drm/xe: Allow fault injection in exec queue IOCTLs

Use fault injection infrastructure to allow specific functions to
be configured over debugfs for failing during the execution of
xe_exec_queue_create_ioctl(). xe_exec_queue_destroy_ioctl() and
xe_exec_queue_get_property_ioctl() are not considered as there is
no unwinding code to test with fault injection.

This allows more thorough testing from user space by going through
code paths for error handling and unwinding which cannot be reached
by simply injecting errors in IOCTL arguments. This can help
increase code robustness.

The corresponding IGT series is:
https://patchwork.freedesktop.org/series/144138/

Reviewed-by: Sai Teja Pottumuttu <sai.teja.pottumuttu@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250305150659.46276-1-francois.dugast@intel.com
Signed-off-by: Francois Dugast <francois.dugast@intel.com>

drivers/gpu/drm/xe/xe_exec_queue.c

@@ -203,6 +203,7 @@ struct xe_exec_queue *xe_exec_queue_create(struct xe_device *xe, struct xe_vm *v
 	__xe_exec_queue_free(q);
 	return ERR_PTR(err);
 }
+ALLOW_ERROR_INJECTION(xe_exec_queue_create, ERRNO);
 
 struct xe_exec_queue *xe_exec_queue_create_class(struct xe_device *xe, struct xe_gt *gt,
 						 struct xe_vm *vm,

drivers/gpu/drm/xe/xe_hw_engine_group.c

@@ -178,6 +178,7 @@ int xe_hw_engine_group_add_exec_queue(struct xe_hw_engine_group *group, struct x
 	up_write(&group->mode_sem);
 	return err;
 }
+ALLOW_ERROR_INJECTION(xe_hw_engine_group_add_exec_queue, ERRNO);
 
 /**
  * xe_hw_engine_group_del_exec_queue() - Delete an exec queue from a hw engine group

drivers/gpu/drm/xe/xe_vm.c

@@ -270,6 +270,7 @@ int xe_vm_add_compute_exec_queue(struct xe_vm *vm, struct xe_exec_queue *q)
 
 	return err;
 }
+ALLOW_ERROR_INJECTION(xe_vm_add_compute_exec_queue, ERRNO);
 
 /**
  * xe_vm_remove_compute_exec_queue() - Remove compute exec queue from VM