#!/bin/bash
shopt -s nullglob
for d in /sys/kernel/iommu_groups/*/devices/*; do
    n=${d#*/iommu_groups/*}; n=${n%%/*}

    if [ "$n" != "$prev" ] ; then
            echo "IOMMU Group $n"
    fi
    echo -ne "\t"
    lspci -nns "${d##*/}"

    #printf 'IOMMU Group %s ' "$n"
    #lspci -nns "${d##*/}"

    prev=$n
done;