Re: XenStore as a data transfer path?

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Sat, Jul 21, 2012 at 12:59:31PM -0500, Larry White wrote:
> Hi Konrad,
> 
> >On Tue, Jul 17, 2012 at 11:22:28PM -0500, LarryWhite wrote:
> >I am new to Xen and want to provide simple communication between my DomU
> >and
> >Dom0 environments.  I just need to be able to pass a few bytes of
> >information back and forth between DomU and Dom0 while using some form of
> >event management to know when an update occurs so I can act on it.  At
> >first, it appeared that using XenBus and XenStore might be the right
> >solution for this.  However, after looking over the documentation, it seems
> >that XenBus and XenStore should only be used in a PVM Xen configuration,
> >not
> >a HVM model like mine.  Is this true?  
> 
> >>It can be done in HVM.
> 
> >What would be the best way to accomplish this?  Is there any sample code
> >which demonstrates this for a HVM Xen environment?
> 
> >>libvchan is your best bet.
> 
> Have been looking at libvchan as you suggested.  An additional bit of
> information that I left out on my original post was that I would like to do
> this in a "one to many" environment.  In other words, I want to support data
> transfer from dom0 to a number of different domU's.  Would an approach such
> as libvchan allow for this or would I need a separate process in dom0 for
> each of the different domU channels?  I was really hoping to have a single
> process running in dom0 to manage this. 

You would need seperate rings for each domU. Whether you want to implement this
in a single process or multi-thread the process - or just use one process and
block on the event (signal) to receive an interrupt when data appears - that is up
to you.

> 
> Thanks,
> Larry
> 
>