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title: Virtual Function I/O Mediated devices (vfio-mdev)
description: Create and Configure Virtual Function I/O Mediated devices (vfio-mdev)
published: true
date: 2023-05-14T20:10:36.548Z
date: 2025-03-31T14:19:04.753Z
tags:
editor: markdown
dateCreated: 2022-07-21T21:10:41.046Z
---
# Configure *vfio-mdev*
# *vfio-mdev* configuration
> These instructions only cover **Intel GPUs** that are compatible with *vfio-mdev* (5th to 10th generation). Since generation 11th, *vfio-mdev* has been superseded by *SR-IOV*.
{.is-warning}
GPUs compatible with [Virtual Function I/O Mediated devices](https://www.kernel.org/doc/html/latest/driver-api/vfio-mediated-device.html) (vfio-mdev) can be split into multiple virtual GPUs (vGPUs).
Then, these vGPUs can be assigned to virtual machines or containers.
[Virtual Function I/O Mediated devices](https://www.kernel.org/doc/html/latest/driver-api/vfio-mediated-device.html) (vfio-mdev) allows a phyiscal GPU to be split into multiple virtual GPUs (vGPU). Such a vGPU can then be assigned to a virtual machine or a container.
Contrary to paravirtualized GPUs (e.g. *virtio-gpu*), vGPUs can use the same driver as their parent GPU (e.g. a guest compatible with an Intel GPUs will be able to leverage an Intel-based vGPUs)
## Modify the system allocated to the GPU in the BIOS/UEFI
> Some computers allow you to modify the system memory allocated or shared with the integrated GPU, which may allow you to create more vGPUs.
{.is-info}
> For Intel integrated graphics cards only; rarely available on laptops computers.
{.is-warning}
* Before the host operating system boots up, you need to enter the BIOS/UEFI and to look for a setting called *GPU aperture size*, or *GPU shared memory*.
* Use the highest possible value.
> System memory will be reserved for the GPU, so make sure you have enough system memory to accomodate both the GPU and your operating system.
{.is-warning}
## Preparation
* Make sure the GRUB has been updated after [the first boot](https://wiki.phyllo.me/getstarted/disk#update-grub-and-reboot)
* [Install](/deploy/install) the *Phyllome OS Desktop II*
* Make sure the GRUB has been updated after the first boot: `# grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg`
## Procedure
### Create a virtual GPU
List available GPUs using the `mdevctl` software:
List all available vGPUs types:
```
mdevctl types
$ mdevctl types
```
```
@ -68,11 +53,10 @@ mdevctl types
Description: low_gm_size: 64MB, high_gm_size: 384MB, fence: 4, resolution: 1024x768, weight: 2
```
> Increasing the memory allocated to the GPU in the BIOS/EFI may increase the number and kind of available instances.
> Allocating more memory to the GPU in the platform firmware may increase the number of vGPUs one can create. See [Troubleshooting](#Troubleshooting) section below.
{.is-info}
In this case, the `i915-GVTg_V5_4` kind seems to offer the best trade-offs between the available resolution and the number of available instances.
In the example above, the `i915-GVTg_V5_4` virtual type seems to offer the best trade-offs between the available resolution and the number of available instances.
* Generate a universally unique identifier (UUID) with the following command:
@ -156,24 +140,18 @@ mdevctl list -d
* Then starts the domain
## Configure Spice / SDL
*To-do*
## Troubleshooting
### No or low number of available instances
### Low number of available vGPU instances
Increasing the memory allocated to the GPU (a.k.a. the GPU aperture size) may increase the number of available instances.
On some computers, it is possible to increase the system memory allocated to the integrated GPU. By doing so, you may be able to create more vGPUs.
Some computers allow you to modify the memory allocated or shared with the integrated GPU, which may allow you to create more vGPUs.
* Before the host operating system boots up, enter the BIOS/UEFI and look for a setting called *GPU aperture size* or *GPU shared memory*
* Before the host operating system boots up, enter the BIOS/UEFI and look for a setting called *GPU aperture size*, or *GPU shared memory*.
* Use the highest possible value, but not higher than the available system memory.
* Use the highest possible value.
> The memory will be reserved to the GPU, so make sure you have enough leftover memory to accomodate both the GPU and your operating system.
{.is-info}
> System memory will be reserved for the GPU, so make sure you have enough system memory to accomodate both the GPU and your operating system. For instance, if you have a total of 16GB of system memory, it is recommanded to not allocate more than 4GB to the GPU.
{.is-warning}
## Resources