TLB flushes
>   drm/amdgpu: add a buffer funcs callback for TLB invalidation
>   drm/amdgpu/sdma5.0: add tlb invalidation buffer func callback
>   drm/amdgpu/sdma5.2: add tlb invalidation buffer func callback
>   drm/amdgpu/sdma6: add tlb invalidation buffer func callback
>   drm/amdgpu/sdma7: add tlb invalidation buffer func callback
>   drm/amdgpu: simplify amdgpu_gmc_flush_gpu_tlb()
>   drm/amdgpu: add tlb invalidation method enum
>   drm/amdgpu: plumb tlb inv method in amdgpu_gmc_flush_gpu_tlb_gart()
>   drm/amdgpu: uplevel reset check in amdgpu_gmc_flush_gpu_tlb_gart()
>   drm/amdgpu/gmc: add new callback to lookup vmid to pasid mapping
>   drm/amdgpu: add a gmc callback for the inv semaphore
>   drm/amdgpu/gmc: rework pasid flushing
>   drm/amdgpu/gmc9: use SDMA for gart TLB invalidation
>   drm/amdgpu/gmc10: use SDMA for gart TLB invalidation
>   drm/amdgpu/gmc11: use SDMA for gart TLB invalidation
>   drm/amdgpu/gmc12: use SDMA for gart TLB invalidation
>   drm/amdgpu/gmc10: use SDMA for pasid TLB invalidation
>   drm/amdgpu/gmc11: use SDMA for pasid TLB invalidation
>   drm/amdgpu/gmc12: use MES or SDMA for pasid TLB invalidation
>   drm/amdgpu/gmc12: drop MES tlb inv in gmc callbacks
>   drm/amdgpu/gmc: add helpers for various tlb inv functions
>
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c |   2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c  | 486 +++++++++++++++++++----
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h  |  33 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h |  18 +
>  drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c   |   2 +
>  drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c   | 202 +---------
>  drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c   | 207 +---------
>  drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c   | 250 ++----------
>  drivers/gpu/drm/amd/amdgpu/gmc_v12_1.c   | 225 +----------
>  drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c    | 114 +-----
>  drivers/gpu/drm/amd/amdgpu/mes_v12_0.c   |   4 +
>  drivers/gpu/drm/amd/amdgpu/mes_v12_1.c   |   4 +
>  drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c   |  49 +++
>  drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c   |  49 +++
>  drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c   |  49 +++
>  drivers/gpu/drm/amd/amdgpu/sdma_v7_0.c   |  48 +++
>  16 files changed, 747 insertions(+), 995 deletions(-)
>
> --
> 2.55.0
>