Description of problem:
When executing '(qemu)system_powerdown' in the host, the guest fails shutting down and it is frozen. BTW, it can be shut down successfully by executing 'shutdown -h now' in guest. 


Version-Release number of selected component (if applicable):
Host:
kernel:2.6.32-610.el6.x86_64
qemu-kvm:qemu-kvm-0.12.1.2-2.487.el6.x86_64

Guest:
kernel:kernel:kernel-3.10.0-327.11.1.el7


How reproducible:
100%

Steps to Reproduce:

1.start a linux guest
/usr/libexec/qemu-kvm \
-name rhel6.6.0 \
-machine rhel6.6.0,accel=kvm \
-realtime mlock=off \
-cpu SandyBridge \
-m 8G   \
-smp 8,cores=4,threads=1,sockets=4  \
-uuid 49a3438a-70a3-4ba8-92ce-3a05e0934608 \
-nodefaults \
-rtc base=utc,driftfix=slew \
-monitor unix:/tmp/monitor,server,nowait \
-global kvm-pit.lost_tick_policy=discard \
-global PIIX4_PM.disable_s3=1 \
-global PIIX4_PM.disable_s4=1 \
-boot order=c,menu=on,strict=on \
-device virtio-scsi-pci,id=scsi \
-drive file=/home/0201/rhel7.img,if=none,format=qcow2,id=drive-virtio-scsi,werror=stop,rerror=stop \
-device scsi-hd,drive=drive-virtio-scsi,id=virtio-scsi,bus=scsi.0,scsi-id=0 \
-netdev tap,id=hostnet0,vhost=on \
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1a:4a:42:0a:00 \
-monitor stdio \
-qmp tcp:0:4466,server,nowait -serial unix:/tmp/ttym,server,nowait \
-vga qxl \
-spice port=5912,addr=0.0.0.0,disable-ticketing,seamless-migration=on \
-k en-us \

2.shut down the guest in host
(qemu) system_powerdown
(qemu) inputs_detach_tablet: 
(qemu) 
(qemu) info status
VM status: running



Actual results:
The guest fails shut down and it is frozen.


Expected results:
The guest shut down successfully without any problem.

Another info:
1. Also can reproduced with kernel-2.6.32-573.20.1.el6.x86_64 and qemu-kvm-0.12.1.2-2.487.el6.x86_64 （guest kernel:kernel-3.10.0-327.11.1.el7）
2. The issue didn't reproduced with rhel6.7 guest