[PATCH v1 1/2] target/arm: detect 64 bit overflow caused by high cval + voff

[Alex Bennée]

If we don't detect this we will be stuck in a busy loop as we schedule
a timer for before now which will continually trigger gt_recalc_timer
even though we haven't reached the state required to trigger the IRQ.

Bug: https://bugs.launchpad.net/bugs/1859021
Cc: address@hidden
Signed-off-by: Alex Bennée <address@hidden>
---
 target/arm/helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 19a57a17da5..eb17106f7bd 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -2481,6 +2481,9 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
         } else {
             /* Next transition is when we hit cval */
             nexttick = gt->cval + offset;
+            if (nexttick < gt->cval) {
+                nexttick = UINT64_MAX;
+            }
         }
         /* Note that the desired next expiry time might be beyond the
          * signed-64-bit range of a QEMUTimer -- in this case we just
-- 
2.20.1