I always get my money in with KK preflop. I call. If he has AA...that's why you have a bankroll. There are too many idiots on the interent with crap hands in that spot.

There was nothing fishy with his checkraise with Q7. Just the only hand where I remembered his exact holding. He made some calls in other hands that a good player wouldn't make. But he hadn't made any crazy plays or big overbets.

I called and he won with AA. Dont know if that makes a difference. I think devilmollusk is right: generally this play means aces.
It's a strange play. If he had made a "normal" reraise I could have gotten away cheaper (the flop was QT9). But very few hands will call his raise.