Re: What is domain creation flow-chart in XEND

[Anthony Liguori <anthony@codemonkey.ws>]

I can answer some of this.  This is what I've been able to figure out.  
It could be wrong.

Nauzad Sadry wrote:

>Hello all
>
>I am a newbie in Python & have been trying to understand the set of
>operations performed by XEND in order to create a new domain. Can
>someone answer the following questions about domain creation
>
>1. The set of Hypercalls requests made by XEND to XEN thru the privcmd driver
>  
>
It's a two step process.  First the raw domain is created, then Linux 
(or something else) is loaded.  For the first part, it's actually quite 
simple.  Xend issues a DOM0_CREATEDOMAIN hypercall.  That will create an 
empty domain with a certain amount of CPUs and visible memory.

The next part is more complicated.  For Linux, it's all pretty much done 
in the xc_linux_build() function (tools/libxc/xc_linux_build.c).  This 
code is straight foreword.

>2. What event channels get created & what entities are involved in
>setting up the event channels.
>  
>
 From what I can tell, Linux always listens on event channel 1.  So, 
Xend just binds a local port to the domains port 1.  After binding, it 
maps a shared memory region and works on a ring queue passing back and 
forth control_msg_t structures.  This is how virtual devices are setup.

I imagine each device gets it's own channel but I do not know for sure.

>3. A control channel is supposed to exist between XEND & the domain.
>If XEND listens to one end of the channel, then what entity in the
>domain listens to the other end
>  
>
The domain's kernel I believe.

>If someone can point me to some document for more details I would appreciate it
>  
>
I posted some documentation to xc.h.  This is where most of this work is 
done.  I don't know of any documentation.  The bulk of all this is done 
in libxc, xu.c (this binding implements a bunch of functionality), and 
x2d2 (this isn't used by Xend but is a bit easier to understand than Xend).

Regards,

>Thanks
>
>Nauzad
>
>
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>



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