In a medium saucepan, bring the chicken stock to a boil. Cover and keep hot over low heat. In a large saucepan, heat the olive oil. Add the onion and garlic and cook over moderate heat until softened, about 3 minutes. Add the rice and cook over moderately high heat, stirring, for 2 minutes. Add the white wine and boil, stirring, until almost evaporated. Add enough hot stock to just cover the rice and cook over moderate heat, stirring constantly, until it has been absorbed. Continue adding stock, 1 cup at a time, stirring constantly until it is absorbed and the rice is just tender and very creamy, about 20 minutes.