libvirt:Add a driver API to inject an NMI

This patch adds a new driver API to inject an NMI to an instance.
This API is implemented by libvirt driver.

NMI (Non-maskable Interruption) is used to trigger a special function such as
the kernel crash dump mechanism.

DocImpact

Change-Id: Iaf63352139c466430d3304a87a66398133541fac
Implements: blueprint inject-nmi

nova/tests/unit/virt/libvirt/fakelibvirt.py

@@ -751,6 +751,9 @@ class Domain(object):
     def jobStats(self, flags=0):
         return {}
 
+    def injectNMI(self, flags=0):
+        return 0
+
 
 class DomainSnapshot(object):
     def __init__(self, name, domain):

nova/tests/unit/virt/test_virt_drivers.py

@@ -365,6 +365,11 @@ class _VirtDriverTestCase(_FakeDriverBackendTestCase):
         self.connection.power_off(instance_ref)
         self.connection.power_on(self.ctxt, instance_ref, network_info, None)
 
+    @catch_notimplementederror
+    def test_inject_nmi(self):
+        instance_ref, network_info = self._get_running_instance()
+        self.connection.inject_nmi(instance_ref)
+
     @catch_notimplementederror
     def test_soft_delete(self):
         instance_ref, network_info = self._get_running_instance(obj=True)

nova/virt/driver.py

@@ -673,6 +673,13 @@ class ComputeDriver(object):
         """
         raise NotImplementedError()
 
+    def inject_nmi(self, instance):
+        """Inject an NMI to the specified instance.
+
+        :param instance: nova objects.instance.Instance
+        """
+        raise NotImplementedError()
+
     def soft_delete(self, instance):
         """Soft delete the specified instance.
 

nova/virt/fake.py

@@ -243,6 +243,9 @@ class FakeDriver(driver.ComputeDriver):
                  block_device_info=None):
         pass
 
+    def inject_nmi(self, instance):
+        pass
+
     def soft_delete(self, instance):
         pass
 

nova/virt/libvirt/driver.py

@@ -2233,6 +2233,20 @@ class LibvirtDriver(driver.ComputeDriver):
         # and available before we attempt to start the instance.
         self._hard_reboot(context, instance, network_info, block_device_info)
 
+    def inject_nmi(self, instance):
+
+        """Inject an NMI to the specified instance."""
+        try:
+            self._host.get_guest(instance).inject_nmi()
+        except libvirt.libvirtError as ex:
+            error_code = ex.get_error_code()
+            msg = (_('Error from libvirt while injecting an NMI to '
+                     '%(instance_uuid)s: '
+                     '[Error Code %(error_code)s] %(ex)s')
+                   % {'instance_uuid': instance.uuid,
+                      'error_code': error_code, 'ex': ex})
+            raise exception.NovaException(msg)
+
     def suspend(self, context, instance):
         """Suspend the specified instance."""
         guest = self._host.get_guest(instance)

nova/virt/libvirt/guest.py

@@ -114,6 +114,10 @@ class Guest(object):
         """Stops a running guest."""
         self._domain.destroy()
 
+    def inject_nmi(self):
+        """Injects an NMI to a guest."""
+        self._domain.injectNMI()
+
     def resume(self):
         """Resumes a suspended guest."""
         self._domain.resume()