[vfio-users] Strange behavior with recent update. ACS(?) & VFIO

[Mark]

Hi,

Today I updated my arch linux system. It had only been a week since the
last update.  Not notices applicable to my update had been posted.

My setup is a Intel i7-4790S, ASRock mobo supporting vt-d and all the
goodies.

I have libvirt using virt-manager for my win7 VM, with nvidia 750 gpu and
hdmi audio device passed through to it, also the onboard intel audio
controller (non-hdmi).  These 3 devices are all on the same iommu group.

Before the update, while the VM was powered off, my host played audio
through the onboard intel audio controller.  When the VM was on, audio from
the VM played through the onboard audio controller and the host lost audio
output.  This is the desired behavior.  Another behavior in the past was to
only assign the gpu and hdmi audio on the gpu, but leave the onboard audio
unassigned to vfio.

After the update, pulse audio no longer reports audio devices in the host.
Trying to figure out why this is, I've removed all passthrough devices from
all VMs in virt-manager, removed the vfio module load options, but vfio_pci
still claims the 3 devices.  The only way I've been able to get the audio
devices back is to BLACKLIST the vfio module.

My questions are:

1. Is there any other way besides /etc/modules.d/vfio.conf that vfio could
be told to claim a device on boot?
2. Is ACS impacting my ability to have the host use a device claimed by
iommu because of a recent change?
3. Is there another way of going about assigning a claimed device to the
host?
4. Can I no longer only assign 2 of 3 devices in an iommu group to vfio?

Thank you
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