I read the ARMv7 architecture reference manuals. The spec. says LPAE allows 32-bits VA to be translated into 40-bits PA. The 40-bits PA means the width of address bus is 40-bits or greater than 40 bits, is it true? So my first question is what the width of address bus width?
If the width of address bus width is 32-bits, I think the 40-bits PA is useless, because the PA whose address is greater than 4GB can't map to the 32-bits address bus.
If the width of address bus is greater than 40-bits, a new question is coming. We know that VA is 32-bits. If we turn off the MMU, the PA is equal VA. So we can't be allowed to access the PA which is greater than 4GB without MMU opening. I don't know whether my understanding is true or not.