Hey so I know that when the mmu converts a virtual address into a physical address it uses a register called page-table base register which contains the address of the beginning of the page table.
So to convert a virtual address to a physical one you just take this address and add the page number to it to get the address of the physical page address.
But is this process automated with a circuit in the mmu or does the operating system have to take control?
In typical modern computers, this process of translating virtual to physical addresses is done entirely by the MMU hardware. The OS only gets involved if the virtual address turns out to be unmapped or the access is otherwise invalid, in which case the hardware signals a page fault which the OS software must handle.