tests/avocado: s390x cpu topology polarization

Polarization is changed on a request from the guest.
Let's verify the polarization is accordingly set by QEMU.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Co-developed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Message-ID: <20231016183925.2384704-17-nsg@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/avocado/s390_topology.py

@@ -41,6 +41,7 @@ class S390CPUTopology(QemuSystemTest):
     The polarization is changed on a request from the guest.
     """
     timeout = 90
+    event_timeout = 10
 
     KERNEL_COMMON_COMMAND_LINE = ('printk.time=0 '
                                   'root=/dev/ram '
@@ -103,6 +104,14 @@ def kernel_init(self):
                          '-initrd', initrd_path,
                          '-append', kernel_command_line)
 
+    def system_init(self):
+        self.log.info("System init")
+        exec_command_and_wait_for_pattern(self,
+                """ mount proc -t proc /proc;
+                    mount sys -t sysfs /sys;
+                    cat /sys/devices/system/cpu/dispatching """,
+                    '0')
+
     def test_single(self):
         """
         This test checks the simplest topology with a single CPU.
@@ -198,3 +207,39 @@ def test_dash_device(self):
         self.check_topology(3, 1, 1, 1, 'high', False)
         self.check_topology(4, 1, 1, 1, 'medium', False)
         self.check_topology(5, 2, 1, 1, 'high', True)
+
+
+    def guest_set_dispatching(self, dispatching):
+        exec_command(self,
+                f'echo {dispatching} > /sys/devices/system/cpu/dispatching')
+        self.vm.event_wait('CPU_POLARIZATION_CHANGE', self.event_timeout)
+        exec_command_and_wait_for_pattern(self,
+                'cat /sys/devices/system/cpu/dispatching', dispatching)
+
+
+    def test_polarization(self):
+        """
+        This test verifies that QEMU modifies the entitlement change after
+        several guest polarization change requests.
+
+        :avocado: tags=arch:s390x
+        :avocado: tags=machine:s390-ccw-virtio
+        """
+        self.kernel_init()
+        self.vm.launch()
+        self.wait_until_booted()
+
+        self.system_init()
+        res = self.vm.qmp('query-s390x-cpu-polarization')
+        self.assertEqual(res['return']['polarization'], 'horizontal')
+        self.check_topology(0, 0, 0, 0, 'medium', False)
+
+        self.guest_set_dispatching('1');
+        res = self.vm.qmp('query-s390x-cpu-polarization')
+        self.assertEqual(res['return']['polarization'], 'vertical')
+        self.check_topology(0, 0, 0, 0, 'medium', False)
+
+        self.guest_set_dispatching('0');
+        res = self.vm.qmp('query-s390x-cpu-polarization')
+        self.assertEqual(res['return']['polarization'], 'horizontal')
+        self.check_topology(0, 0, 0, 0, 'medium', False)