house ~ # dmesg | grep -i iommu
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.17.0-gentoo root=/dev/nvme0n1p4 ro pcie_aspm=off mem_encrypt=off amd_iommu=on
[    0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-4.17.0-gentoo root=/dev/nvme0n1p4 ro pcie_aspm=off mem_encrypt=off amd_iommu=on
[    0.477413] AMD-Vi: IOMMU performance counters supported
[    0.477466] AMD-Vi: IOMMU performance counters supported
[    0.477957] iommu: Adding device 0000:00:01.0 to group 0
[    0.478225] iommu: Adding device 0000:00:01.1 to group 1
[    0.478455] iommu: Adding device 0000:00:01.2 to group 2
[    0.478711] iommu: Adding device 0000:00:02.0 to group 3
[    0.478950] iommu: Adding device 0000:00:03.0 to group 4
[    0.479223] iommu: Adding device 0000:00:03.1 to group 5
[    0.479471] iommu: Adding device 0000:00:04.0 to group 6
[    0.479735] iommu: Adding device 0000:00:07.0 to group 7
[    0.479750] iommu: Adding device 0000:00:07.1 to group 7
[    0.480004] iommu: Adding device 0000:00:08.0 to group 8
[    0.480022] iommu: Adding device 0000:00:08.1 to group 8
[    0.480308] iommu: Adding device 0000:00:14.0 to group 9
[    0.480323] iommu: Adding device 0000:00:14.3 to group 9
[    0.480578] iommu: Adding device 0000:00:18.0 to group 10
[    0.480592] iommu: Adding device 0000:00:18.1 to group 10
[    0.480606] iommu: Adding device 0000:00:18.2 to group 10
[    0.480620] iommu: Adding device 0000:00:18.3 to group 10
[    0.480634] iommu: Adding device 0000:00:18.4 to group 10
[    0.480648] iommu: Adding device 0000:00:18.5 to group 10
[    0.480661] iommu: Adding device 0000:00:18.6 to group 10
[    0.480677] iommu: Adding device 0000:00:18.7 to group 10
[    0.480959] iommu: Adding device 0000:00:19.0 to group 11
[    0.480974] iommu: Adding device 0000:00:19.1 to group 11
[    0.480989] iommu: Adding device 0000:00:19.2 to group 11
[    0.481004] iommu: Adding device 0000:00:19.3 to group 11
[    0.481018] iommu: Adding device 0000:00:19.4 to group 11
[    0.481032] iommu: Adding device 0000:00:19.5 to group 11
[    0.481047] iommu: Adding device 0000:00:19.6 to group 11
[    0.481061] iommu: Adding device 0000:00:19.7 to group 11
[    0.481320] iommu: Adding device 0000:01:00.0 to group 12
[    0.481342] iommu: Adding device 0000:01:00.1 to group 12
[    0.481363] iommu: Adding device 0000:01:00.2 to group 12
[    0.481374] iommu: Adding device 0000:02:00.0 to group 12
[    0.481386] iommu: Adding device 0000:02:02.0 to group 12
[    0.481399] iommu: Adding device 0000:02:03.0 to group 12
[    0.481411] iommu: Adding device 0000:02:04.0 to group 12
[    0.481427] iommu: Adding device 0000:03:00.0 to group 12
[    0.481448] iommu: Adding device 0000:04:00.0 to group 12
[    0.481462] iommu: Adding device 0000:05:00.0 to group 12
[    0.481476] iommu: Adding device 0000:06:00.0 to group 12
[    0.481493] iommu: Adding device 0000:06:00.1 to group 12
[    0.481726] iommu: Adding device 0000:07:00.0 to group 13
[    0.481964] iommu: Adding device 0000:08:00.0 to group 14
[    0.481986] iommu: Adding device 0000:08:00.1 to group 14
[    0.481997] iommu: Adding device 0000:09:00.0 to group 7
[    0.482007] iommu: Adding device 0000:09:00.2 to group 7
[    0.482017] iommu: Adding device 0000:09:00.3 to group 7
[    0.482029] iommu: Adding device 0000:0a:00.0 to group 8
[    0.482039] iommu: Adding device 0000:0a:00.2 to group 8
[    0.482049] iommu: Adding device 0000:0a:00.3 to group 8
[    0.482271] iommu: Adding device 0000:40:01.0 to group 15
[    0.482512] iommu: Adding device 0000:40:02.0 to group 16
[    0.482741] iommu: Adding device 0000:40:03.0 to group 17
[    0.482988] iommu: Adding device 0000:40:03.1 to group 18
[    0.483239] iommu: Adding device 0000:40:04.0 to group 19
[    0.483454] iommu: Adding device 0000:40:07.0 to group 20
[    0.483475] iommu: Adding device 0000:40:07.1 to group 20
[    0.483693] iommu: Adding device 0000:40:08.0 to group 21
[    0.483713] iommu: Adding device 0000:40:08.1 to group 21
[    0.484004] iommu: Adding device 0000:41:00.0 to group 22
[    0.484033] iommu: Adding device 0000:41:00.1 to group 22
[    0.484045] iommu: Adding device 0000:42:00.0 to group 20
[    0.484055] iommu: Adding device 0000:42:00.2 to group 20
[    0.484065] iommu: Adding device 0000:42:00.3 to group 20
[    0.484075] iommu: Adding device 0000:43:00.0 to group 21
[    0.484085] iommu: Adding device 0000:43:00.2 to group 21
[    0.484241] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
[    0.484247] AMD-Vi: Found IOMMU at 0000:40:00.2 cap 0x40
[    0.485544] perf/amd_iommu: Detected AMD IOMMU #0 (2 banks, 4 counters/bank).
[    0.485552] perf/amd_iommu: Detected AMD IOMMU #1 (2 banks, 4 counters/bank).
house ~ #