diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index ca3845d023..a75e559134 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -63,6 +63,8 @@ struct CPUS390XState {
     uint64_t etoken;       /* etoken */
     uint64_t etoken_extension; /* etoken extension */
 
+    uint64_t diag318_info;
+
     /* Fields up to this point are not cleared by initial CPU reset */
     struct {} start_initial_reset_fields;
 
@@ -118,8 +120,6 @@ struct CPUS390XState {
     uint16_t external_call_addr;
     DECLARE_BITMAP(emergency_signals, S390_MAX_CPUS);
 
-    uint64_t diag318_info;
-
 #if !defined(CONFIG_USER_ONLY)
     uint64_t tlb_fill_tec;   /* translation exception code during tlb_fill */
     int tlb_fill_exc;        /* exception number seen during tlb_fill */
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index 5b1fdb55c4..6acf14d5ec 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -1585,6 +1585,10 @@ void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info)
         env->diag318_info = diag318_info;
         cs->kvm_run->s.regs.diag318 = diag318_info;
         cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_DIAG318;
+        /*
+         * diag 318 info is zeroed during a clear reset and
+         * diag 308 IPL subcodes.
+         */
     }
 }