This study will evaluate the safety, tolerability, and effectiveness of a combination of drugs to treat HCV in adults who are coinfected with HIV and HCV. The three drugs are paritaprevir/ritonavir/ombitasvir (PTV/r/OBT), dasabuvir (DSV), and ribavirin (RBV). RBV will be given to participants with HCV genotype 1a only; participants with HCV genotype 1b will not receive RBV.