amdkfd: introduce new ioctl AMDKFD_IOC_CREATE_PROCESS

This commit implemetns a new ioctl AMDKFD_IOC_CREATE_PROCESS
that creates a new secondary kfd_progress on the FD.

To keep backward compatibility, userspace programs need to invoke
this ioctl explicitly on a FD to create a secondary
kfd_process which replacing its primary kfd_process.

This commit bumps ioctl minor version.

Signed-off-by: Zhu Lingshan <lingshan.zhu@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

3 files changed, 47 insertions, 2 deletions

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 092a2b8aaea1..041237861107 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -3150,6 +3150,48 @@ out:
 	return r;
 }
 
+/* userspace programs need to invoke this ioctl explicitly on a FD to
+ * create a secondary kfd_process which replacing its primary kfd_process
+ */
+static int kfd_ioctl_create_process(struct file *filep, struct kfd_process *p, void *data)
+{
+	struct kfd_process *process;
+	int ret;
+
+	/* Each FD owns only one kfd_process */
+	if (p->context_id != KFD_CONTEXT_ID_PRIMARY)
+		return -EINVAL;
+
+	if (!filep->private_data || !p)
+		return -EINVAL;
+
+	mutex_lock(&kfd_processes_mutex);
+	if (p != filep->private_data) {
+		mutex_unlock(&kfd_processes_mutex);
+		return -EINVAL;
+	}
+
+	process = create_process(current, false);
+	if (IS_ERR(process)) {
+		mutex_unlock(&kfd_processes_mutex);
+		return PTR_ERR(process);
+	}
+
+	filep->private_data = process;
+	mutex_unlock(&kfd_processes_mutex);
+
+	ret = kfd_create_process_sysfs(process);
+	if (ret)
+		pr_warn("Failed to create sysfs entry for the kfd_process");
+
+	/* Each open() increases kref of the primary kfd_process,
+	 * so we need to reduce it here when we create a new secondary process replacing it
+	 */
+	kfd_unref_process(p);
+
+	return 0;
+}
+
 #define AMDKFD_IOCTL_DEF(ioctl, _func, _flags) \
 	[_IOC_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, \
 			    .cmd_drv = 0, .name = #ioctl}
@@ -3268,6 +3310,9 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
 
 	AMDKFD_IOCTL_DEF(AMDKFD_IOC_DBG_TRAP,
 			kfd_ioctl_set_debug_trap, 0),
+
+	AMDKFD_IOCTL_DEF(AMDKFD_IOC_CREATE_PROCESS,
+			kfd_ioctl_create_process, 0),
 };
 
 #define AMDKFD_CORE_IOCTL_COUNT	ARRAY_SIZE(amdkfd_ioctls)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 399f32689678..12f640a9370a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -1053,6 +1053,7 @@ struct amdkfd_ioctl_desc {
 };
 bool kfd_dev_is_large_bar(struct kfd_node *dev);
 
+struct kfd_process *create_process(const struct task_struct *thread, bool primary);
 int kfd_process_create_wq(void);
 void kfd_process_destroy_wq(void);
 void kfd_cleanup_processes(void);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index c52e56aa9316..b4982da9234b 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -68,7 +68,6 @@ static struct workqueue_struct *kfd_restore_wq;
 static struct kfd_process *find_process(const struct task_struct *thread,
 					bool ref);
 static void kfd_process_ref_release(struct kref *ref);
-static struct kfd_process *create_process(const struct task_struct *thread, bool primary);
 
 static void evict_process_worker(struct work_struct *work);
 static void restore_process_worker(struct work_struct *work);
@@ -1582,7 +1581,7 @@ void kfd_process_set_trap_debug_flag(struct qcm_process_device *qpd,
  * On return the kfd_process is fully operational and will be freed when the
  * mm is released
  */
-static struct kfd_process *create_process(const struct task_struct *thread, bool primary)
+struct kfd_process *create_process(const struct task_struct *thread, bool primary)
 {
 	struct kfd_process *process;
 	struct mmu_notifier *mn;