Description of problem:
Qemu monitor "system_powerdown" command fail to power down guest, th VM will be in paused (suspended) status, but cann't to wakeup successully via system_wakeup command.
If run 'poweroff' in guest terminal which can power down guest succefully.

Version-Release number of selected component (if applicable):
host info:
3.10.0-60.el7.x86_64
qemu-kvm-rhev-1.5.3-21.el7.x86_64
seabios-1.7.2.2-4.el7.x86_64
guest info:
3.10.0-60.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.boot up a rhel7.0 guest.
2.login guest using root user.
3.send "system_powerdown" qemu monitor command.

Actual results:
after step 3, the guest screen will be in blank screen and fail to powerdown, the guest kernel message output nothing after send "system_powerdown". check the VM status is paused(suspended) but fail to wakeup via 'system_wakeup'.
(qemu) system_powerdown 
(qemu) info status 
VM status: paused (suspended)
(qemu) cont
(qemu) info status 
VM status: paused (suspended)
(qemu) system_wakeup 
(qemu) info status 
VM status: running

Expected results:
it should power down guest successfully.

Additional info:
# /usr/libexec/qemu-kvm -M pc -S -cpu SandyBridge -enable-kvm -m 2048 -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -usb -device usb-tablet,id=input0 -name sluo -uuid 990ea161-6b67-47b2-b803-19fb01d30d30 -rtc base=localtime,clock=host,driftfix=slew -device virtio-serial-pci,id=virtio-serial0,max_ports=16,vectors=0,bus=pci.0,addr=0x3 -chardev socket,id=channel1,path=/tmp/helloworld1,server,nowait -device virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port1 -chardev socket,id=channel2,path=/tmp/helloworld2,server,nowait -device virtserialport,chardev=channel2,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port2 -drive file=iscsi://10.66.90.100:3260/iqn.2001-05.com.equallogic:0-8a0906-4c41f7d03-453f49b421052a57-s2-sluo-270305-1/0,if=none,id=drive-system-disk,cache=none,format=raw,aio=native,werror=stop,rerror=stop,discard=on -iscsi id=iqn0 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4,num_queues=4 -device scsi-block,drive=drive-system-disk,bus=scsi0.0,id=libiscsi-system-disk,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device rtl8139,netdev=hostnet0,id=rtl8139-net-pci0,mac=00:01:02:B6:40:21,bus=pci.0,addr=0x5 -device virtio-balloon-pci,id=ballooning,bus=pci.0,addr=0x6 -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -k en-us -boot menu=on -qmp tcp:0:4444,server,nowait -serial unix:/tmp/ttyS0,server,nowait -vnc :1 -spice disable-ticketing,port=5931 -monitor stdio