minios: Fix lost events

evtchn_bind_interdomain used to clear any already pending event before
binding a handler, because else the handler may be called before it is
ready. That however leads to missed events, which I had to workaround
for the HVM case.

This changes the semantics of bind_evtchn, and thus of all the
event channel binding functions (bind_virq, evtchn_alloc_unbound,
evtchn_bind_interdomain) into not unmasking the event itself, hence
letting the caller initialize properly before unmasking the port (e.g.
record the port number in an appropriate place).

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/extras/mini-os/arch/x86/time.c b/extras/mini-os/arch/x86/time.c
index c8313705ae..a396dc279f 100644
--- a/extras/mini-os/arch/x86/time.c
+++ b/extras/mini-os/arch/x86/time.c
@@ -222,6 +222,8 @@ static void timer_handler(evtchn_port_t ev, struct pt_regs *regs, void *ign)
 
 void init_time(void)
 {
+    evtchn_port_t port;
     printk("Initialising timer interface\n");
-    bind_virq(VIRQ_TIMER, &timer_handler, NULL);
+    port = bind_virq(VIRQ_TIMER, &timer_handler, NULL);
+    unmask_evtchn(port);
 }