Am I screwed if both my GPUs are in the same IOMMU group? (Aorus X570 Master)

YES! Dude I love you!

I thought I would enable these options one by one and check the difference. SVM and IOMMU I already had enabled, so I enabled ACS and immediately my IOMMU group count exploded. I now have 44 separate IOMMU groups rather than 20. Even the audio card and GPU of my Radeon video card is in 2 separate IOMMU groups :laughing:

But most importantly:

IOMMU Group 32:
	0c:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP106 [GeForce GTX 1060 3GB] [10de:1c02] (rev a1)
	0c:00.1 Audio device [0403]: NVIDIA Corporation GP106 High Definition Audio Controller [10de:10f1] (rev a1)

I did not touch the “Enable AER cap” or “Alternative routing” options, for the record.

Here is the new full IOMMU output for those who are interested
IOMMU Group 0:
	00:01.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 1:
	00:01.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge [1022:1483]
IOMMU Group 10:
	00:07.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B] [1022:1484]
IOMMU Group 11:
	00:08.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 12:
	00:08.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B] [1022:1484]
IOMMU Group 13:
	00:08.2 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B] [1022:1484]
IOMMU Group 14:
	00:08.3 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Internal PCIe GPP Bridge 0 to bus[E:B] [1022:1484]
IOMMU Group 15:
	00:14.0 SMBus [0c05]: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller [1022:790b] (rev 61)
	00:14.3 ISA bridge [0601]: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge [1022:790e] (rev 51)
IOMMU Group 16:
	00:18.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 0 [1022:1440]
	00:18.1 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 1 [1022:1441]
	00:18.2 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 2 [1022:1442]
	00:18.3 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 3 [1022:1443]
	00:18.4 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 4 [1022:1444]
	00:18.5 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 5 [1022:1445]
	00:18.6 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 6 [1022:1446]
	00:18.7 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Matisse Device 24: Function 7 [1022:1447]
IOMMU Group 17:
	01:00.0 Non-Volatile memory controller [0108]: Phison Electronics Corporation E12 NVMe Controller [1987:5012] (rev 01)
IOMMU Group 18:
	02:00.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse Switch Upstream [1022:57ad]
IOMMU Group 19:
	03:00.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a3]
IOMMU Group 2:
	00:01.2 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge [1022:1483]
IOMMU Group 20:
	03:01.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a3]
IOMMU Group 21:
	03:03.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a3]
IOMMU Group 22:
	03:04.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a3]
IOMMU Group 23:
	03:05.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a3]
IOMMU Group 24:
	03:08.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a4]
	09:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Reserved SPP [1022:1485]
	09:00.1 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller [1022:149c]
	09:00.3 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller [1022:149c]
IOMMU Group 25:
	03:09.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a4]
	0a:00.0 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
IOMMU Group 26:
	03:0a.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Matisse PCIe GPP Bridge [1022:57a4]
	0b:00.0 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
IOMMU Group 27:
	04:00.0 Non-Volatile memory controller [0108]: Phison Electronics Corporation E12 NVMe Controller [1987:5012] (rev 01)
IOMMU Group 28:
	05:00.0 Non-Volatile memory controller [0108]: Phison Electronics Corporation E12 NVMe Controller [1987:5012] (rev 01)
IOMMU Group 29:
	06:00.0 Network controller [0280]: Intel Corporation Wi-Fi 6 AX200 [8086:2723] (rev 1a)
IOMMU Group 3:
	00:02.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 30:
	07:00.0 Ethernet controller [0200]: Intel Corporation I211 Gigabit Network Connection [8086:1539] (rev 03)
IOMMU Group 31:
	08:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 01)
IOMMU Group 32:
	0c:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP106 [GeForce GTX 1060 3GB] [10de:1c02] (rev a1)
	0c:00.1 Audio device [0403]: NVIDIA Corporation GP106 High Definition Audio Controller [10de:10f1] (rev a1)
IOMMU Group 33:
	0d:00.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Upstream Port of PCI Express Switch [1002:1478] (rev c1)
IOMMU Group 34:
	0e:00.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 XL Downstream Port of PCI Express Switch [1002:1479]
IOMMU Group 35:
	0f:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 [Radeon RX 5600 OEM/5600 XT / 5700/5700 XT] [1002:731f] (rev c1)
IOMMU Group 36:
	0f:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 10 HDMI Audio [1002:ab38]
IOMMU Group 37:
	10:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Function [1022:148a]
IOMMU Group 38:
	11:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Reserved SPP [1022:1485]
IOMMU Group 39:
	11:00.1 Encryption controller [1080]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse Cryptographic Coprocessor PSPCPP [1022:1486]
IOMMU Group 4:
	00:03.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 40:
	11:00.3 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] Matisse USB 3.0 Host Controller [1022:149c]
IOMMU Group 41:
	11:00.4 Audio device [0403]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse HD Audio Controller [1022:1487]
IOMMU Group 42:
	12:00.0 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
IOMMU Group 43:
	13:00.0 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
IOMMU Group 5:
	00:03.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge [1022:1483]
IOMMU Group 6:
	00:03.2 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse GPP Bridge [1022:1483]
IOMMU Group 7:
	00:04.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 8:
	00:05.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]
IOMMU Group 9:
	00:07.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Starship/Matisse PCIe Dummy Host Bridge [1022:1482]

While I was at it I decided to do a little science. I found the AER Cap and Alternate Routing options. (The latter was tricky because the option is called “PCIe ARI Support”, and “Alternate Routing” isn’t mentioned unless you read the option description.)

Both these options were set to “Auto” by default. I tried setting both options to “Enabled” and “Disabled” separately, and I can report that neither made any difference to the show-iommu.sh script output. (The output had the same MD5 sum after every change.)