use remodel lights, they go in from below.

if possible set up the layout so that you can run the wiring in joist bays.

if this is not possible, you will need to drill across the joists. a long greenlee bit is perfect for the job. cut out for one light and then start drilling to the next light. when the bit gets to teh next cutout, leave it inteh hole, remove it from teh drill, tie the wiring to the end of the bit, and pull it thru. you may need a couple of extentions, depending on how far apart the lights are.

if that is not an option, then be prepared to cut out a lot of rock and redo the ceiling.