Validy period of passport to visit Hong Kong

Hello, I'm from Russia and I'm working in Korea. I know that for a short stay in Hong Kong I don't need a visa, so I would like to visit Honk Kong for a week-end. But my current passport is valid until the end of October and I'm not sure if I can visit Hong Kong now. Do you know what is the validity period for the passport to visit Hong Kong? Should it be valid for 180 days at the day of entrance, or 90 days, or other amount of days?