Xen devel - Feb 2007 - frame_table initialisation

It is unclear for me how variable frame_table is initialised:

1. According to function __start_xen:
Variable frame_table is initialised by __start_xen -> init_frametable.

but

2. some lines before in __start_xen, this variable is referenced by 
function map_pages_to_xen -> virt_to_xen_l2 -> alloc_xen_pagetable -> 
mfn_to_page.
What should the value of frame_table be there?

Do I miss some pre-initialisation(s)?

Armand


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On 26/2/07 14:45, "PUCCETTI Armand" <armand.puccetti@cea.fr>
wrote:
> 2. some lines before in __start_xen, this variable is referenced by
> function map_pages_to_xen -> virt_to_xen_l2 -> alloc_xen_pagetable
->
> mfn_to_page.
> What should the value of frame_table be there?
> 
> Do I miss some pre-initialisation(s)?
The fact that frame_table is not initialised here (and hence will be NULL)
doesn''t actually matter, since the result of mfn_to_page() is only
actually
used as a value to page_to_mfn(). And page_to_mfn(mfn_to_page(m))==m for any
(constant) value of frame_table.

This code could be clearer I''ll admit. It probably makes sense for
alloc_xen_pagetable to return an MFN rather than a page_info pointer.

 -- Keir


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel