Based on the output of this:
ls -1 /sys/kernel/iommu_groups/*/devices/
the [4x:xx.x] devices you are looking for are not in any IOMMU groups, so they aren't eligible to be bound to vfio-pci or passed through to a VM.
I haven't seen devices like this that are completely outside of IOMMU groups. Open to suggestions here.
I've done some digging on this - here's what I found.
Mount unraid share system on my mac and check its spotlight status:
[macbook-pro]:~ $ mdutil -s /Volumes/system
/System/Volumes/Data/Volumes/system:
Server search enabled.
[macbook-pro]:~ $
But as best I can tell "server search" is not in fact enabled.
Turns out samba 4.12.0 changed this search-related default:
Note that when upgrading existing installations that
are using the previous default Spotlight backend
Gnome Tracker must explicitly set "spotlight backend = tracker"
as the new default is "noindex".
If I add the following to SMB extras:
[global]
spotlight backend = tracker
in addition to this share-specific code:
[system]
path = /mnt/user/system
spotlight = yes
Search works again!
When I check spotlight status I get the following:
[macbook-pro]:~ $ mdutil -s /Volumes/system
/System/Volumes/Data/Volumes/system:
Indexing disabled.
[macbook-pro]:~ $
Hopefully this is useful toward a general fix.
I'd rather avoid a custom entry for each share.