Re: [Xen-devel] What is machine address?

[Ronald G. M. <rmi...@la...>]

MA = machine address
PA = physical address
VA = virtual
On Thu, 16 Sep 2004, Steven Hand wrote:

> Physical address = address of a piece of memory used by a guest operating
> system (starting at 0 and going up to the amount of memory you have in 
> that particular virtual machine). 

On real machines, PAs == the real hardware. 

On Xen domains, PAs == not real hardware. 
Xen actually virtualize physical addresses, so although the PA range in an 
OS may be linear and contiguous, the underlying MAs are not. 

At some point I want to fix up Plan 9 to ignore PAs entirely and just VA 
and MA, but that's for later. The concept of a PA has no real meaning 
anyway at this point, so I see no reason to deal with it.

ron