kvm: fix wrong VM CPU usage (#4381)

Author: ustcweizhou

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -75,7 +75,6 @@
 import org.libvirt.LibvirtException;
 import org.libvirt.MemoryStatistic;
 import org.libvirt.Network;
-import org.libvirt.NodeInfo;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
@@ -3627,8 +3626,7 @@ public VmStatsEntry getVmStat(final Connect conn, final String vmName) throws Li
                 elapsedTime = now.getTimeInMillis() - oldStats._timestamp.getTimeInMillis();
                 double utilization = (info.cpuTime - oldStats._usedTime) / ((double)elapsedTime * 1000000);
 
-                final NodeInfo node = conn.nodeInfo();
-                utilization = utilization / node.cpus;
+                utilization = utilization / info.nrVirtCpu;
                 if (utilization > 0) {
                     stats.setCPUUtilization(utilization * 100);
                 }