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>

2 files changed, 8 insertions, 5 deletions

diff --git a/extras/mini-os/arch/ia64/time.c b/extras/mini-os/arch/ia64/time.c
index 9fb3157fb6..bbaa6b1864 100644
--- a/extras/mini-os/arch/ia64/time.c
+++ b/extras/mini-os/arch/ia64/time.c
@@ -246,7 +246,7 @@ init_time(void)
 {
 	uint64_t new;
 	efi_time_t tm;
-	int err = 0;
+	evtchn_port_t port = 0;
 
 	printk("Initialising time\n");
 	calculate_frequencies();
@@ -267,11 +267,12 @@ init_time(void)
 	} else
 		printk("efi_get_time() failed\n");
 
-	err = bind_virq(VIRQ_ITC, timer_interrupt, NULL);
-	if (err == -1) {
-		printk("XEN timer request chn bind failed %i\n", err);
+	port = bind_virq(VIRQ_ITC, timer_interrupt, NULL);
+	if (port == -1) {
+		printk("XEN timer request chn bind failed %i\n", port);
 		return;
 	}
+        unmask_evtchn(port);
 	itc_alt = ia64_get_itc();
 	itc_at_boot = itc_alt;
 	new = ia64_get_itc() + itm_val;
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);
 }