drm/amdkfd: Add TLB flush after MES queue eviction/suspension

MES (Micro Engine Scheduler) does not perform heavy-weight TLB
invalidation after unmapping queues, unlike HWS which does this
automatically. This causes a race condition where in-flight DMA
descriptors can access memory that has been unmapped, leading to page
faults and GPU queue hangs during SVM page migration.

The issue manifests as KFDSVMRangeTest.MultiThreadMigrationTest
failures on gfx1151 (Strix Point) with XNACK mode 1 enabled - the GPU
compute queue hangs with packets submitted but never consumed.

Add kfd_flush_tlb() calls after MES queue removal in two locations:
- evict_process_queues_cpsch(): after all queues removed during eviction
- suspend_queues(): after debug/criu queue suspension (with mem_fence barrier)

This ensures all in-flight memory accesses from unmapped queues are
flushed before memory is freed or migrated.

Signed-off-by: Priya Hosur <Priya.Hosur@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit f5c4f88e0f9c45a8fb9dfac0c1df726c95e41b77)
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 4bc947c3bd0d..9811e4e10291 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -1455,6 +1455,14 @@ static int evict_process_queues_cpsch(struct device_queue_manager *dqm,
 		dqm_evict_mqd_bo(dqm, q);
 	}
 
+	/*
+	 * Heavy-weight TLB flush after MES removes queues to ensure
+	 * in-flight memory accesses complete before memory is freed/migrated.
+	 * HWS does this automatically, MES does not.
+	 */
+	if (dqm->dev->kfd->shared_resources.enable_mes)
+		kfd_flush_tlb(pdd);
+
 	if (!dqm->dev->kfd->shared_resources.enable_mes) {
 		pdd->last_evict_timestamp = get_jiffies_64();
 		retval = execute_queues_cpsch(dqm,
@@ -3746,8 +3754,11 @@ int suspend_queues(struct kfd_process *p,
 		if (!per_device_suspended) {
 			dqm_unlock(dqm);
 			mutex_unlock(&p->event_mutex);
-			if (total_suspended)
+			if (total_suspended) {
 				amdgpu_amdkfd_debug_mem_fence(dqm->dev->adev);
+				/* Heavy-weight TLB flush after MES suspends queues */
+				kfd_flush_tlb(pdd);
+			}
 			continue;
 		}