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Re: [Xen-devel] Is there example code and/or documentation for developing a Xen back-end/front-end driver pair?

On Mon, Jun 26, 2006 at 03:45:04PM -0700, Randy Thelen wrote:

> Ewan Mellor wrote:
> >Attached are some notes of mine.  They are quite old, but I think  
> >it all is
> >pretty much relevant.
> >
> >Basically, a backend watches /local/domain/0/backend/<deviceClass>  
> >and a
> >frontend watches /local/domain/<domID>/device/<deviceClass>.  When  
> >the tools
> >write into those directories in the store, the drivers get a watch  
> >fired, and
> >check those directories to see the new device details.  The new  
> >internal state
> >is created based on that.
> >
> >If you are using the normal Xenbus code, then you can register your  
> >device
> >driver with the Xenbus layer, and much of this is done for you.
> >
> >The drivers themselves use a simple state machine to handshake  
> >between front
> >and backends.
> >
> >The backends use hotplug / udev events inside domain 0 to trigger  
> >scripts for
> >simple bringup/teardown stuff, like attaching new vifs to bridges or
> >whatever.  The tools watch for a specific node to be written in the  
> >store to
> >indicate that this hotplug phase has succeeded (it's usually the  
> >one that does
> >the final sanity checking and often has to bail out).
> >
> >HTH,
> IHI {It Helps Indeed!}  Thanks.  Could I encourage you to post those  
> on the XenSource Wiki?

I thought someone had already (obviously not).  I've put them on a
XenSplitDrivers page.



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