[vfio-users] No available IOMMU models

[Alex Williamson]

On Fri, 2015-08-28 at 18:34 -0500, Mark Nipper wrote:
> 	Ran into a weird problem with my vfio / gpu passthrough
> last night.  I was playing a game under a Windows 10 Pro guest
> when suddenly the game seemed to freeze, I started to get the
> blue spinning wheel pointer from Windows indicating that the
> application wasn't responding suddenly, and then everything went
> dark.  I tried switching back to my Linux host and couldn't get
> it to come up either.  After investigating further on the
> network, the host seemed like it was down completely.
> 
> 	So after a physical reset of the machine, everything came
> up under Linux and I tried starting up my guest again, and now
> I'm getting the following:
> ---
> qemu-system-x86_64: -device vfio-pci,host=02:00.0,bus=root,addr=00.0,multifunction=on,x-vga=on: vfio: No available IOMMU models
> qemu-system-x86_64: -device vfio-pci,host=02:00.0,bus=root,addr=00.0,multifunction=on,x-vga=on: vfio: failed to setup container for group 18
> qemu-system-x86_64: -device vfio-pci,host=02:00.0,bus=root,addr=00.0,multifunction=on,x-vga=on: vfio: failed to get group 18
> qemu-system-x86_64: -device vfio-pci,host=02:00.0,bus=root,addr=00.0,multifunction=on,x-vga=on: Device initialization failed
> qemu-system-x86_64: -device vfio-pci,host=02:00.0,bus=root,addr=00.0,multifunction=on,x-vga=on: Device 'vfio-pci' could not be initialized
> 

This means that the vfio_iommu_type1 module isn't loaded.  You can try
loading it manually via modprobe and see what errors you get.  If it's
not there, verify CONFIG_VFIO_IOMMU_TYPE1 in your current kernel config.