On 16/10/2025 14.07, Ilya Leoshkevich wrote:
After reset, CKC value is set to 0, so if clock-comparator interrupts
are enabled, one should occur very shortly thereafter.

Currently the code that loads the respective control register does not
set tod_timer, so this does not happen.

Fix by adding a tcg_s390_tod_updated() call to LCTL and LCTLG.

(I just realized that I mixed up store and load in my previous mail to this patch in v2, sorry for the confusion)

Cc: [email protected]
Suggested-by: Thomas Huth <[email protected]>
Signed-off-by: Ilya Leoshkevich <[email protected]>
---
  target/s390x/tcg/mem_helper.c | 11 ++++++++++-
  1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
index f1acb1618f7..24675fc818d 100644
--- a/target/s390x/tcg/mem_helper.c
+++ b/target/s390x/tcg/mem_helper.c
@@ -1959,6 +1959,10 @@ void HELPER(lctlg)(CPUS390XState *env, uint32_t r1, 
uint64_t a2, uint32_t r3)
          if (env->cregs[i] != val && i >= 9 && i <= 11) {
              PERchanged = true;
          }
+        if (i == 0 && !(env->cregs[i] & CR0_CKC_SC) && (val & CR0_CKC_SC)) {
+            BQL_LOCK_GUARD();
+            tcg_s390_tod_updated(env_cpu(env), RUN_ON_CPU_NULL);
+        }
          env->cregs[i] = val;
          HELPER_LOG("load ctl %d from 0x%" PRIx64 " == 0x%" PRIx64 "\n",
                     i, src, val);
@@ -1989,10 +1993,15 @@ void HELPER(lctl)(CPUS390XState *env, uint32_t r1, 
uint64_t a2, uint32_t r3)
for (i = r1;; i = (i + 1) % 16) {
          uint32_t val = cpu_ldl_data_ra(env, src, ra);
+        uint64_t val64 = deposit64(env->cregs[i], 0, 32, val);
          if ((uint32_t)env->cregs[i] != val && i >= 9 && i <= 11) {
              PERchanged = true;
          }
-        env->cregs[i] = deposit64(env->cregs[i], 0, 32, val);
+        if (i == 0 && !(env->cregs[i] & CR0_CKC_SC) && (val64 & CR0_CKC_SC)) {
+            BQL_LOCK_GUARD();
+            tcg_s390_tod_updated(env_cpu(env), RUN_ON_CPU_NULL);
+        }
+        env->cregs[i] = val64;

That looks nicer to me, indeed, thanks!

Reviewed-by: Thomas Huth <[email protected]>


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