1. uname -a
Linux phys08 3.13.0-39-generic #66-Ubuntu SMP Tue Oct 28 13:30:27 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

2. dpkg -l | egrep '(ifenslave|bridge-utils|qemu-kvm)' | awk '{print $2 " " $3}'
bridge-utils  1.5-6ubuntu2
ifenslave     2.4ubuntu1
qemu-kvm      2.0.0+dfsg-2ubuntu1.6

3. My boot logs:
dmesg | egrep renamed
[   10.468243] systemd-udevd[287]: renamed network interface eth1 to em2
[   10.616282] systemd-udevd[291]: renamed network interface eth0 to em1
[   17.162783] systemd-udevd[753]: renamed network interface em2 to em5
[   17.214829] systemd-udevd[722]: renamed network interface em1 to em2
[   17.466872] systemd-udevd[763]: renamed network interface eth0 to em4
[   17.530987] systemd-udevd[716]: renamed network interface eth1 to em3

dmesg | egrep em[0-9]
[   10.468243] systemd-udevd[287]: renamed network interface eth1 to em2
[   10.616282] systemd-udevd[291]: renamed network interface eth0 to em1
[   17.162783] systemd-udevd[753]: renamed network interface em2 to em5
[   17.214829] systemd-udevd[722]: renamed network interface em1 to em2
[   17.466872] systemd-udevd[763]: renamed network interface eth0 to em4
[   17.530987] systemd-udevd[716]: renamed network interface eth1 to em3
[   18.110150] bonding: bond0: Adding slave em5.
[   18.211203] IPv6: ADDRCONF(NETDEV_UP): em5: link is not ready
[   18.211206] device em5 entered promiscuous mode
[   18.211271] bonding: bond0: enslaving em5 as an active interface with a down link.
[   18.211277] bonding: bond0: Adding slave em4.
[   18.314490] ixgbe 0000:81:00.1: registered PHC device on em4
[   18.747701] IPv6: ADDRCONF(NETDEV_UP): em4: link is not ready
[   18.747704] device em4 entered promiscuous mode
[   18.768714] bonding: bond0: enslaving em4 as an active interface with a down link.
[   18.768719] bonding: bond0: Adding slave em2.
[   18.863574] IPv6: ADDRCONF(NETDEV_UP): em2: link is not ready
[   18.863576] device em2 entered promiscuous mode
[   18.863631] bonding: bond0: enslaving em2 as an active interface with a down link.
[   18.864556] bonding: bond0: Adding slave em3.
[   18.969311] ixgbe 0000:81:00.0: registered PHC device on em3
[   19.368609] IPv6: ADDRCONF(NETDEV_UP): em3: link is not ready
[   19.368617] device em3 entered promiscuous mode
[   19.389583] bonding: bond0: enslaving em3 as an active interface with a down link.
[   21.652782] igb: em5 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[   21.700444] bonding: bond0: link status definitely up for interface em5, 1000 Mbps full duplex.
[   21.812340] ixgbe 0000:81:00.1 em4: NIC Link is Up 1 Gbps, Flow Control: None
[   21.900528] bonding: bond0: link status definitely up for interface em4, 1000 Mbps full duplex.
[   22.269021] igb: em2 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[   22.304702] bonding: bond0: link status definitely up for interface em2, 1000 Mbps full duplex.
[   22.857639] ixgbe 0000:81:00.0 em3: NIC Link is Up 1 Gbps, Flow Control: None
[   22.909015] bonding: bond0: link status definitely up for interface em3, 1000 Mbps full duplex.

dmesg | grep bonding
[   16.512356] bonding: Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)
[   17.844166] bonding: bond0: Setting MII monitoring interval to 100.
[   17.844786] bonding: bond0: unable to update mode because interface is up.
[   18.020201] bonding: bond0: Unable to update LACP rate because bond is not in 802.3ad mode.
[   18.110150] bonding: bond0: Adding slave em5.
[   18.211271] bonding: bond0: enslaving em5 as an active interface with a down link.
[   18.211277] bonding: bond0: Adding slave em4.
[   18.768714] bonding: bond0: enslaving em4 as an active interface with a down link.
[   18.768719] bonding: bond0: Adding slave em2.
[   18.863631] bonding: bond0: enslaving em2 as an active interface with a down link.
[   18.864556] bonding: bond0: Adding slave em3.
[   19.389583] bonding: bond0: enslaving em3 as an active interface with a down link.
[   21.700444] bonding: bond0: link status definitely up for interface em5, 1000 Mbps full duplex.
[   21.700451] bonding: bond0: first active interface up!
[   21.900528] bonding: bond0: link status definitely up for interface em4, 1000 Mbps full duplex.
[   22.304702] bonding: bond0: link status definitely up for interface em2, 1000 Mbps full duplex.
[   22.909015] bonding: bond0: link status definitely up for interface em3, 1000 Mbps full duplex.
`

4. Configs:
/etc/network/interfaces
auto lo
iface lo inet loopback

auto br0
iface br0 inet static
        bridge_ports bond0
        address 10.0.100.8
        netmask 255.255.0.0
        gateway 10.0.0.1
        bridge_stp off
        bridge_fd 0
        bridge_maxwait 0

auto bond0
        iface bond0 inet manual
        bond-mode 0
        bond-miimon 100
        bond-lacp-rate 1
        bond-slaves none

auto em2
iface em2 inet manual
        bond-master bond0

auto em3
iface em3 inet manual
        bond-master bond0

auto em4
iface em4 inet manual
        bond-master bond0

auto em5
iface em5 inet manual
        bond-master bond0

virsh edit test
<domain type='kvm'>
  <name>test</name>
  <uuid>b64b0bb6-68c5-11e4-9aeb-52540002eb97</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static'>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-1.0'>hvm</type>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/opt/test.img'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/opt/iso/ubuntu-14.04-server-amd64.iso'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='1' target='0' unit='0'/>
    </disk>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <interface type='bridge'>
      <mac address='52:54:00:27:65:0b'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='vnc' port='10111' autoport='no' listen='*'>
      <listen type='address' address='*'/>
    </graphics>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </memballoon>
  </devices>
</domain>