[Qemu-devel] [RFC v2 4/4] Always use eventfd as notifying mechanism

[Alvise Rigo <a.rigo@virtualopensystems.com>]

When eventfd is not configured the method event_notifier_init fallbacks
to the pipe/pipe2 system call, causing an error in VFIO_DEVICE_SET_IRQS
since we pass to the kernel a file descriptor which is not created by
eventfd.

Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
---
 hw/vfio/platform.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index ec6a29e..40109c6 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -324,6 +324,11 @@ static int vfio_enable_intp(VFIODevice *vdev, unsigned int index)
     sysbus_init_irq(sbdev, &intp->qemuirq);
 
     ret = event_notifier_init(&intp->interrupt, 0);
+    if (!ret && (intp->interrupt.rfd != intp->interrupt.wfd)) {
+        /* event_notifier_init created a pipe instead of eventfd */
+        ret = -1;
+    }
+
     if (ret) {
         error_report("vfio: Error: event_notifier_init failed ");
         return ret;
-- 
1.9.1