This is interesting:
South Korean and Chinese defence ministers are to meet in Beijing in February amid rising tension on the Korean peninsula, Seoul has said.
It provided no details of the talks, but the two sides are expected to discuss what Seoul describes as North Korea's hostile acts in recent months.
It is to discuss regional security. Given that China actually seems comfortable with South Korea controlling North Korea's territory should there be a nation collapse north of the DMZ, it could be that the two might touch on how that might take place. You know--for regional security. And in light of how an unnamed third party is threatening said regional security.
While partition may not be necessary to prevent a great power war over who governs what on the peninsula, as a guide of what is allowed closer to China, this post might still offer a guide, in part, since I'm sure China would still like to limit what type of weapons even South Korea deploys north of the DMZ, at least until more trust is established.
Really, from China's point of view, is getting dragged into a war over Pyongyang's fate terribly wise? Or even just watching a war ravage the peninsula, with bad economic consequences that would reach Peking?