drm/amdkfd: Add static user-mode queues support

This patch adds support for static user-mode queues in QCM.
Queues which are designated as static can NOT be preempted by
the CP microcode when it is executing its scheduling algorithm.

This is needed for supporting the debugger feature, because we
can't allow the CP to preempt queues which are currently being debugged.

The number of queues that can be designated as static is limited by the
number of HQDs (Hardware Queue Descriptors).

Signed-off-by: Yair Shachar <yair.shachar@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

1 files changed, 31 insertions, 7 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 4e215bd4d41f..a5dc8228b6b1 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -45,7 +45,8 @@ static int create_compute_queue_nocpsch(struct device_queue_manager *dqm,
 					struct qcm_process_device *qpd);
 
 static int execute_queues_cpsch(struct device_queue_manager *dqm, bool lock);
-static int destroy_queues_cpsch(struct device_queue_manager *dqm, bool lock);
+static int destroy_queues_cpsch(struct device_queue_manager *dqm,
+				bool preempt_static_queues, bool lock);
 
 static int create_sdma_queue_nocpsch(struct device_queue_manager *dqm,
 					struct queue *q,
@@ -775,7 +776,7 @@ static int stop_cpsch(struct device_queue_manager *dqm)
 
 	BUG_ON(!dqm);
 
-	destroy_queues_cpsch(dqm, true);
+	destroy_queues_cpsch(dqm, true, true);
 
 	list_for_each_entry(node, &dqm->queues, list) {
 		pdd = qpd_to_pdd(node->qpd);
@@ -829,7 +830,8 @@ static void destroy_kernel_queue_cpsch(struct device_queue_manager *dqm,
 	pr_debug("kfd: In %s\n", __func__);
 
 	mutex_lock(&dqm->lock);
-	destroy_queues_cpsch(dqm, false);
+	/* here we actually preempt the DIQ */
+	destroy_queues_cpsch(dqm, true, false);
 	list_del(&kq->list);
 	dqm->queue_count--;
 	qpd->is_debug = false;
@@ -935,13 +937,15 @@ static int destroy_sdma_queues(struct device_queue_manager *dqm,
 				unsigned int sdma_engine)
 {
 	return pm_send_unmap_queue(&dqm->packets, KFD_QUEUE_TYPE_SDMA,
-			KFD_PREEMPT_TYPE_FILTER_ALL_QUEUES, 0, false,
+			KFD_PREEMPT_TYPE_FILTER_DYNAMIC_QUEUES, 0, false,
 			sdma_engine);
 }
 
-static int destroy_queues_cpsch(struct device_queue_manager *dqm, bool lock)
+static int destroy_queues_cpsch(struct device_queue_manager *dqm,
+				bool preempt_static_queues, bool lock)
 {
 	int retval;
+	enum kfd_preempt_type_filter preempt_type;
 
 	BUG_ON(!dqm);
 
@@ -960,8 +964,12 @@ static int destroy_queues_cpsch(struct device_queue_manager *dqm, bool lock)
 		destroy_sdma_queues(dqm, 1);
 	}
 
+	preempt_type = preempt_static_queues ?
+			KFD_PREEMPT_TYPE_FILTER_ALL_QUEUES :
+			KFD_PREEMPT_TYPE_FILTER_DYNAMIC_QUEUES;
+
 	retval = pm_send_unmap_queue(&dqm->packets, KFD_QUEUE_TYPE_COMPUTE,
-			KFD_PREEMPT_TYPE_FILTER_ALL_QUEUES, 0, false, 0);
+			preempt_type, 0, false, 0);
 	if (retval != 0)
 		goto out;
 
@@ -989,7 +997,7 @@ static int execute_queues_cpsch(struct device_queue_manager *dqm, bool lock)
 	if (lock)
 		mutex_lock(&dqm->lock);
 
-	retval = destroy_queues_cpsch(dqm, false);
+	retval = destroy_queues_cpsch(dqm, false, false);
 	if (retval != 0) {
 		pr_err("kfd: the cp might be in an unrecoverable state due to an unsuccessful queues preemption");
 		goto out;
@@ -1024,13 +1032,27 @@ static int destroy_queue_cpsch(struct device_queue_manager *dqm,
 {
 	int retval;
 	struct mqd_manager *mqd;
+	bool preempt_all_queues;
 
 	BUG_ON(!dqm || !qpd || !q);
 
+	preempt_all_queues = false;
+
 	retval = 0;
 
 	/* remove queue from list to prevent rescheduling after preemption */
 	mutex_lock(&dqm->lock);
+
+	if (qpd->is_debug) {
+		/*
+		 * error, currently we do not allow to destroy a queue
+		 * of a currently debugged process
+		 */
+		retval = -EBUSY;
+		goto failed_try_destroy_debugged_queue;
+
+	}
+
 	mqd = dqm->ops.get_mqd_manager(dqm,
 			get_mqd_type_from_queue_type(q->properties.type));
 	if (!mqd) {
@@ -1062,6 +1084,8 @@ static int destroy_queue_cpsch(struct device_queue_manager *dqm,
 	return 0;
 
 failed:
+failed_try_destroy_debugged_queue:
+
 	mutex_unlock(&dqm->lock);
 	return retval;
 }