Re: [Qemu-devel] Status IGD pass-through with QEMU/KVM

[Alex Williamson]

On Wed, 2015-01-28 at 16:02 +0100, Jan Kiszka wrote:
> Hi Alex,
> 
> before getting dirty fingers in vain: what is the current status of
> handing an IGD GPU to a KVM guest, specifically Windows? I found some
> related QEMU patches from last year on the list, but it seems they
> didn't progress. Are there open issues without known solutions or is it
> "just" about putting pieces together - given that there related patches
> for Xen floating around?

Hi Jan,

The patches submitted last year by Andrew Barnes are functional (AFAIK),
but mostly proof-of-concept quality.  They make use of /dev/mem in place
of designing VFIO interfaces, they hack into various chipset code, etc.
Based on the attempts to port the Xen IGD code into QEMU, I think Intel
was working on reducing the machine level impact of IGD assignment with
a "universal" driver, but I haven't seen any status updates on that for
some time.  If Intel is successful in creating such a driver, then IGD
assignment may be no more complicated that discrete assignment (but
might only support very new HW).  To support current hardware and
drivers, we need to expose not only the IGD device, but manipulate
chispet device IDs and punch through registers and opregions on other
devices.  Andrew's patches do this, but need help to architect
interfaces and break down the code into upstream-able chunks.  Thanks,

Alex