wiki/gofurther/vfio-pci.md

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title	description	published	date	tags	editor	dateCreated
Virtual Function I/O passthrough (vfio-pci)	Pass a physical device to a guest sysstem	true	2025-04-02T18:18:52.594Z		markdown	2025-04-01T11:18:43.924Z

Vfio-pci configuration

Virtual Function I/O (vfio-pci) passthrough allows for a single physical device to be assigned to a virtual machine or container.

Preparation

• Install any version of Phyllome OS

• Make sure the GRUB has been updated after the first boot: # grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

How to share a physical device

Collect information

• List IOMMU groups and their associated devices (script courtesy of the Arch Linux wiki:

$ shopt -s nullglob
for g in $(find /sys/kernel/iommu_groups/* -maxdepth 0 -type d | sort -V); do
    echo "IOMMU Group ${g##*/}:"
    for d in $g/devices/*; do
        echo -e "\t$(lspci -nns ${d##*/})"
    done;
done;

IOMMU Group 0:
	00:02.0 VGA compatible controller [0300]: Intel Corporation Iris Pro Graphics 580 [8086:193b] (rev 09)
IOMMU Group 1:
	00:00.0 Host bridge [0600]: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Host Bridge/DRAM Registers [8086:1910] (rev 0a)
IOMMU Group 2:
	00:08.0 System peripheral [0880]: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model [8086:1911]
IOMMU Group 3:
	00:14.0 USB controller [0c03]: Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller [8086:a12f] (rev 31)
	00:14.2 Signal processing controller [1180]: Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem [8086:a131] (rev 31)
IOMMU Group 4:
	00:16.0 Communication controller [0780]: Intel Corporation 100 Series/C230 Series Chipset Family MEI Controller #1 [8086:a13a] (rev 31)
IOMMU Group 5:
	00:1c.0 PCI bridge [0604]: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #1 [8086:a110] (rev f1)
[...]
IOMMU Group 11:
	00:1f.0 ISA bridge [0601]: Intel Corporation HM170 Chipset LPC/eSPI Controller [8086:a14e] (rev 31)
	00:1f.2 Memory controller [0580]: Intel Corporation 100 Series/C230 Series Chipset Family Power Management Controller [8086:a121] (rev 31)
	00:1f.3 Audio device [0403]: Intel Corporation 100 Series/C230 Series Chipset Family HD Audio Controller [8086:a170] (rev 31)
	00:1f.4 SMBus [0c05]: Intel Corporation 100 Series/C230 Series Chipset Family SMBus [8086:a123] (rev 31)
IOMMU Group 12:
	00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection (2) I219-LM [8086:15b7] (rev 31)
IOMMU Group 13:
	02:00.0 SD Host controller [0805]: O2 Micro, Inc. SD/MMC Card Reader Controller [1217:8621] (rev 01)
IOMMU Group 14:
	03:00.0 Network controller [0280]: Intel Corporation Wireless 8260 [8086:24f3] (rev 3a)
IOMMU Group 15:
	3d:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd NVMe SSD Controller SM951/PM951 [144d:a802] (rev 01)
IOMMU Group 16:
	3e:00.0 Non-Volatile memory controller [0108]: Intel Corporation SSD 660P Series [8086:f1a8] (rev 03)
[...]

In the above example, most devices are well isolated in their own IOMMU group, at the exception to the USB controller and the HD audio controller.

In general, but not always, devices associated to a particular IOMMU group have to be passed through a guest system together {.is-info}

In our example, Phyllome OS is installed on the Intel SSD 660P NVMe SSD. This device should not be shared with a guest system.

