[Xen-devel] [PATCH v3 4/6] timers: the rearm function should be able to handle delta = INT64_MAX

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Fix win32_rearm_timer and mm_rearm_timer: they should be able to handle
INT64_MAX as a delta parameter without overflowing.
Also, the next deadline in ms should be calculated rounding down rather
than up (see unix_rearm_timer and dynticks_rearm_timer).

Finally ChangeTimerQueueTimer takes an unsigned long and timeSetEvent
takes an unsigned int as delta, so cast the ms delta to the appropriate
unsigned integer.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 qemu-timer.c |   18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/qemu-timer.c b/qemu-timer.c
index cd026c6..a9ba0eb 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -725,13 +725,17 @@ static void mm_stop_timer(struct qemu_alarm_timer *t)
 
 static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)
 {
-    int nearest_delta_ms = (delta + 999999) / 1000000;
+    int64_t nearest_delta_ms = delta / 1000000;
     if (nearest_delta_ms < 1) {
         nearest_delta_ms = 1;
     }
+    /* UINT_MAX can be 32 bit */
+    if (nearest_delta_ms > UINT_MAX) {
+        nearest_delta_ms = UINT_MAX;
+    }
 
     timeKillEvent(mm_timer);
-    mm_timer = timeSetEvent(nearest_delta_ms,
+    mm_timer = timeSetEvent((unsigned int) nearest_delta_ms,
                             mm_period,
                             mm_alarm_handler,
                             (DWORD_PTR)t,
@@ -786,16 +790,20 @@ static void win32_rearm_timer(struct qemu_alarm_timer *t,
                               int64_t nearest_delta_ns)
 {
     HANDLE hTimer = t->timer;
-    int nearest_delta_ms;
+    int64_t nearest_delta_ms;
     BOOLEAN success;
 
-    nearest_delta_ms = (nearest_delta_ns + 999999) / 1000000;
+    nearest_delta_ms = nearest_delta_ns / 1000000;
     if (nearest_delta_ms < 1) {
         nearest_delta_ms = 1;
     }
+    /* ULONG_MAX can be 32 bit */
+    if (nearest_delta_ms > ULONG_MAX) {
+        nearest_delta_ms = ULONG_MAX;
+    }
     success = ChangeTimerQueueTimer(NULL,
                                     hTimer,
-                                    nearest_delta_ms,
+                                    (unsigned long) nearest_delta_ms,
                                     3600000);
 
     if (!success) {
-- 
1.7.2.5


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