Why Virtual Machine fails to start with error "qemu-kvm: CPU feature arat not found" ?

Issue

• Virtual Machines on KVM platform fails to start due cpu flag 'arat' error .
• libvirtd fails to start vm due to 'CPU feature arat not found' after upgrade .

libvirtd.log
2016-11-05 15:53:07.756+0000: 35436: debug : qemuMonitorIO:743 : Error on monitor internal error: qemu unexpectedly closed the monitor: 
(process:36773): GLib-WARNING **: gmem.c:482: custom memory allocation vtable not supported
2016-11-05T15:53:07.752913Z qemu-kvm: CPU feature arat not found

• Compute nodes are not able to start instances after upgrade of libvirtd package .

nova-compute.log
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [req-033d53dd-cb07-414d-8fa8-eac6af441bd7 84d8ddd61564def54a9bce15d9165641931ca976e16508f70fcb55a3f5563d9d 3732cae81595407c92e3ed1683e1c5c6 - - -] [instan
ce: b2053da9-a7ca-4a90-9e7a-1efd07ee547e] Instance failed to spawn
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e] Traceback (most recent call last):
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 2180, in _build_resources
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     yield resources
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 2033, in _build_and_run_instance
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     block_device_info=block_device_info)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2596, in spawn
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     block_device_info=block_device_info)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 4719, in _create_domain_and_n
etwork
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     xml, pause=pause, power_on=power_on)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 4649, in _create_domain
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     guest.launch(pause=pause)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/guest.py", line 142, in launch
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     self._encoded_xml, errors='ignore')
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 204, in __exit__
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     six.reraise(self.type_, self.value, self.tb)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/guest.py", line 137, in launch
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     return self._domain.createWithFlags(flags)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 183, in doit
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     result = proxy_call(self._autowrap, f, *args, **kwargs)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 141, in proxy_call
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     rv = execute(f, *args, **kwargs)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 122, in execute
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     six.reraise(c, e, tb)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 80, in tworker
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     rv = meth(*args, **kwargs)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]   File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1065, in createWithFlags
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e]     if ret == -1: raise libvirtError ('virDomainCreateWithFlags() failed', dom=self)
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e] libvirtError: internal error: qemu unexpectedly closed the monitor: 
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e] (process:36773): GLib-WARNING **: gmem.c:482: custom memory allocation vtable not supported
2016-11-05 16:53:07.967 35555 ERROR nova.compute.manager [instance: b2053da9-a7ca-4a90-9e7a-1efd07ee547e] 2016-11-05T15:53:07.752913Z qemu-kvm: CPU feature arat not found