Re: process max virtual memory limit in amd64?

[Marc Bevand <bevand_m@epita.fr>]

Anders Fugmann wrote:
> Gabriel Ebner wrote:
>
> > On Fri, Jun 25, 2004 at 10:46:05AM +0300, Georgi Guninski wrote:
> > gebner@schnecke2 ~ [0] $ grep 'address sizes' /proc/cpuinfo
> > address sizes   : 40 bits physical, 48 bits virtual
>
> Does anyone know why there is a limitation of 48 bits on the virtual 
> address space, and if it is technically possible to have a 64 bit 
> address space on the AMD64 architecture?

AMD64 manual says:

``Currently, the AMD64 architecture defines a mechanism for
translating 48-bit virtual addresses to 52-bit physical addresses.
The mechanism used to translate a full 64-bit virtual address is
reserved and will be described in a future AMD64 architectural
specification.''

The 48-bit limit is due to the 4-level paging mechanisme defined
by AMD64.

--
Marc Bevand                          http://www.epita.fr/~bevand_m
Computer Science School EPITA - System, Network and Security Dept.