s390x: avoid calling kvm_ functions outside of target/s390x/

Let's just introduce an helper.
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170818114353.13455-17-david@redhat.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

hw/s390x/s390-virtio-ccw.c

@@ -144,9 +144,7 @@ static void ccw_init(MachineState *machine)
     /* register hypercalls */
     virtio_ccw_register_hcalls();
 
-    if (kvm_enabled()) {
-        kvm_s390_enable_css_support(s390_cpu_addr2state(0));
-    }
+    s390_enable_css_support(s390_cpu_addr2state(0));
     /*
      * Non mcss-e enabled guests only see the devices from the default
      * css, which is determined by the value of the squash_mcss property.

target/s390x/cpu.c

@@ -471,6 +471,13 @@ bool s390_get_squash_mcss(void)
 
     return false;
 }
+
+void s390_enable_css_support(S390CPU *cpu)
+{
+    if (kvm_enabled()) {
+        kvm_s390_enable_css_support(cpu);
+    }
+}
 #endif
 
 static gchar *s390_gdb_arch_name(CPUState *cs)

target/s390x/cpu.h

@@ -404,6 +404,7 @@ int cpu_s390x_signal_handler(int host_signum, void *pinfo,
 
 #ifndef CONFIG_USER_ONLY
 
+void s390_enable_css_support(S390CPU *cpu);
 int s390_virtio_hypercall(CPUS390XState *env);
 
 #ifdef CONFIG_KVM