event_notifier: enable it to use pipes

This takes the eventfd emulation code from the main loop.  When the
EventNotifier is used for the main loop too, we need this compatibility
code.

Without CONFIG_EVENTFD, event_notifier_get_fd is only usable for the
"read" side of the notifier, for example to set a select() handler.

The return value of event_notifier_set changes to the cleaner 0/-errno.
No caller is actually checking the return value.

Reviewed-by: Anthony Liguori <anthony@codemonkey.ws>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/event_notifier.h b/event_notifier.h
index b283a497ce..88b57af7ce 100644
--- a/event_notifier.h
+++ b/event_notifier.h
@@ -23,7 +23,8 @@ struct EventNotifier {
 #ifdef _WIN32
     HANDLE event;
 #else
-    int fd;
+    int rfd;
+    int wfd;
 #endif
 };