xv6 KERNBASE limitation of process memory

Question

There is a question in the xv6 book which bothers me for a long time, and I wondered if anyone would like to clarify on this

KERNBASE limits the amount of memory a single process can use, which might be irritating on a machine with a full 4 GB of RAM. Would raising KERNBASE allow a process to use more memory?

In my opinion the answer to this question is no, since the whole mechanism around xv6 is designed to work with KERNBASE on a specific address space.

Thanks for any answer.

Answer 1

Well, there is an issue here.

All physical addresses which are supposed to be used are mapped to virtual addresses 0x80000000 and up.

So, if you move KERNBASE upawards, the OS can use less physical memory.