From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julian Stecklina <der_julian@web.de>
Subject: Event Channels
Date: Fri, 12 Jan 2007 19:33:19 +0100
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Hello,

in an application I develop, event channel semantics seem a bit odd to 
me. Consider the following scenario: A Mini-OS binds an unbound port for
domain 0 and issues a notification every second:

	evtchn_alloc_unbound(0, msg_handler, NULL,
			     &port);

	printk("%u %u %u\n", domid, port);

	while (1) {
		sleep(1000);
		notify_remote_via_evtchn(port);
	}

A Linux program running on Domain 0 calls bind_interdomain using domid
and port to obtain local_port and watches for pending notifications:

	evtchn_port_t local_port = xc_evtchn_bind_interdomain(ev, domid, port);

	while (1) {
		evtchn_port_t port;

		port = xc_evtchn_pending(ev);
		printf("%u\n", port);
		xc_evtchn_unmask(ev, port);
	}

Now what I do not understand is, why the Linux program sees exactly one
notification and then indefinitely blocks. Any help on what I may be 
doing wrong is greatly appreciated. This is with xen-3.0.4-testing.

Regards,
Julian