it can be both, like saying.. "Would you like to come to dinner" which can just mean a small just dinner type thing i guess and "would you like to come for dinner" i think would meanlike a party type dinner.
All of the meals are in the great hall. (in the keep on the first floor) The nobles and the lord and lady sat on the raised dais at the front of the hall. If he visited, the king would also sit at...