Dear Kyle,
how did you get the KVM guest to start at all? mine failed complaining that iommu group issue
root@vm-ha:~# virsh start kvm-node0
error: Failed to start domain kvm-node0
error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -device vfio-pci,host=07:00.1,id=hostdev0,bus=pci.0,addr=0x6: vf
io: error, group 4 is not viable, please ensure all devices within the iommu_group are bound to their vfio bus driver.
qemu-system-x86_64: -device vfio-pci,host=07:00.1,id=hostdev0,bus=pci.0,addr=0x6: vfio: failed to get group 4
qemu-system-x86_64: -device vfio-pci,host=07:00.1,id=hostdev0,bus=pci.0,addr=0x6: Device initialization failed.
qemu-system-x86_64: -device vfio-pci,host=07:00.1,id=hostdev0,bus=pci.0,addr=0x6: Device 'vfio-pci' could not be initialized
root@vm-ha:~# lspci -s 07:00.1 -k
07:00.1 Network controller: Mellanox Technologies MT27500 Family [ConnectX-3 Virtual Function]
Subsystem: Mellanox Technologies Device 61b0
Kernel driver in use: vfio-pci
root@vm-ha:~# lspci -s 07:00.2 -k
07:00.3 Network controller: Mellanox Technologies MT27500 Family [ConnectX-3 Virtual Function]
Subsystem: Mellanox Technologies Device 61b0
Kernel driver in use: vfio-pci
root@vm-ha:~# lspci -s 07:00.0 -k
07:00.0 Network controller: Mellanox Technologies MT27500 Family [ConnectX-3]
Subsystem: Mellanox Technologies Device 0024
Kernel driver in use: mlx4_core
I notice that my 07:00.0 and 07:00.1 device are both in the same iommmu group
I am also on Ubuntu 14.04.3 and Kernel 3.19