1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 07e56e5a5d2d..239b011ef56f 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -36,6 +36,7 @@
 #include <asm/idle.h>
 #include <asm/io_apic.h>
 #include <asm/sync_bitops.h>
+#include <asm/xen/pci.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
 
@@ -75,7 +76,8 @@ enum xen_irq_type {
  * event channel - irq->event channel mapping
  * cpu - cpu this event channel is bound to
  * index - type-specific information:
- *    PIRQ - vector, with MSB being "needs EIO"
+ *    PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
+ *           guest, or GSI (real passthrough IRQ) of the device.
  *    VIRQ - virq number
  *    IPI - IPI vector
  *    EVTCHN -