Description of problem:
 I tried to hot remove the pci device (NIC card) using the following commands:
1.(qemu) info network 
VLAN 0 devices:
  tap.0: ifname=tap0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
  virtio.0: model=virtio,macaddr=22:11:22:45:66:83
2. (qemu) host_net_remove 0 tap.0
3.(qemu) pci_del pci_addr=3
4.(qemu) info network 
VLAN 0 devices:
  virtio.0: model=virtio,macaddr=22:11:22:45:66:83
5.(qemu) info pci
  ..............
  Bus  0, device   3, function 0:
    Ethernet controller: PCI device 1af4:1000
      IRQ 11.
      BAR0: I/O at 0xc040 [0xc05f].

It's failed.

Version-Release number of selected component (if applicable):
#rpm -qa | grep kvm
kvm-qemu-img-83-204.el5
kvm-debuginfo-83-204.el5
etherboot-roms-kvm-5.4.4-13.el5
kvm-tools-83-204.el5
kmod-kvm-83-204.el5
etherboot-zroms-kvm-5.4.4-13.el5
kvm-83-204.el5


How reproducible:


Steps to Reproduce:
1.boot 2008 r2 guest.
#/usr/libexec/qemu-kvm -no-hpet -usbdevice tablet -rtc-td-hack -m 2G -smp 2 -drive file=/root/zhangjunyi/win2008-r2-virtio.qcow2,if=virtio,boot=on,werror=stop -drive file=/root/zhangjunyi/mnt/win2008/Windows_Server_2008_R2_GA_EN.iso,media=cdrom -fda /usr/share/virtio-win/virtio-drivers-1.0.0-45801-1.0.0.vfd -net nic,vlan=0,macaddr=22:11:22:45:66:83,model=virtio -net tap,vlan=0,script=/etc/qemu-ifup -uuid `uuidgen` -cpu qemu64,+sse2 -balloon none -boot d -monitor stdio -vnc :10 -notify all
2.Issue the following commands
2.1.(qemu) info network 
VLAN 0 devices:
  tap.0: ifname=tap0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
  virtio.0: model=virtio,macaddr=22:11:22:45:66:83
2.2 (qemu) host_net_remove 0 tap.0
2.3(qemu) pci_del pci_addr=3
2.4(qemu) info network 
VLAN 0 devices:
  virtio.0: model=virtio,macaddr=22:11:22:45:66:83
2.5(qemu) info pci
  ..............
  Bus  0, device   3, function 0:
    Ethernet controller: PCI device 1af4:1000
      IRQ 11.
      BAR0: I/O at 0xc040 [0xc05f].

  
Actual results:
The NIC card can not be removed from guest.

Expected results:
The NIC card can be removed successfully.

Additional info:

1. If issue command pci_del pci_addr=3 earlier than command "host_net_remove",The NIC card can be removed successfully.

1.1(qemu) info network 
VLAN 0 devices:
  tap.0: ifname=tap0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
  virtio.0: model=virtio,macaddr=22:11:22:45:66:83
1.2 (qemu) pci_del pci_addr=3
1.3 (qemu) host_net_remove 0 tap.0
/etc/qemu-ifdown: could not launch network script
1.4 (qemu) info network 
VLAN 0 devices:
1.5 (qemu) info pci (function 3 was removed)
  Bus  0, device   0, function 0:
    Host bridge: PCI device 8086:1237
  Bus  0, device   1, function 0:
    ISA bridge: PCI device 8086:7000
  Bus  0, device   1, function 1:
    IDE controller: PCI device 8086:7010
      BAR4: I/O at 0xc000 [0xc00f].
  Bus  0, device   1, function 2:
    USB controller: PCI device 8086:7020
      IRQ 10.
      BAR4: I/O at 0xc020 [0xc03f].
  Bus  0, device   1, function 3:
    Bridge: PCI device 8086:7113
      IRQ 9.
  Bus  0, device   2, function 0:
    VGA controller: PCI device 1013:00b8
      BAR0: 32 bit memory at 0xc2000000 [0xc3ffffff].
      BAR1: 32 bit memory at 0xc4000000 [0xc4000fff].
  Bus  0, device   4, function 0:
    SCSI controller: PCI device 1af4:1001
      IRQ 10.
      BAR0: I/O at 0xc080 [0xc0bf].

2.I also tested rhel6. The NIC card can be removed successfully.now matter which command is issue first.