Index: sys/xen/xen_intr.c
===================================================================
--- sys/xen/xen_intr.c
+++ sys/xen/xen_intr.c
@@ -120,9 +120,10 @@
 
 DPCPU_DECLARE(struct vcpu_info *, vcpu_info);
 
-#define	XEN_INVALID_EVTCHN	0 /* Invalid event channel */
+#define	INVALID_PORT		~0 /* Invalid xi_port value */
 
-#define	is_valid_evtchn(x)	((x) != XEN_INVALID_EVTCHN)
+#define	is_valid_evtchn(x)	((uint64_t)(x) - 1 < NR_EVENT_CHANNELS)
+#define	isrc_port_valid(i)	((uint64_t)((i)->xi_port) < NR_EVENT_CHANNELS)
 
 struct xen_arch_isrc {
 	struct intsrc		xai_intsrc;	/* @TOP -> *xen_arch_isrc */
@@ -232,7 +233,7 @@
  *        event channel globally, use evtchn_mask().
  */
 static inline void
-evtchn_cpu_mask_port(u_int cpu, evtchn_port_t port)
+xen_intr_cpu_mask_port(u_int cpu, evtchn_port_t port)
 {
 	struct xen_intr_pcpu_data *pcpu;
 
@@ -254,7 +255,7 @@
  *        also be globally enabled.  See evtchn_unmask().
  */
 static inline void
-evtchn_cpu_unmask_port(u_int cpu, evtchn_port_t port)
+xen_intr_cpu_unmask_port(u_int cpu, evtchn_port_t port)
 {
 	struct xen_intr_pcpu_data *pcpu;
 
@@ -337,7 +338,7 @@
 		return (isrc);
 	}
 
-	if (xen_intr_auto_vector_count > NR_EVENT_CHANNELS) {
+	if (xen_intr_auto_vector_count >= NR_EVENT_CHANNELS) {
 		if (!warned) {
 			warned = 1;
 			printf("%s: Event channels exhausted.\n", __func__);
@@ -376,15 +377,15 @@
 	mtx_lock(&xen_intr_isrc_lock);
 	KASSERT(isrc->xi_arch.xai_intsrc.is_handlers == 0,
 	    ("Release called, but xenisrc still in use"));
-	evtchn_mask_port(isrc->xi_port);
-	evtchn_clear_port(isrc->xi_port);
+	evtchn_mask_port(isrc->xi_port + 1);
+	evtchn_clear_port(isrc->xi_port + 1);
 
 	/* Rebind port to CPU 0. */
-	evtchn_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
-	evtchn_cpu_unmask_port(0, isrc->xi_port);
+	xen_intr_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
+	xen_intr_cpu_unmask_port(0, isrc->xi_port);
 
-	if (isrc->xi_close != 0 && is_valid_evtchn(isrc->xi_port)) {
-		struct evtchn_close close = { .port = isrc->xi_port };
+	if (isrc->xi_close != 0 && isrc_port_valid(isrc)) {
+		struct evtchn_close close = { .port = isrc->xi_port + 1 };
 		if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close))
 			panic("EVTCHNOP_close failed");
 	}
@@ -394,7 +395,7 @@
 	mtx_unlock(&xen_intr_isrc_lock);
 
 	isrc->xi_cpu = 0;
-	isrc->xi_port = 0;
+	isrc->xi_port = INVALID_PORT;
 	isrc->xi_cookie = NULL;
 	mtx_lock(&xen_intr_x86_lock);
 	isrc->xi_type = EVTCHN_TYPE_UNBOUND;
@@ -443,8 +444,8 @@
 	if (isrc == NULL)
 		return (ENOSPC);
 	mtx_lock(&xen_intr_isrc_lock);
-	isrc->xi_port = local_port;
-	xen_intr_port_to_isrc[local_port] = isrc;
+	isrc->xi_port = local_port - 1;
+	xen_intr_port_to_isrc[isrc->xi_port] = isrc;
 	refcount_init(&isrc->xi_refcount, 1);
 	mtx_unlock(&xen_intr_isrc_lock);
 
@@ -715,7 +716,7 @@
 	if (error != 0)
 		panic("unable to rebind xen IPI: %d", error);
 
-	isrc->xi_port = bind_ipi.port;
+	isrc->xi_port = bind_ipi.port - 1;
 #else
 	panic("Resume IPI event channel on UP");
 #endif
@@ -735,7 +736,7 @@
 	if (error != 0)
 		panic("unable to rebind xen VIRQ#%d: %d", isrc->xi_virq, error);
 
-	isrc->xi_port = bind_virq.port;
+	isrc->xi_port = bind_virq.port - 1;
 }
 
 static void
@@ -744,7 +745,7 @@
 	int cpu = isrc->xi_cpu;
 	int error;
 
-	isrc->xi_port = 0;
+	isrc->xi_port = INVALID_PORT;
 	switch (isrc->xi_type) {
 	case EVTCHN_TYPE_IPI:
 		xen_rebind_ipi(isrc);
@@ -799,35 +800,35 @@
 	/* Clear existing port mappings */
 	for (isrc_idx = 0; isrc_idx < NR_EVENT_CHANNELS; ++isrc_idx)
 		if (xen_intr_port_to_isrc[isrc_idx] != NULL)
-			xen_intr_port_to_isrc[isrc_idx]->xi_port = ~0;
+			xen_intr_port_to_isrc[isrc_idx]->xi_port = INVALID_PORT;
 
 	/* Remap in-use isrcs, using xen_intr_port_to_isrc as listing */
 	for (isrc_idx = 0; isrc_idx < NR_EVENT_CHANNELS; ++isrc_idx) {
 		struct xenisrc *cur = xen_intr_port_to_isrc[isrc_idx];
 
