s390x/kvm: execute the first cpu reset on the vcpu thread

As all full cpu resets currently call into the kernel to do initial cpu reset,
let's run this reset (triggered by cpu_s390x_init()) on the proper vcpu thread.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

target-s390x/cpu.c

@@ -175,7 +175,11 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
     S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
 
     qemu_init_vcpu(cs);
+#if !defined(CONFIG_USER_ONLY)
+    run_on_cpu(cs, s390_do_cpu_full_reset, cs);
+#else
     cpu_reset(cs);
+#endif
 
     scc->parent_realize(dev, errp);
 }