Studying the properties of the liquid phase of minerals at high pressure is important to understand the structure and evolution of deep magma oceans, as well as guiding high pressure experiments that reach the conditions in the interiors of rocky planets. We use density functional theory molecular dynamics (DFT-MD) and path integral Monte Carlo (PIMC) simulations to generate a consistent equation of state (EOS) for liquid MgSiO3 that spans across a wide range of temperatures and pressures. We study its thermodynamic properties, such as the heat capacity, and characterize the atomic structure of the liquid. From our simulations, we are able to determine the onset of ionization of the inner electronic shells and relate the thermodynamic properties to the electronic structure. Finally, in order to guide future ramp and shock compression experiments, we derive isentropic temperature-pressure profiles and calculate the shock Hugoniot curve, which is in good agreement with existing experimental data.