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Re: [vfio-users] gpus are still within the same iommu group, kernel 4.4.0, i7 6700





On Thu, Jun 9, 2016 at 3:59 AM, <lucas herich net> wrote:
Hello everyone,

I am running a fresh Ubuntu 16.04 and want to use kvm/qemu to run a windows VM with a gpu passthrough, however after patching the kernel both gpus are still within the same iommu group 1.
My system:
- Intel Core i7 6700
- Gigabyte GA-Z170X-UD5 TH Intel Z170
- 1x GeForce GTX 650 Ti (used by the host)
- 1x GeForce GTX 960 (used by the vm)

I am not so well versed with linux, so I read lots of tutorials and howtos. However I am kind of stuck right now and do not even know how to verify if I used the correct patches (Alex commented within the first patch: "This doesn't fix what lspci shows.").
Hopefully someone could give me an advice how to proceed from here or if I should give up.

That is what I have done:
* install Ubuntu 16.04 (kernel version 4.4.0)
* install kvm, quemu and so on
* let vfio-pci grab the GTX 960 (see [1] and [2])
* install nvidia driver for the GTX 650 Ti
* build patched kernel (see [3])
* start virtual machine manager
* create a vm with windows 7
* adding passthrough gpu from slot 2 results in (details see [4]): vfio: error, group 1 is not viable, please ensure all devices within the iommu_group are bound to their vfio bus driver

You're overlooking an important qualifier of the patches you're using, they only enable isolation of devices downstream of *PCH* root ports.  I don't see a block diagram of the layout in your motherboard manual, but this is only going to affect the root ports at address 00:1c.*.  As always on Intel, you need to use a High End Desktop Processor or Xeon E5 or better CPU to get isolation of the processor root ports (or use the ACS override patch that I don't support).  Thanks,

Alex 


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