Re: [Xen-devel] interdomain event channel using libxc

[Keir Fraser <keir@xxxxxxxxxxxxx>]

On 1/12/06 13:38, "Stephan Creutz" <stephan.creutz@xxxxxxxxxxxxxxxxx> wrote:

> To demonstrate the problem I have two minimal programs (see below). The
> first one is running in Dom0, it allocates a port, print it to the
> console and waits per select for a notification. The second one reads
> the first parameter (which is the remote port), establishes an
> interdomain event channel and notifies the program running in Dom0. When
> I run these programs (the Dom0 program first and the DomU one next)
> nothing happens. The process in Dom0 is blocked in select until the
> timeout occures. No error messages are displayed (which has nothing to
> say, except my own ignorance).
> 
> What I am doing or getting wrong? Can somebody help me, please?

The problem is quite subtle. The libxc function xc_alloc_unbound_port() is
intended to allocate an unbound port in *another* domain. It's used only
during creation of new domains. To allocate a *local* unbound port you need
to define yourself a function along the lines of
xc_evtchn_bind_interdomain() but using IOCTL_EVTCHN_BIND_UNBOUND_PORT rather
than IOCTL_EVTCHN_BIND_INTERDOMAIN.

Probably such a function should be included in libxc, and the existing
xc_alloc_unbound_port() function should be given a clearer name. :-)

 -- Keir


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