Is there a way to tell what iommu group an empty pci-e slot is in?

Software & Operating Systems VFIO
1

What the subject says.

The obvious way to tell would be to stick something in every slot, or move the same card between slots, checking your groups each time, and mapping it out that way. But I just hurt my shoulder today, so physically moving around enough to do that is not in the cards.

So is there a way to tell via Linux Command line?

I’m working through some search results, but haven’t found anything that answers my question. Just lots of “this is what iommu is”, “here’s how to use lscpi”, and so on.

I’m using a bash script (I think from the pass through Arch wiki article) to check my groups.

#!/bin/bash
shopt -s nullglob
for g in /sys/kernel/iommu_groups/*; do
    echo "IOMMU Group ${g##*/}:"
    for d in $g/devices/*; do
        echo -e "\t$(lspci -nns ${d##*/})"
    done;
done;

I’m running Pop!_OS 18.04. An ASUS PRIME X399-A motherboard.

My goal is to get a SAS card passed through to my virtualized FreeNAS. I’ve used up all my motherboard sata ports…

I already have passed through a GPU and USB card to a W10 vm. So I know IOMMU is working. But
I initially wanted to put the USB card in the 1x or 4x pci-e slots, but whichever one I tried was grouped with something I didn’t want to pass through (can’t remember what it was…) Which means at least some of my slots are not grouped in a manner conducive to pass through.

Anyway, thanks in advance for any tips.