drm/amdkfd: Fix suspend/resume issue on Carrizo v2

When we do suspend/resume through "sudo pm-suspend" while there is
HSA activity running, upon resume we will encounter HWS hanging, which
is caused by memory read/write failures. The root cause is that when
suspend, we neglected to unbind pasid from kfd device.

Another major change is that the bind/unbinding is changed to be
performed on a per process basis, instead of whether there are queues
in dqm.

v2:
- free IOMMU device if kfd_bind_processes_to_device fails in kfd_resume
- add comments to kfd_bind/unbind_processes_to/from_device
- minor cleanups

Signed-off-by: Yong Zhao <yong.zhao@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/gpu/drm/amd/amdkfd/kfd_device.c

@@ -184,7 +184,7 @@ static void iommu_pasid_shutdown_callback(struct pci_dev *pdev, int pasid)
 	struct kfd_dev *dev = kfd_device_by_pci_dev(pdev);
 
 	if (dev)
-		kfd_unbind_process_from_device(dev, pasid);
+		kfd_process_iommu_unbind_callback(dev, pasid);
 }
 
 /*
@@ -332,12 +332,16 @@ void kgd2kfd_device_exit(struct kfd_dev *kfd)
 
 void kgd2kfd_suspend(struct kfd_dev *kfd)
 {
-	if (kfd->init_complete) {
-		kfd->dqm->ops.stop(kfd->dqm);
-		amd_iommu_set_invalidate_ctx_cb(kfd->pdev, NULL);
-		amd_iommu_set_invalid_ppr_cb(kfd->pdev, NULL);
-		amd_iommu_free_device(kfd->pdev);
-	}
+	if (!kfd->init_complete)
+		return;
+
+	kfd->dqm->ops.stop(kfd->dqm);
+
+	kfd_unbind_processes_from_device(kfd);
+
+	amd_iommu_set_invalidate_ctx_cb(kfd->pdev, NULL);
+	amd_iommu_set_invalid_ppr_cb(kfd->pdev, NULL);
+	amd_iommu_free_device(kfd->pdev);
 }
 
 int kgd2kfd_resume(struct kfd_dev *kfd)
@@ -362,6 +366,10 @@ static int kfd_resume(struct kfd_dev *kfd)
 	amd_iommu_set_invalid_ppr_cb(kfd->pdev,
 				     iommu_invalid_ppr_cb);
 
+	err = kfd_bind_processes_to_device(kfd);
+	if (err)
+		goto processes_bind_error;
+
 	err = kfd->dqm->ops.start(kfd->dqm);
 	if (err) {
 		dev_err(kfd_device,
@@ -373,6 +381,7 @@ static int kfd_resume(struct kfd_dev *kfd)
 	return err;
 
 dqm_start_error:
+processes_bind_error:
 	amd_iommu_free_device(kfd->pdev);
 
 	return err;

drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c

@@ -670,7 +670,6 @@ static int initialize_cpsch(struct device_queue_manager *dqm)
 
 static int start_cpsch(struct device_queue_manager *dqm)
 {
-	struct device_process_node *node;
 	int retval;
 
 	retval = 0;
@@ -697,11 +696,6 @@ static int start_cpsch(struct device_queue_manager *dqm)
 
 	init_interrupts(dqm);
 
-	list_for_each_entry(node, &dqm->queues, list)
-		if (node->qpd->pqm->process && dqm->dev)
-			kfd_bind_process_to_device(dqm->dev,
-						node->qpd->pqm->process);
-
 	execute_queues_cpsch(dqm, true);
 
 	return 0;
@@ -714,15 +708,8 @@ fail_packet_manager_init:
 
 static int stop_cpsch(struct device_queue_manager *dqm)
 {
-	struct device_process_node *node;
-	struct kfd_process_device *pdd;
-
 	destroy_queues_cpsch(dqm, true, true);
 
-	list_for_each_entry(node, &dqm->queues, list) {
-		pdd = qpd_to_pdd(node->qpd);
-		pdd->bound = false;
-	}
 	kfd_gtt_sa_free(dqm->dev, dqm->fence_mem);
 	pm_uninit(&dqm->packets);
 

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -432,6 +432,13 @@ struct qcm_process_device {
 	uint32_t sh_hidden_private_base;
 };
 
+
+enum kfd_pdd_bound {
+	PDD_UNBOUND = 0,
+	PDD_BOUND,
+	PDD_BOUND_SUSPENDED,
+};
+
 /* Data that is per-process-per device. */
 struct kfd_process_device {
 	/*
@@ -456,7 +463,7 @@ struct kfd_process_device {
 	uint64_t scratch_limit;
 
 	/* Is this process/pasid bound to this device? (amd_iommu_bind_pasid) */
-	bool bound;
+	enum kfd_pdd_bound bound;
 
