Description of problem:


Version-Release number of selected component (if applicable):


How reproducible:
100%

Steps to Reproduce:
1.boot guest with balloon device:
/usr/libexec/qemu-kvm \
    -monitor stdio  \
    -name 'avocado-vt-vm1'  \
    -sandbox off  \
    -machine q35  \
    -nodefaults \
    -device VGA,bus=pcie.0,addr=0x1 \
    -device pcie-root-port,id=pcie.0-root-port-5,slot=5,chassis=5,addr=0x5,bus=pcie.0 \
    -device qemu-xhci,id=usb1,bus=pcie.0-root-port-5,addr=0x0 \
    -device pcie-root-port,id=pcie.0-root-port-6,slot=6,chassis=6,addr=0x6,bus=pcie.0 \
    -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie.0-root-port-6,addr=0x0 \
    -drive id=drive_image1,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/win2019-64-virtio-scsi.qcow2 \
    -device scsi-hd,id=image1,drive=drive_image1 \
    -device pcie-root-port,id=pcie.0-root-port-7,slot=7,chassis=7,addr=0x7,bus=pcie.0 \
    -device virtio-net-pci,mac=9a:ac:ad:ae:af:b0,id=id3MOJiK,vectors=4,netdev=idAOrAbG,bus=pcie.0-root-port-7,addr=0x0  \
    -netdev tap,id=idAOrAbG,vhost=on,script=/etc/qemu-ifup \
    -m 14336  \
    -smp 24,maxcpus=24,cores=12,threads=1,sockets=2  \
    -cpu 'Skylake-Server',+kvm_pv_unhalt,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time \
    -drive id=drive_cd1,if=none,snapshot=off,aio=threads,cache=none,media=cdrom,file=/home/kvm_autotest_root/iso/windows/winutils.iso \
    -device scsi-cd,id=cd1,drive=drive_cd1 \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
    -vnc :1  \
    -rtc base=localtime,clock=host,driftfix=slew  \
    -boot order=cdn,once=c,menu=off,strict=off \
    -enable-kvm \
    -qmp tcp:0:4444,server,nowait \
    -device pcie-root-port,id=pcie.0-root-port-8,slot=8,chassis=8,addr=0x8,bus=pcie.0 \
    -device virtio-balloon-pci,id=balloon0,bus=pcie.0-root-port-8,addr=0x0


2.install balloon service in guest:
# blnsrv.exe -i

3.hot-unplug balloon device:
(qemu) device_del balloon0 

Actual results:
balloon device still in guests

Expected results:
balloon device can be unplug correctly.

Additional info:
1. Downgrade driver to build 154, unplug can be finished without any error, so it's a regression bug