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@ -2,7 +2,7 @@
title: Virtual Function I/O passthrough (vfio-pci)
description: Pass a physical device to a guest sysstem
published: true
date: 2025-04-02T16:07:41.270Z
date: 2025-04-02T17:16:40.166Z
tags:
editor: markdown
dateCreated: 2025-04-01T11:18:43.924Z
@ -20,7 +20,9 @@ dateCreated: 2025-04-01T11:18:43.924Z
* Make sure the GRUB has been updated after the first boot:
`# grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg`
## Collect information on the physical device to share
## How to share a physical device
### Collect information
* List IOMMU groups and their associated devices (script courtesy of the [Arch Linux wiki](https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Ensuring_that_the_groups_are_valid):
@ -70,7 +72,7 @@ In the above example, most devices are well isolated in their own IOMMU group, a
> 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.
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 |
| --- | --- | --- | --- | --- | --- |
@ -88,6 +90,8 @@ In our example, Phyllome OS is installed on the Intel SSD 660P NVMe SSD. This de
| 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.
```
@ -137,7 +141,79 @@ $ lspci
09:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a)
```
The wireless controller has been attached to bus 9 of the virtual chipset.
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 tbe 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
```
## Troubleshooting
### "Please ensure all devices within the iommu_group are bound to their vfio bus driver."
---