 	/* This flag tells if we should reset all
 	 * wavefronts on process termination
@@ -547,8 +554,10 @@ struct kfd_process *kfd_get_process(const struct task_struct *);
 struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid);
 
 struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
-							struct kfd_process *p);
-void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid);
+						struct kfd_process *p);
+int kfd_bind_processes_to_device(struct kfd_dev *dev);
+void kfd_unbind_processes_from_device(struct kfd_dev *dev);
+void kfd_process_iommu_unbind_callback(struct kfd_dev *dev, unsigned int pasid);
 struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p);
 struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -174,9 +174,10 @@ static void kfd_process_wq_release(struct work_struct *work)
 		if (pdd->reset_wavefronts)
 			dbgdev_wave_reset_wavefronts(pdd->dev, p);
 
-		amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
-		list_del(&pdd->per_device_list);
+		if (pdd->bound == PDD_BOUND)
+			amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
 
+		list_del(&pdd->per_device_list);
 		kfree(pdd);
 	}
 
@@ -351,9 +352,9 @@ struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 
 	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
 		if (pdd->dev == dev)
-			break;
+			return pdd;
 
-	return pdd;
+	return NULL;
 }
 
 struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,
@@ -368,6 +369,7 @@ struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,
 		INIT_LIST_HEAD(&pdd->qpd.priv_queue_list);
 		pdd->qpd.dqm = dev->dqm;
 		pdd->reset_wavefronts = false;
+		pdd->bound = PDD_UNBOUND;
 		list_add(&pdd->per_device_list, &p->per_device_data);
 	}
 
@@ -393,19 +395,91 @@ struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	if (pdd->bound)
+	if (pdd->bound == PDD_BOUND) {
 		return pdd;
+	} else if (unlikely(pdd->bound == PDD_BOUND_SUSPENDED)) {
+		pr_err("Binding PDD_BOUND_SUSPENDED pdd is unexpected!\n");
+		return ERR_PTR(-EINVAL);
+	}
 
 	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
 	if (err < 0)
 		return ERR_PTR(err);
 
-	pdd->bound = true;
+	pdd->bound = PDD_BOUND;
 
 	return pdd;
 }
 
-void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
+/*
+ * Bind processes do the device that have been temporarily unbound
+ * (PDD_BOUND_SUSPENDED) in kfd_unbind_processes_from_device.
+ */
+int kfd_bind_processes_to_device(struct kfd_dev *dev)
+{
+	struct kfd_process_device *pdd;
+	struct kfd_process *p;
+	unsigned int temp;
+	int err = 0;
+
+	int idx = srcu_read_lock(&kfd_processes_srcu);
+
+	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
+		mutex_lock(&p->mutex);
+		pdd = kfd_get_process_device_data(dev, p);
+		if (pdd->bound != PDD_BOUND_SUSPENDED) {
+			mutex_unlock(&p->mutex);
+			continue;
+		}
+
+		err = amd_iommu_bind_pasid(dev->pdev, p->pasid,
+				p->lead_thread);
+		if (err < 0) {
+			pr_err("unexpected pasid %d binding failure\n",
+					p->pasid);
+			mutex_unlock(&p->mutex);
+			break;
+		}
+
+		pdd->bound = PDD_BOUND;
+		mutex_unlock(&p->mutex);
+	}
+
+	srcu_read_unlock(&kfd_processes_srcu, idx);
+
+	return err;
+}
+
+/*
+ * Temporarily unbind currently bound processes from the device and
+ * mark them as PDD_BOUND_SUSPENDED. These processes will be restored
+ * to PDD_BOUND state in kfd_bind_processes_to_device.
+ */
+void kfd_unbind_processes_from_device(struct kfd_dev *dev)
+{
+	struct kfd_process_device *pdd;
+	struct kfd_process *p;
+	unsigned int temp, temp_bound, temp_pasid;
+
+	int idx = srcu_read_lock(&kfd_processes_srcu);
+
+	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
+		mutex_lock(&p->mutex);
+		pdd = kfd_get_process_device_data(dev, p);
+		temp_bound = pdd->bound;
+		temp_pasid = p->pasid;
+		if (pdd->bound == PDD_BOUND)
+			pdd->bound = PDD_BOUND_SUSPENDED;
+		mutex_unlock(&p->mutex);
+
+		if (temp_bound == PDD_BOUND)
+			amd_iommu_unbind_pasid(dev->pdev, temp_pasid);
+	}
+
+	srcu_read_unlock(&kfd_processes_srcu, idx);
+}
+
+void kfd_process_iommu_unbind_callback(struct kfd_dev *dev, unsigned int pasid)
 {
 	struct kfd_process *p;
 	struct kfd_process_device *pdd;
@@ -438,15 +512,6 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
 		pdd->reset_wavefronts = false;
 	}
 
-	/*
-	 * Just mark pdd as unbound, because we still need it
-	 * to call amd_iommu_unbind_pasid() in when the
-	 * process exits.
-	 * We don't call amd_iommu_unbind_pasid() here
-	 * because the IOMMU called us.
-	 */
-	pdd->bound = false;
-
 	mutex_unlock(&p->mutex);
 }