The Smith machine gets a lot of hate from strength coaches, but it can be an excellent hypertrophy tool for bodybuilders when used correctly. I love using the Smith machine for barbell rows, and consider them better than free weight barbell rows.
These are bad to the bone once you figure out how to do them. You can also set up the "stops" so you can enjoy a dead-stop or rest-pause version.
The main point is to pull the bar into your abs (just a shade above the bellybutton) by driving the elbows up. Don't pull the bar up with the arms – drive with your elbows.
As with any row, keep your back flat and tight and wear a belt. Watch the video, especially the last set in the drop set, and see how my body position is fixed and I'm just driving with my elbows.