Subin from UAE

I am an Indian residing in UAE and intends to visit the Canton fair held in Guangzhou. I already got a Chinese visa stamped on my passport for arrival in China. I intend to take a flight to Hong Kong and meet one of my supplier there before heading to Guangzhou on the same day. Will I require an additional one to visit Hong Kong or am I entitled for it on arrival?

Also after exiting Hong Kong, can I comeback there after the Canton fair to catch my return flight to Dubai?