target/s390x/cpu_models: Make kvm_s390_apply_cpu_model() return boolean

As error.h suggested, the best practice for callee is to return
something to indicate success / failure.

So make kvm_s390_apply_cpu_model() return boolean and check the
returned boolean in apply_cpu_model() instead of accessing @err.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240425031232.1586401-7-zhao1.liu@intel.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

target/s390x/cpu_models.h

@@ -116,6 +116,6 @@ S390CPUDef const *s390_find_cpu_def(uint16_t type, uint8_t gen, uint8_t ec_ga,
 
 bool kvm_s390_cpu_models_supported(void);
 bool kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp);
-void kvm_s390_apply_cpu_model(const S390CPUModel *model,  Error **errp);
+bool kvm_s390_apply_cpu_model(const S390CPUModel *model,  Error **errp);
 
 #endif /* TARGET_S390X_CPU_MODELS_H */

target/s390x/cpu_models_sysemu.c

@@ -405,8 +405,7 @@ void apply_cpu_model(const S390CPUModel *model, Error **errp)
     }
 
     if (kvm_enabled()) {
-        kvm_s390_apply_cpu_model(model, &err);
+        if (!kvm_s390_apply_cpu_model(model, &err)) {
-        if (err) {
             error_propagate(errp, err);
             return;
         }

target/s390x/kvm/kvm.c

@@ -2543,7 +2543,7 @@ static void kvm_s390_configure_apie(bool interpret)
     }
 }
 
-void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
+bool kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
 {
     struct kvm_s390_vm_cpu_processor prop  = {
         .fac_list = { 0 },
@@ -2560,11 +2560,11 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
         if (kvm_s390_cmma_available()) {
             kvm_s390_enable_cmma();
         }
-        return;
+        return true;
     }
     if (!kvm_s390_cpu_models_supported()) {
         error_setg(errp, "KVM doesn't support CPU models");
-        return;
+        return false;
     }
     prop.cpuid = s390_cpuid_from_cpu_model(model);
     prop.ibc = s390_ibc_from_cpu_model(model);
@@ -2574,19 +2574,19 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
     rc = kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
     if (rc) {
         error_setg(errp, "KVM: Error configuring the CPU model: %d", rc);
-        return;
+        return false;
     }
     /* configure cpu features indicated e.g. via SCLP */
     rc = configure_cpu_feat(model->features);
     if (rc) {
         error_setg(errp, "KVM: Error configuring CPU features: %d", rc);
-        return;
+        return false;
     }
     /* configure cpu subfunctions indicated via query / test bit */
     rc = configure_cpu_subfunc(model->features);
     if (rc) {
         error_setg(errp, "KVM: Error configuring CPU subfunctions: %d", rc);
-        return;
+        return false;
     }
     /* enable CMM via CMMA */
     if (test_bit(S390_FEAT_CMM, model->features)) {
@@ -2601,8 +2601,9 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
     rc = configure_uv_feat_guest(model->features);
     if (rc) {
         error_setg(errp, "KVM: Error configuring CPU UV features %d", rc);
-        return;
+        return false;
     }
+    return true;
 }
 
 void kvm_s390_restart_interrupt(S390CPU *cpu)