 		/* empty or entry already taken care of */
-		if (cur == NULL || cur->xi_port != ~0)
+		if (cur == NULL || isrc_port_valid(cur))
 			continue;
 
 		xen_intr_port_to_isrc[isrc_idx] = NULL;
 
 		do {
 			struct xenisrc *next;
-			KASSERT(cur->xi_port == ~0,
+			KASSERT(!isrc_port_valid(cur),
 				("%s(): Multiple channels on single intr?",
 				__func__));
 
 			xen_intr_rebind_isrc(cur);
 
 			/* invalid entry left behind? */
-			if (!is_valid_evtchn(cur->xi_port))
+			if (!isrc_port_valid(cur))
 				break;
 
 			next = xen_intr_port_to_isrc[cur->xi_port];
 
 			xen_intr_port_to_isrc[cur->xi_port] = cur;
 
-			evtchn_unmask_port(cur->xi_port);
+			evtchn_unmask_port(cur->xi_port + 1);
 
 			cur = next;
 		} while (cur != NULL);
@@ -848,7 +849,7 @@
 {
 	struct xenisrc *isrc = (struct xenisrc *)base_isrc;
 
-	evtchn_mask_port(isrc->xi_port);
+	evtchn_mask_port(isrc->xi_port + 1);
 }
 
 /**
@@ -927,7 +928,7 @@
 
 	mtx_lock(&xen_intr_isrc_lock);
 	isrc = (struct xenisrc *)base_isrc;
-	if (!is_valid_evtchn(isrc->xi_port)) {
+	if (!isrc_port_valid(isrc)) {
 		mtx_unlock(&xen_intr_isrc_lock);
 		return (EINVAL);
 	}
@@ -936,7 +937,7 @@
 	 * Mask the event channel while binding it to prevent interrupt
 	 * delivery with an inconsistent state in isrc->xi_cpu.
 	 */
-	masked = evtchn_test_and_set_mask(isrc->xi_port);
+	masked = evtchn_test_and_set_mask(isrc->xi_port + 1);
 	if ((isrc->xi_type == EVTCHN_TYPE_VIRQ) ||
 		(isrc->xi_type == EVTCHN_TYPE_IPI)) {
 		/*
@@ -944,28 +945,28 @@
 		 * the Hypervisor at evtchn_bind_virq time, so
 		 * all we need to do is update the per-CPU masks.
 		 */
-		evtchn_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
+		xen_intr_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
 		isrc->xi_cpu = to_cpu;
-		evtchn_cpu_unmask_port(isrc->xi_cpu, isrc->xi_port);
+		xen_intr_cpu_unmask_port(isrc->xi_cpu, isrc->xi_port);
 		goto out;
 	}
 
-	bind_vcpu.port = isrc->xi_port;
+	bind_vcpu.port = isrc->xi_port + 1;
 	bind_vcpu.vcpu = vcpu_id;
 
 	error = HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu);
 	if (isrc->xi_cpu != to_cpu) {
 		if (error == 0) {
 			/* Commit to new binding by removing the old one. */
-			evtchn_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
+			xen_intr_cpu_mask_port(isrc->xi_cpu, isrc->xi_port);
 			isrc->xi_cpu = to_cpu;
-			evtchn_cpu_unmask_port(isrc->xi_cpu, isrc->xi_port);
+			xen_intr_cpu_unmask_port(isrc->xi_cpu, isrc->xi_port);
 		}
 	}
 
 out:
 	if (masked == 0)
-		evtchn_unmask_port(isrc->xi_port);
+		evtchn_unmask_port(isrc->xi_port + 1);
 	mtx_unlock(&xen_intr_isrc_lock);
 	return (0);
 #else
@@ -1012,7 +1013,7 @@
 	isrc = (struct xenisrc *)base_isrc;
 
 	if (isrc->xi_masked == 0)
-		evtchn_unmask_port(isrc->xi_port);
+		evtchn_unmask_port(isrc->xi_port + 1);
 }
 
 /*
@@ -1035,7 +1036,7 @@
 {
 	struct xenisrc *isrc = (struct xenisrc *)base_isrc;
 
-	evtchn_unmask_port(isrc->xi_port);
+	evtchn_unmask_port(isrc->xi_port + 1);
 }
 
 /*--------------------------- Public Functions -------------------------------*/
@@ -1303,7 +1304,7 @@
 		KASSERT(isrc->xi_type == EVTCHN_TYPE_PORT ||
 			isrc->xi_type == EVTCHN_TYPE_IPI,
 			("evtchn_signal on something other than a local port"));
-		struct evtchn_send send = { .port = isrc->xi_port };
+		struct evtchn_send send = { .port = isrc->xi_port + 1 };
 		(void)HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
 	}
 }
@@ -1317,7 +1318,7 @@
 	if (isrc == NULL)
 		return (0);
 
-	return (isrc->xi_port);
+	return (isrc->xi_port + 1);
 }
 
 int
@@ -1345,7 +1346,7 @@
 xen_intr_get_evtchn_from_port(evtchn_port_t port, xen_intr_handle_t *handlep)
 {
 
-	if (!is_valid_evtchn(port) || port >= NR_EVENT_CHANNELS)
+	if (!is_valid_evtchn(port))
 		return (EINVAL);
 
 	if (handlep == NULL) {
@@ -1391,7 +1392,7 @@
 	int i;
 
 	db_printf("Port %d Type: %s\n",
-	    isrc->xi_port, xen_intr_print_type(isrc->xi_type));
+	    isrc->xi_port + 1, xen_intr_print_type(isrc->xi_type));
 	if (isrc->xi_type == EVTCHN_TYPE_VIRQ)
 		db_printf("\tVirq: %d\n", isrc->xi_virq);