[vfio-users] Latest Windows 10 “feature” update breaks IGD passthrough

[Manuel Ullmann]

> so you could for example enter OVMF setup or the EFI console and
> things would be fine. They appeared instead once Windows started
> booting. I tested an Arch Linux ISO in the virtual machine and had
> similar results after I got past the boot menu.
That would be at the same stage as for me.  I’m using IGD passthrough
though and thus boot via Seabios.  Besides it’s also fixed once it has
booted to the Desktop.  I will wait for the next update to check,
whether they still are shown during update processing.

> Does your IGD get claimed by vfio-pci right away at boot?
Yes.  I can’t think of a way, that anything grabs my card anymore.  I
use my own initramfs source and therefore wrote its init script.  I’ve
modified the grub config generation scripts to create a second boot
entry for my host linux, which boots into the qemuvm runlevel (using
OpenRC).  I then parse the cmdline in the init script to do the
following:

if ! [[ ${cmdline##* } == "softlevel=qemuvm" ]]; then
    modprobe -vvv i915 2>/rd.debug.log
    echo "modprobeReached" >>/rd.debug.log
else
    modprobe vfio-pci ids=8086:0412
    echo "modprobedVfio" >>/rd.debug.log
fi
echo "modprobeFinished" >>/rd.debug.log

All modules and their dependencies have been *moved* to the initramfs
source, so that the host Linux can’t autoload i915, when I’m starting
the VM.  I use a script for that during kernel updates.  I’ve also
removed all *fb drivers from the kernel, especially simplefb and efifb,
so i915 is the only existing framebuffer driver.  The host is booted in
UEFI only mode (no CSM).

Thanks,
Manuel