No sure whether it is the same problem or not.Hotplug/hotunplug port  will hit such error: Ncat: Connection refused--->on host

Version:
# uname -r
3.10.0-216.el7.x86_64
# rpm -q qemu-kvm-rhev
qemu-kvm-rhev-2.1.2-16.el7.x86_64

Guest:

3.10.0-216.el7.x86_64


Steps:
1.Boot guest
 ...-device virtio-serial-pci,id=virtio-serial0,max_ports=3,vectors=4,bus=pci.0,addr=0x5 -chardev socket,id=channel0,path=/var/lib/libvirt/qemu/rhel58.channel0,server,nowait -chardev socket,id=channel1,path=/var/lib/libvirt/qemu/rhel58.channel1,server,nowait 

2.hotplug port
{"execute":"device_add","arguments":{"driver":"virtserialport","bus":"virtio-serial0.0","nr":"1","chardev":"channel0","name":
"org.linux-kvm.port.0","id":"port0"}}
{"return": {}}


3.Tried to transfer data-->successfully

4.hotunplug port

{"execute":"device_del","arguments":{"id":"port0"}}

5.hotplug port again
..
{"execute":"device_add","arguments":{"driver":"virtserialport","bus":"virtio-serial0.0","nr":"1","chardev":"channel0","name":
"org.linux-kvm.port.0","id":"port0"}}
{"return": {}}

6.Tried to transfer data
In guest
# cat lang.txt >/dev/vport2p1 

Host:
# nc -U /var/lib/libvirt/qemu/rhel58.channel0
Ncat: Connection refused.


My CLI:
 /usr/libexec/qemu-kvm -enable-kvm -m 8G -smp 8 -name VM -uuid `uuidgen` -nodefaults -rtc base=utc -drive file=iscsi://10.66.90.100:3260/iqn.2001-05.com.equallogic\:0-8a0906-6ca1f7d03-9f7f4a4673153e85-s2-flang-310194/0,if=none,id=drive-data-disk,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop,serial=QEMU-DISK2 -device virtio-scsi-pci,bus=pci.0,addr=0x7,id=scsi1 -device scsi-hd,bus=scsi1.0,drive=drive-data-disk,id=data-disk -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:60:3f:29,addr=0x4 -monitor stdio -boot menu=on,order=d -qmp tcp:0:4447,server,nowait -spice port=8000,disable-ticketing -vga qxl -vga std -device virtio-balloon-pci,bus=pci.0,id=balloon0  -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -device virtio-serial-pci,id=virtio-serial0,max_ports=3,vectors=4,bus=pci.0,addr=0x5 -chardev socket,id=channel0,path=/var/lib/libvirt/qemu/rhel58.channel0,server,nowait -chardev socket,id=channel1,path=/var/lib/libvirt/qemu/rhel58.channel1,server,nowait

*** Bug 1227833 has been marked as a duplicate of this bug. ***