hi,
tried your option but it does not help. (cpu usage is still high)
below my command line syntax:
qemu-system-x86_64 -global mc146818rtc.lost_tick_policy=slew -machine
accel=kvm:tcg -name win7 -S -machine pc-i440fx-1.4,accel=kvm,usb=off -m 2048
-realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid
813f5806-64ec-3319-452a-5e1834e753c9 -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/win7.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime
-no-shutdown -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7 -device
ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x8 -drive
file=/data/vmware/win7.img,if=none,id=drive-virtio-disk0,format=qcow2 -device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
-device usb-tablet,id=input0 -device intel-hda,id=sound0,bus=pci.0,addr=0x4
-device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -vga std