The above sentence in passive voice will be- What is being done by you?
In the given sentence you is the subject where the subject acts upon the verb doing thus it is active. When we convert the given sentence into passive voice, the subject you becomes the receiver of the verb’s action. Because of such conversion, the form of the sentence as well as the form of the verb changes, the verb doing becomes being done. So we get the sentence “What is being done by you”. Since the subject you no longer acts upon the verb thus, it becomes passive.
What are you doing?
Please that sentence change into passive voice