drm/amdkfd: Enable per process SMI event

Process receive event from same process by default. Add a flag to be
able to receive event from all processes, this requires super user
permission.

Event using pid 0 to send the event to all processes, to keep the
default behavior of existing SMI events.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -38,6 +38,8 @@ struct kfd_smi_client {
 	uint64_t events;
 	struct kfd_dev *dev;
 	spinlock_t lock;
+	pid_t pid;
+	bool suser;
 };
 
 #define MAX_KFIFO_SIZE	1024
@@ -151,16 +153,27 @@ static int kfd_smi_ev_release(struct inode *inode, struct file *filep)
 	return 0;
 }
 
-static void add_event_to_kfifo(struct kfd_dev *dev, unsigned int smi_event,
-			      char *event_msg, int len)
+static bool kfd_smi_ev_enabled(pid_t pid, struct kfd_smi_client *client,
+			       unsigned int event)
+{
+	uint64_t all = KFD_SMI_EVENT_MASK_FROM_INDEX(KFD_SMI_EVENT_ALL_PROCESS);
+	uint64_t events = READ_ONCE(client->events);
+
+	if (pid && client->pid != pid && !(client->suser && (events & all)))
+		return false;
+
+	return events & KFD_SMI_EVENT_MASK_FROM_INDEX(event);
+}
+
+static void add_event_to_kfifo(pid_t pid, struct kfd_dev *dev,
+			       unsigned int smi_event, char *event_msg, int len)
 {
 	struct kfd_smi_client *client;
 
 	rcu_read_lock();
 
 	list_for_each_entry_rcu(client, &dev->smi_clients, list) {
-		if (!(READ_ONCE(client->events) &
-				KFD_SMI_EVENT_MASK_FROM_INDEX(smi_event)))
+		if (!kfd_smi_ev_enabled(pid, client, smi_event))
 			continue;
 		spin_lock(&client->lock);
 		if (kfifo_avail(&client->fifo) >= len) {
@@ -176,9 +189,9 @@ static void add_event_to_kfifo(struct kfd_dev *dev, unsigned int smi_event,
 	rcu_read_unlock();
 }
 
-__printf(3, 4)
-static void kfd_smi_event_add(struct kfd_dev *dev, unsigned int event,
-			      char *fmt, ...)
+__printf(4, 5)
+static void kfd_smi_event_add(pid_t pid, struct kfd_dev *dev,
+			      unsigned int event, char *fmt, ...)
 {
 	char fifo_in[KFD_SMI_EVENT_MSG_SIZE];
 	int len;
@@ -193,7 +206,7 @@ static void kfd_smi_event_add(struct kfd_dev *dev, unsigned int event,
 	len += vsnprintf(fifo_in + len, sizeof(fifo_in) - len, fmt, args);
 	va_end(args);
 
-	add_event_to_kfifo(dev, event, fifo_in, len);
+	add_event_to_kfifo(pid, dev, event, fifo_in, len);
 }
 
 void kfd_smi_event_update_gpu_reset(struct kfd_dev *dev, bool post_reset)
@@ -206,13 +219,13 @@ void kfd_smi_event_update_gpu_reset(struct kfd_dev *dev, bool post_reset)
 		event = KFD_SMI_EVENT_GPU_PRE_RESET;
 		++(dev->reset_seq_num);
 	}
-	kfd_smi_event_add(dev, event, "%x\n", dev->reset_seq_num);
+	kfd_smi_event_add(0, dev, event, "%x\n", dev->reset_seq_num);
 }
 
 void kfd_smi_event_update_thermal_throttling(struct kfd_dev *dev,
 					     uint64_t throttle_bitmask)
 {
-	kfd_smi_event_add(dev, KFD_SMI_EVENT_THERMAL_THROTTLE, "%llx:%llx\n",
+	kfd_smi_event_add(0, dev, KFD_SMI_EVENT_THERMAL_THROTTLE, "%llx:%llx\n",
 			  throttle_bitmask,
 			  amdgpu_dpm_get_thermal_throttling_counter(dev->adev));
 }
@@ -227,7 +240,7 @@ void kfd_smi_event_update_vmfault(struct kfd_dev *dev, uint16_t pasid)
 	if (!task_info.pid)
 		return;
 
-	kfd_smi_event_add(dev, KFD_SMI_EVENT_VMFAULT, "%x:%s\n",
+	kfd_smi_event_add(0, dev, KFD_SMI_EVENT_VMFAULT, "%x:%s\n",
 			  task_info.pid, task_info.task_name);
 }
 
@@ -251,6 +264,8 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
 	spin_lock_init(&client->lock);
 	client->events = 0;
 	client->dev = dev;
+	client->pid = current->tgid;
+	client->suser = capable(CAP_SYS_ADMIN);
 
 	spin_lock(&dev->smi_lock);
 	list_add_rcu(&client->list, &dev->smi_clients);