10 hours layover in Shanghai

Hi. I am Malaysian, holding Malaysian passport, flying from Kuala Lumpur to Shanghai for a 10 hours layover before flying to Hiroshima. Then after One week, I will be flying back from Hiroshima to Shanghai for another 10 hours layover before flying back to Kuala Lumpur. Do I need to apply for visa if I travel around Shanghai city during the two 10 hours layover? And can I enjoy the free transit twice? Thank you!