IOMMU Group	Bus	Slot	Function	Device	ID
0	0x00	0x02	0x0	Intel Corporation Iris Pro Graphics 580	8086:193b
2	0x00	0x08	0x0	Intel Gaussian Mixture Model - Neural Network Accelerator	8086:1911
3	0x00	0x14	0x0	USB 3.0 xHCI Controller	8086:a12f
3	0x00	0x14	0x2	Thermal Subsystem	8086:a131
4	0x00	0x16	0x0	MEI Controller	8086:a13a
11	0x00	0x1f	0x0	M170 Chipset LPC/eSPI Controller	8086:a14e
11	0x00	0x1f	0x2	Power Management Controller	8086:a121
11	0x00	0x1f	0x3	HD Audio Controller	8086:a170
11	0x00	0x1f	0x4	SMBus	8086:a123
12	0x00	0x1f	0x4	Ethernet Connection I219-LM	8086:15b7
13	0x02	0x00	0x0	SD/MMC Card Reader Controller	1217:8621
14	0x03	0x00	0x0	Intel Corporation Wireless 8260	8086:24f3
15	0x3d	0x00	0x0	NVMe SSD Controller SM951/PM951	144d:a802

Example 1: share a wireless controller

Let's focus on sharing the wireless controller, which is conveniently located on a IOMMU group of its own.

IOMMU Group 14:
	03:00.0 Network controller [0280]: Intel Corporation Wireless 8260 [8086:24f3] (rev 3a)

The first digits corresponds to the bus, slot and function associated to the device.

IOMMU Group	Bus	Slot	Function	Device	ID
14	0x03	0x00	0x0	Intel Corporation Wireless 8260	8086:24f3

In order to share such wireless card with a guest, edit the XML file associated to the domain and add the following:

<domain type="kvm">
[...]
	<devices>
[...]
		<hostdev mode="subsystem" type="pci" managed="yes">
  		<source>
    		<address domain="0x0000" bus="0x00" slot="0x14" function="0x0"/>
  		</source>
		</hostdev>
[...]
	</devices>
[...]
</domain>

• Start the domain and have a look inside the guest system that has the physical devices attached to it:

$ lspci

00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller
00:01.0 VGA compatible controller: Red Hat, Inc. Virtio 1.0 GPU (rev 01)
00:02.0 PCI bridge: Red Hat, Inc. QEMU PCIe Root port
[...]
00:1f.0 ISA bridge: Intel Corporation 82801IB (ICH9) LPC Interface Controller (rev 02)
00:1f.2 SATA controller: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 port SATA Controller [AHCI mode] (rev 02)
[...]
09:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a)
0a:00.0 SD Host controller: O2 Micro, Inc. SD/MMC Card Reader Controller (rev 01)
0b:00.0 PCI bridge: Red Hat, Inc. Device 000e
09:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a)

The wireless controller has been successfully attached to bus 9 of the virtual chipset.

Example 2: share the USB controller

Let's try to share the USB controller, which is in the same IOMMU group as the Thermal Subsystem.

IOMMU Group 3:
	00:14.0 USB controller [0c03]: Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller [8086:a12f] (rev 31)
	00:14.2 Signal processing controller [1180]: Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem [8086:a131] (rev 31)

IOMMU Group	Bus	Slot	Function	Device	ID
3	0x00	0x14	0x0	USB 3.0 xHCI Controller	8086:a12f
3	0x00	0x14	0x2	Thermal Subsystem	8086:a131

The two devices has to be shared with the guest at the same time. Edit the XML file associated to the domain and add the following:

<domain type="kvm">
[...]
	<devices>
[...]
    <hostdev mode="subsystem" type="pci" managed="yes">
      <source>
        <address domain="0x0000" bus="0x00" slot="0x14" function="0x0"/>
      </source>
    </hostdev>
    <hostdev mode="subsystem" type="pci" managed="yes">
      <source>
        <address domain="0x0000" bus="0x00" slot="0x14" function="0x2"/>
      </source>
    </hostdev>
 
[...]
	</devices>
[...]
</domain>

• Start the domain and have a look inside the guest system that has the physical devices attached to it:

$ lspci

00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller
[...]
0b:00.0 PCI bridge: Red Hat, Inc. Device 000e
0c:03.0 USB controller: Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller (rev 31)
0c:04.0 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem (rev 31)

The USB controller and the Thermal Subsystem has been successfully attached to the domain.

• All devices attached to physical USB ports will be automatically shared with the guest system

$ lsusb

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 003: ID 8087:0a2b Intel Corp. Bluetooth wireless interface
Bus 001 Device 004: ID 046d:c077 Logitech, Inc. Mouse
Bus 001 Device 005: ID 046d:c31c Logitech, Inc. Keyboard K120
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub

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