[PATCH v3 2/2] drm/amdgpu: Add TLB flush after MES user queue unmap

[Priya Hosur <Priya.Hosur@amd.com>]

Similar to the KFD fix, MES does not perform heavy-weight TLB
invalidation after unmapping user queues. Add
amdgpu_gmc_flush_gpu_tlb_pasid() after MES unmap succeeds in
amdgpu_userq_unmap_helper() to ensure in-flight memory accesses
complete before memory is freed or migrated.

Change-Id: I94fe2c84547723b6b73816ce8d727a54bd773a6a
Signed-off-by: Priya Hosur <Priya.Hosur@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index 6d3ed55e9ab4..9fcf15d69b7b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -375,6 +375,12 @@ static int amdgpu_userq_unmap_helper(struct amdgpu_usermode_queue *queue)
 		} else {
 			trace_amdgpu_userq_state_changed(queue, AMDGPU_USERQ_STATE_UNMAPPED);
 			queue->state = AMDGPU_USERQ_STATE_UNMAPPED;
+			/*
+			 * Heavy-weight TLB flush after MES unmaps queue to ensure
+			 * in-flight memory accesses complete before memory is freed/migrated.
+			 * MES does not do this automatically unlike HWS.
+			 */
+			amdgpu_gmc_flush_gpu_tlb_pasid(adev, queue->vm->pasid, 2, true, 0);
 		}
 	}
 
-- 
2.43.0