Preheat oven to 425 degrees F. Pat tenderloin dry, and season on all sides with ½ teaspoon of the pepper and ¼ teaspoon of the salt. Heat olive oil in a large ovenproof nonstick skillet over medium-high. Add pork, and cook 3 minutes on 1 side. Turn pork, and cook until both sides are browned, about 2 more minutes.
Move tenderloin to 1 side of skillet, and add shallots and garlic. Reduce heat to medium; cook, stirring shallots and garlic often, until shallots soften, 3 to 4 minutes. Add tomatoes and raisins, and cook, stirring often, until tomatoes begin to soften, about 3 minutes. Add ¾ teaspoon rosemary and remaining ½ teaspoon pepper and ¼ teaspoon salt; stir to blend tomato mixture. Place skillet in oven, and cook until a thermometer inserted in pork registers 145 degrees F, 10 to 12 minutes.
Remove pork from skillet, and place on a cutting board; let meat rest 6 to 8 minutes before slicing. Stir vinegar into tomato mixture in skillet. Serve slices of pork with tomato confit, and sprinkle servings with remaining ¾ teaspoon chopped rosemary.
