> This guide still indicates support for 4th generation (aka
> Haswell), but I don't know how accurate it is:
>
> https://github.com/01org/gvt-linux/wiki/GVTg_Setup_Guide

Probabily a typo or oversight. Here is a quote straight from one of the Intel 
devs from less than a month ago on iGVT-g Mailing List:
https://lists.01.org/pipermail/igvt-g/2016-November/001024.html

Q: Will Haswell ever be put back into the validation matrix and possibly 
considered for KVM support?
A: Unfortunately, the answer is no. :(
KVMGT supported platform starts from Broadwell (including Broadwell). We have 
no plan to add Haswell platform code into KVMGT because Broadwell GPU has big 
difference with Haswell's.


The "validation matrix" question for Haswell was regarding XenGT support, since 
XenGT still supports it but should receive much less validation than before, 
thus they may not catch regressions.



> One of the advantages of the vfio mediated device interface is that API
> exposed to the user, and thus QEMU, is identical to a directly assigned
> device.  Therefore AFAIK, there are no QEMU changes necessary for
> KVMGT.
As far that I recall, QEMU modifications were required because iGVT-g added a 
lot of new invokation parameters, but I checked the new KVMGT Setup Guide you 
linked, and it seems that they changed the procedure a bit.

As of Sep 2016, according to near the end of this file:
https://01.org/igvt-g/blogs/wangbo85/2016/kvmgt-environment-setup-guide-using-gvt-g-installation-iso
...in order to use iGVT-g in a VM, you had to invoke QEMU using these custom 
parameters:

-vgt
-vga vgt
-vgt_high_gm_sz 384
-vgt_fence_sz 4
-vgt_low_gm_sz 128


On the guide you listed, here:
https://github.com/01org/gvt-linux/wiki/GVTg_Setup_Guide
...instead, you use some command line parameters to create a vGPU in the host, 
then invoke QEMU with -device vfio-pci as if you were doing Passthrough but 
with a sysfsdev parameter pointing to the vGPU:

-vga none
-device isa-vga
-device 
vfio-pci,sysfsdev=/sys/bus/pci/devices/0000:00:02.0/894f3983-1a36-42b3-b52c-1024aca216be


I didn't followed what changes they did to get the iGVT-g support upstream, but 
previously QEMU also needed a few tweaks to work with it. I suppose that some 
logic that they used to do in their custom QEMU got moved into the Kernel and 
thus it may work without further modifications, as you said.
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