[PATCH 14/16] xen/events: allow event channel priority to be set

[David Vrabel <david.vrabel@citrix.com>]

From: David Vrabel <dvrabel@cantab.net>

Add xen_irq_set_priority() to set an event channels priority.  This function
will only work with event channel ABIs that support priority (i.e., the
FIFO-based ABI).

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 drivers/xen/events/events.c |   17 +++++++++++++++++
 include/xen/events.h        |    5 +++++
 2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/events/events.c b/drivers/xen/events/events.c
index 3a154d9..5551374 100644
--- a/drivers/xen/events/events.c
+++ b/drivers/xen/events/events.c
@@ -1092,6 +1092,23 @@ void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 }
 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 
+/**
+ * xen_set_irq_priority() - set an event channel priority.
+ * @irq:irq bound to an event channel.
+ * @priority: priority between XEN_IRQ_PRIORITY_MAX and XEN_IRQ_PRIORITY_MIN.
+ */
+int xen_set_irq_priority(unsigned irq, unsigned priority)
+{
+	struct evtchn_set_priority set_priority;
+
+	set_priority.port = evtchn_from_irq(irq);
+	set_priority.priority = priority;
+
+	return HYPERVISOR_event_channel_op(EVTCHNOP_set_priority,
+					   &set_priority);
+}
+EXPORT_SYMBOL_GPL(xen_set_irq_priority);
+
 int evtchn_make_refcounted(unsigned int evtchn)
 {
 	int irq = get_evtchn_to_irq(evtchn);
diff --git a/include/xen/events.h b/include/xen/events.h
index c9ea10e..d265d7e 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -37,6 +37,11 @@ int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
  */
 void unbind_from_irqhandler(unsigned int irq, void *dev_id);
 
+#define XEN_IRQ_PRIORITY_MAX     EVTCHN_FIFO_PRIORITY_MAX
+#define XEN_IRQ_PRIORITY_DEFAULT EVTCHN_FIFO_PRIORITY_DEFAULT
+#define XEN_IRQ_PRIORITY_MIN     EVTCHN_FIFO_PRIORITY_MIN
+int xen_set_irq_priority(unsigned irq, unsigned priority);
+
 /*
  * Allow extra references to event channels exposed to userspace by evtchn
  */
-- 
1.7.2.5