This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


RE: [Xen-devel] PAE support revisited

On Tue, 22 Mar 2005, Ian Pratt wrote:

> There are a few things that need to be sorted to get PAE to work:
>  * cleanup use of 'unsigned long' that exists in some handling of PTEs.
> We've agreed a strategy of doing this with Gerd
>  * change hypercall structs (possibly just switch to using x86_64 mem op
> hypercall layout)
>  * Modify Linux arch xen to using a variable sized hypervisor hole in
> the top of the VA space. Possibly best done by moving fixaddr to the
> bottom end of memory.
>  * adjust hypervisor memory layout to deal with larger variable sized
> frame table.
>  * add 3-level type checking to Xen (this should be easy as it already
> supports 2 and 4 level)
>  * add 3-level support to Linux arch Xen (this should be easy as the
> there are very few modifications to the mm system these days) 
> Once its working, there are a few other features that would be nice:
>  * shadow mode support to run 2 level guests on a 3 level hypervisor
>  * Linux kernel that boot time switches between 2 and 3 level. I'm sure
> the distros would love this on native x86. I believe it can be done with
> low performance cost by using function dispatch patching to switch
> between 2 and 3 level versions of Linux's performance critical functions
> (e.g. the _range functions and fork), and then just using 'if'
> statements in the pte macros used by the less critical functions.  
> It would be great if other people could start tackling some of the items
> on the list.

man, all this work for a dead architecture. Are you sure you can't just 
use k8 and run the apps in compatibility mode? PAE is such a kludge!


SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
Xen-devel mailing list