Re: [Qemu-devel] [PATCH v9 00/12] Add Mediated device support

[Gerd Hoffmann]

  Hi,

> Just want to share that we have published a KVMGT implementation
> based on this v9 patchset, to:
> 
>       https://github.com/01org/gvt-linux/tree/gvt-next-kvmgt
> 
> It doesn't utilize common routines introduced by 05+ patches yet.
> The complete intel vGPU device-model is contained.

Tried to use this implementation.  Used the
topic/gvt-next-kvmgt-mdev-2016-11-18 branch which looked like the most
recent one.  Setup:

  * Everything compiled as modules.
  * iommu turned off for the igd (intel_iommu=on,igfx_off).
  * Blacklisted i915 so dracut initrd doesn't load it
    (rd.driver.blacklist=i915)
  * tweaked module config so kvmgt is loaded before i915,
    also enable gvt:

      # cat /etc/modprobe.d/kraxel-gvt.conf 
      options i915 enable_gvt=1
      softdep i915 pre: kvmgt

Everything seems to load fine.  Sysfs files are there, and I can create
vgpus.

Trying to assign a vgpu this way:

  -device vfio-pci,sysfsdev=/sys/class/mdev_bus/0000:00:02.0/<uuid>

fails though and gives this message in the kernel log:

  [  402.560350] [drm:intel_vgpu_open [kvmgt]] *ERROR* gvt: KVM is
required to use Intel vGPU

Trying the same with a mtty sample device works and I can see the pci
serial device in the guest.

Any clues what is going wrong?

Has this version any support for exporting the guest display as dma-buf,
so qemu can show it?  Or is this a headless vgpu?

thanks,
  Gerd