Description of problem:


Version-Release number of selected component (if applicable):
[root@localhost Desktop]# uname -r
2.6.32-131.0.10.el6.x86_64
# rpm -q qemu-kvm
qemu-kvm-0.12.1.2-2.160.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1. start VM with -chardev
eg: <CLI> -monitor stdio \
-chardev socket,id=s11,path=/tmp/tt11,server,nowait \
-chardev socket,id=s12,path=/tmp/tt12,server,nowait \
-chardev socket,id=s13,path=/tmp/tt13,server,nowait \

2.Hot add virtio-serial-bus
(qemu) device_add virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x8

3.hot add 1st virtioserialport
(qemu)device_add virtserialport,chardev=s11,name=org.linux-kvm.port.11,bus=virtio-serial0.0,id=port11

4.in the guest send data to /dev/vport0p1 
in the guest #echo c > /dev/virtio-ports/org.linux-kvm.port.11
on the host  #nc -U /tmp/tt11
(after step 4 ,socket could receive data)

5.hot add another virtioserialport
(qemu)device_add virtserialport,chardev=s12,name=org.linux-kvm.port.12,bus=virtio-serial0.0,id=port12

6.in the guest send data to /dev/vport0p2
in the guest #echo c > /dev/virtio-ports/org.linux-kvm.port.12
on the host  #nc -U /tmp/tt12
(after step 6 ,socket could receive data)

7.Hot unplug the 2nd virtio serial port
(qemu)device_del port12
(after step7 ,/dev/vport0p2 removed)

8.send data via /dev/vport0p1 in the guest


Actual Results:
After step8,guest could not transfer data via /dev/vport0p1

Expected Results:
After step8,guest still can send data via /dev/vport0p1