[PATCH 1/6] drm/amdgpu/bu: Use legacy TLB flush for gfx943

[Christian König]

All those workaround were only to be used during bringup and are not 
supposed for upstreaming.

Especially we probably don't want the module parameter to override the 
MTYPE used in the VM mappings in a release.

Christian.

Am 10.05.23 um 19:56 schrieb Alex Deucher:
> From: Graham Sider <Graham.Sider at amd.com>
>
> Invalidate TLBs via a legacy flush request (flush_type=0) prior to the
> heavyweight flush requests (flush_type=2) in gmc_v9_0.c. This is
> temporarily required to mitigate a bug causing CPC UTCL1 to return stale
> translations after invalidation requests in address range mode.
>
> Signed-off-by: Graham Sider <Graham.Sider at amd.com>
> Reviewed-by: Philip Yang <Philip.Yang at amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index f000e0e89bd0..d28ffdb07ae6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -833,6 +833,14 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev, uint32_t vmid,
>   		 */
>   		inv_req = gmc_v9_0_get_invalidate_req(vmid, 2);
>   		inv_req2 = gmc_v9_0_get_invalidate_req(vmid, flush_type);
> +	} else if (flush_type == 2 &&
> +		   adev->ip_versions[GC_HWIP][0] == IP_VERSION(9, 4, 3)) {
> +		/* FIXME: Temporarily add a legacy flush (type 0) before heavyweight
> +		 * flush for gfx943 to mitigate a bug which causes CPC UTCL1 to return
> +		 * stale translations even after TLB heavyweight flush.
> +		 */
> +		inv_req = gmc_v9_0_get_invalidate_req(vmid, 0);
> +		inv_req2 = gmc_v9_0_get_invalidate_req(vmid, flush_type);
>   	} else {
>   		inv_req = gmc_v9_0_get_invalidate_req(vmid, flush_type);
>   		inv_req2 = 0;
> @@ -976,6 +984,15 @@ static int gmc_v9_0_flush_gpu_tlb_pasid(struct amdgpu_device *adev,
>   		if (vega20_xgmi_wa)
>   			kiq->pmf->kiq_invalidate_tlbs(ring,
>   						      pasid, 2, all_hub);
> +
> +		/* FIXME: Temporarily add a legacy flush (type 0) before heavyweight
> +		 * flush for gfx943 to mitigate a bug which causes CPC UTCL1 to return
> +		 * stale translations even after TLB heavyweight flush.
> +		 */
> +		if (flush_type == 2 && adev->ip_versions[GC_HWIP][0] == IP_VERSION(9, 4, 3))
> +			kiq->pmf->kiq_invalidate_tlbs(ring,
> +						pasid, 0, all_hub);
> +
>   		kiq->pmf->kiq_invalidate_tlbs(ring,
>   					pasid, flush_type, all_hub);
>   		r = amdgpu_fence_emit_polling(ring, &seq, MAX_KIQ_REG_WAIT);