[limmeau]

The MMU is not so cleanly separable from the CPU on x86.

386 has both a segment mechanism and a paging mechanism. The segment mechanism has several luxury features like automatic saving and restoring of task context. It is possible to set up a segment descriptor so that the CPU, when jumping (or faulting) to an address in the segment, will automatically save task state at one address (taken from a register) and restore task state from another address (taken from the descriptor). Ibelieve that's what they use here. Hence, free memory accesses.