KVM: 0.945
semantic: 0.944
device: 0.931
graphic: 0.928
performance: 0.907
other: 0.887
debug: 0.879
PID: 0.874
files: 0.871
permissions: 0.869
network: 0.858
socket: 0.815
vnc: 0.787
boot: 0.691

vfio passtrhough fails at 'No available IOMMU models' on Intel BDW-EP platform

Environment:
 ------------
 Host OS (ia32/ia32e/IA64): ia32e
 Guest OS (ia32/ia32e/IA64): ia32e
 Guest OS Type (Linux/Windows): linux
 kvm.git Commit: da3f7ca3
 qemu.git Commit: 38a762fe 
 Host Kernel Version: 4.4.0-rc2
 Hardware: BDW EP (Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz, Grantley-EP)

Bug description:
 --------------------------
 when create guest with vt-d assignment using vfio-pci driver, the guest can not be created.
Warning 'No available IOMMU models'


Reproduce steps:
 ----------------
 1. bind device to vfio-pci driver
 2. qemu-system-x86_64 -enable-kvm -m 512 -smp 2 -device vfio-pci,host=81:00.0 -net none -drive file=rhel7u2.qcow2,if=none,id=virtio-disk0 -device virtio-blk-pci,drive=virtio-disk0

Current result:
 ----------------
 qemu-system-x86_64: -device vfio-pci,host=81:00.0: vfio: No available IOMMU models
 qemu-system-x86_64: -device vfio-pci,host=81:00.0: vfio: failed to setup container for group 41
 qemu-system-x86_64: -device vfio-pci,host=81:00.0: vfio: failed to get group 41
 qemu-system-x86_64: -device vfio-pci,host=81:00.0: Device initialization failed

Expected result:
 ----------------
 guest can be created
Basic root-causing log:
 ----------------------




You've somehow managed to not load the vfio_iommu_type1 module.  The vfio module will request it when loading, if the module is not available when loading, such as from an initramfs that does not include the full set of vfio modules, it will need to be loaded later manually.

You're right. After I manually load vfio_iommu_type1, the error is gone.