On 14/10/2025 18.05, Ilya Leoshkevich wrote:
Suppose TOD clock value is 0x1111111111111111 and clock-comparator
value is 0, in which case clock-comparator interruption should occur
immediately.
With the current code, tod2time(env->ckc - td->base.low) ends up being
a very large number, so this interruption never happens.
Fix by firing the timer immediately if env->ckc < td->base.low.
Signed-off-by: Ilya Leoshkevich <[email protected]>
---
target/s390x/tcg/misc_helper.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/target/s390x/tcg/misc_helper.c b/target/s390x/tcg/misc_helper.c
index 6d9d601d29a..afcf7688eda 100644
--- a/target/s390x/tcg/misc_helper.c
+++ b/target/s390x/tcg/misc_helper.c
@@ -199,11 +199,15 @@ static void update_ckc_timer(CPUS390XState *env)
return;
}
- /* difference between origins */
- time = env->ckc - td->base.low;
+ if (env->ckc < td->base.low) {
+ time = 0;
+ } else {
+ /* difference between origins */
+ time = env->ckc - td->base.low;
- /* nanoseconds */
- time = tod2time(time);
+ /* nanoseconds */
+ time = tod2time(time);
+ }
timer_mod(env->tod_timer, time);
}
Yes, this looks right.
Reviewed-by: Thomas Huth <[email protected]>
