Re: Multiple priviliged domains

[Jacob Gorm Hansen <jacobg@diku.dk>]

Mark Williamson wrote:
l.
> 
> Obviously, dom0 will need control of some physical devices  inorder to have 
> something to boot from (unless  ofcourse you use a *really big* initrd :-) ).
> 

hi,

In my setup, you do not need a very large initrd to do this. 
Essentially, the only thing running in dom0 is a simple ICMP/ping 
server. You send a specially formatted and signed ping payload to dom0, 
and in response to that it fires up a new VM with a UIP TCP/IP stack 
inside.  You then connect to that TCP/IP stack, and self-migrate or 
(eventually, not implemented yet) bootstrap directly into the 
unprivileged guest. Dom0 does not need to have a TCP/IP stack, and at 
present the ping server main loop is only 50 lines of code.

With pre-NGIO version of Xen 1.3 that I am currently using, all you need 
in your dom0-initrd is the ping server and an ELF image from which to 
create UIP guest VMs. I am hoping that in the future the parts of xend 
that have to do with setting up network interfaces to domains will split 
out into a small C executable, as that would allow me to provide similar 
functionality for Xen 2.0 or 2.1.

Source and binaries are available from
http://www.diku.dk/~jacobg/self-migration/

Jacob

PS: I do apologize to the long-time subscribers who are fed with me 
spamming this list with ads for self-migration stuff every time a new 
user who could find this relevant shows up on the list. Perhaps I can 
convince the Xen webpage maintainers to link to my stuff as a related 
project?


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