I have some cheap wine glasses that I regularly put in the dishwasher. (They are not the really cheap greenish glass but rather thick clear glass.)
White cloudy rings develop over time, and also from where a water drop dried, so I think it is mineral deposits.
I've unsuccessfully tried wiping them with vinegar and I'm also now using "12-in-1" wash tablets that seem to have gradually taken the deposits off my juice glasses (but not the wine glasses.)