So I know there are equations that give you the total energy in the Universe(Friedman).
So about if we we to simulate every single interaction from neurons to physical forces, strong and weak, gravity, electromagnetic, every single interaction between bosons, quarks, electrons, neutrons, atoms, molecules, etc. Basically everything with regard to the knowledge that we currently have.
For example in the wiki page for mind uploading, there are estimates that to computationally model the neurons for one person using a 'Stochastic behavior of single molecules' algorithm will take approx, 10E43(CPU FLOPS) and 10E14(Memory) and it wont be till about the year 2111 till his can be done, now that is for the neurons of one person, multiply that by all the billions of people etc.. Then take into account everything else, absolutely everything that can be computationally modeled by an equation.
Yes it would be quite some amount of processing power, is there anyway to approximate how much we would need?