I hold a greek passport. Do I need to apply for a VISA to visit Hong Kong, China for 4 days?

I am a citizen of Greece (I hold a greek passport) and I live and work in Montreal, Canada. I need to travel to Hong Kong, China for a presentation to Hong Kong Polytechnique University. I will stay in Hong Kong, China for 4 days. Do I need to apply for a VISA or can I just travel with my passport documentation?