Description of problem:
I have only 1 scsi controller#0 defined in guest. And I hotplug scsi device with a bad address. After that, vm is killed. It cannot be reproduced with qemu-7.2.z

Version-Release number of selected component (if applicable):
qemu-kvm-rhev-2.6.0-9.el7.x86_64
libvirt-1.3.5-1.el7.x86_64
3.10.0-445.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. prepare a running vm
 <controller type='scsi' index='0'>
      <alias name='scsi0'/>
      <address type='pci' domain='0x0000' bus='0x01' slot='0x01' function='0x0'/>
    </controller>

# virsh start vm1
Domain vm1 started
# virsh list
 Id    Name                           State
----------------------------------------------------
 70    vm1                            running

#ps -ef|grep qemu
/usr/libexec/qemu-kvm -name guest=vm1,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-37-vm1/master-key.aes -machine pc-i440fx-rhel7.2.0,accel=kvm,usb=off -m 1024 -realtime mlock=off -smp 4,sockets=1,cores=2,threads=2 -uuid 471fc3b6-6079-4c92-a027-414878a4f4db -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-37-vm1/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=0 -boot strict=on -device pci-bridge,chassis_nr=1,id=pci.1,bus=pci.0,addr=0xb -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x6.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x6 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x6.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x6.0x2 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x7 -device ahci,id=sata0,bus=pci.0,addr=0x8 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive file=/mnt/nfs2/RHEL-7.3-latest.qcow2,format=qcow2,if=none,id=drive-virtio-disk0 -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x9,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/var/lib/libvirt/images/boot.iso,format=raw,if=none,id=drive-ide0-0-0,readonly=on -device ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -netdev tap,fd=27,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:5d:44:cb,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -spice port=5901,addr=127.0.0.1,disable-ticketing,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa -sandbox on -msg timestamp=on

2. hotplug scsi hostdev(passthrough) with incorrect address

# lsscsi
[0:0:0:0]    disk    ATA      SAMSUNG HD322GM  0101  /dev/sda 
[2:0:0:0]    cd/dvd  PLDS     DVD-ROM DH-16D5S VD15  /dev/sr0 
[6:0:0:0]    disk    Alcor    Flash Disk       8.07  /dev/sdb

# qemu-img info /dev/sdb
image: /dev/sdb
file format: raw
virtual size: 999M (1047527424 bytes)
disk size: 0


# cat hostdev.xml
<hostdev mode='subsystem' type='scsi' managed='no'>
      <source>
        <adapter name='scsi_host6'/>
        <address bus='0' target='0' unit='0'/>
      </source>
<address type='drive' controller='0' bus='1' target='1' unit='0'/>
    </hostdev>

# virsh attach-device vm1 hostdev.xml
error: Failed to attach device from hostdev.xml
error: internal error: unable to execute QEMU command 'device_add': bad scsi channel id: 1

3. check vm status
# virsh list --all
 Id    Name                           State
----------------------------------------------------
 -     vm1                            shut off

Actual results:
vm is killed after hotplug scsi device fails

Expected results:
vm is usable after hotplug scsi device fails

Additional info:
cat /var/log/libvirtd.log

2016-06-30 05:29:58.645+0000: 20219: info : qemuMonitorSend:1007 : QEMU_MONITOR_SEND_MSG: mon=0x7f8b70009760 msg={"execute":"__com.redhat_drive_add","arguments":{"file":"/dev/sg2","id":"drive-hostdev0"},"id":"libvirt-50"}^M
 fd=-1
2016-06-30 05:29:58.645+0000: 20214: info : qemuMonitorIOWrite:531 : QEMU_MONITOR_IO_WRITE: mon=0x7f8b70009760 buf={"execute":"__com.redhat_drive_add","arguments":{"file":"/dev/sg2","id":"drive-hostdev0"},"id":"libvirt-50"}^M
 len=110 ret=110 errno=0

2016-06-30 05:29:58.647+0000: 20219: info : qemuMonitorSend:1007 : QEMU_MONITOR_SEND_MSG: mon=0x7f8b70009760 msg={"execute":"device_add","arguments":{"driver":"scsi-generic","bus":"scsi0.0","channel":"1","scsi-id":"1","lun":"0","drive":"drive-hostdev0","id":"hostdev0"},"id":"libvirt-51"}

2016-06-30 05:29:58.647+0000: 20214: info : qemuMonitorIOWrite:531 : QEMU_MONITOR_IO_WRITE: mon=0x7f8b70009760 buf={"execute":"device_add","arguments":{"driver":"scsi-generic","bus":"scsi0.0","channel":"1","scsi-id":"1","lun":"0","drive":"drive-hostdev0","id":"hostdev0"},"id":"libvirt-51"}^M
 len=177 ret=177 errno=11

cat /var/log/libvirt/qemu/vm1.log
main_channel_link: add main channel client
main_channel_handle_parsed: net test: latency 0.176000 ms, bitrate 1407560137 bps (1342.353951 Mbps)
red_dispatcher_set_cursor_peer:
inputs_connect: inputs channel client create
WARNING: Image format was not specified for '/dev/sg2' and probing guessed raw.
         Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions.
2016-06-30 06:00:47.592+0000: shutting down