WARNING - OLD ARCHIVES

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/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] start of day mem layout

To: "Richard" <judicator3@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] start of day mem layout
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Thu, 17 Mar 2005 21:31:31 -0000
Cc: <ian.pratt@xxxxxxxxxxxx>
Delivery-date: Thu, 17 Mar 2005 22:07:45 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
Thread-index: AcUrNibNsH3nH9dLQHmysum4bZlP1AAAiBZg
Thread-topic: [Xen-devel] start of day mem layout
> I am working on updating the mini-os to work on XEN 2.0. I am
> currently working on the memory management part of mini-os. I am
> trying to undestand the start of day memory layout that the guest
> domain (mini-os) gets from XEN when it 1st boots up. From what I
> undestand, 4 MB of memory are already mapped and virtual memory
> from 0xC000_0000 to 0xC040_0000 (4MB) are accessible. XEN already
> allocates a pgd and ONE page table for this 4MB vritual memory
> mapping.
 
A worthy effort, thanks for doing this.

I can't remember this stuff off-hand, but hopefully someone who's done a
port recently will speak up.

Ian


> I am booting mini-os with 16 MB of memory and these are the
> information I get:
> 
> shared_info                0xc0001000
> pfn_to_mfn                 0xc0010000
> Page Global Directory      0xc0014000
> Page Table                 0xc0015000
> start_info                 0xc0016000
> 
> Also, I think my kernel image contains some symbols such as _text,
> _etext, _edata, _end. 
> 
>  _text                     0xc0000000
> _etext                     0xc0007c04
> _edata                     0xc000d2c0
> _end                       0x819
> 
> I try to draw the virtual mem layout below. Sorry if it does not
> appear correctly because of different fonts.
> 
>                _edata             start_info
>                c000d2c0             c0016000
>   shared_info    |            PGD    |
>    c0001000      |         c0014000  |
>        |         |             |     | 
>   ------------------------------------------
>   |    |    |    |    |        |  |  |
>   |    |    |    |    |        |  |  |
>   |    |    |    |    |        |  |  |
>   ------------------------------------------
>   |         |         |           |
>   c0000000  |       c0010000    c0015000  
>   _text     |      pfn_to_mfn      PT
>             |
>           _etext         
>           c0007c04
> 
> I have a few questions. If someone could give some feedback that
> would be very appreciated.
> 
> I am not sure if those symbols _text, _etext, _edata and _end are
> meaningful or not, but is it correct to have the shared_info in the
> middle of my kernel image between _text and _etext ?
> 
> The default control ring between domain0 and a guest OS is found
> at shared_info + 2048 offset, is that still valid ?
> 
> Is there anything important after the start_info structure ?
> Is address starting at c0016000 + sizeof(start_info) available
> to use ?  
> 
> Also my _end symbol is found at address 0x819, so I don't quite
> udnestand that. Maybe something wrong I am doing in the linking
> process of my kernel image.
> 
> Thanks
> Richard
> 
> 
> -------------------------------------------------------
> 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.
> http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/xen-devel
> 


-------------------------------------------------------
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.
http://ads.osdn.com/?ad_ide95&alloc_id396&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>