An Intel Graphics device can be passed to a Kata Containers container using GPU passthrough (Intel GVT-d) as well as GPU mediated passthrough (Intel GVT-g).
Intel GVT-d (one VM to one physical GPU) also named as Intel-Graphics-Device passthrough feature is one flavor of graphics virtualization approach. This flavor allows direct assignment of an entire GPU to a single user, passing the native driver capabilities through the hypervisor without any limitations.
Intel GVT-g (multiple VMs to one physical GPU) is a full GPU virtualization solution
with mediated pass-through.
A virtual GPU instance is maintained for each VM, with part of performance critical
resources, directly assigned. The ability to run a native graphics driver inside a
VM without hypervisor intervention in performance critical paths, achieves a good
balance among performance, feature, and sharing capability.
Technology | Description | Behaviour | Detail |
---|---|---|---|
Intel GVT-d | GPU passthrough | Physical GPU assigned to a single VM | Direct GPU assignment to VM without limitation |
Intel GVT-g | GPU sharing | Physical GPU shared by multiple VMs | Mediated passthrough |
- For client platforms, 5th generation Intel® Core Processor Graphics or higher are required.
- For server platforms, E3_v4 or higher Xeon Processor Graphics are required.
The following steps outline the workflow for using an Intel Graphics device with Kata.
The following configurations need to be enabled on your host kernel:
CONFIG_VFIO_IOMMU_TYPE1=m
CONFIG_VFIO=m
CONFIG_VFIO_PCI=m
CONFIG_VFIO_MDEV=m
CONFIG_VFIO_MDEV_DEVICE=m
CONFIG_DRM_I915_GVT=m
CONFIG_DRM_I915_GVT_KVMGT=m
Your host kernel needs to be booted with intel_iommu=on
on the kernel command
line.
To use this feature, you need Kata version 1.3.0 or above. Follow the Kata Containers setup instructions to install the latest version of Kata.
In order to pass a GPU to a Kata Container, you need to enable the hotplug_vfio_on_root_bus
configuration in the Kata configuration.toml
file as shown below.
$ sudo sed -i -e 's/^# *\(hotplug_vfio_on_root_bus\).*=.*$/\1 = true/g' /usr/share/defaults/kata-containers/configuration.toml
Make sure you are using the q35
machine type by verifying machine_type = "q35"
is
set in the configuration.toml
. Make sure pcie_root_port
is set to a positive value.
The default guest kernel installed with Kata Containers does not provide GPU support. To use an Intel GPU with Kata Containers, you need to build a kernel with the necessary GPU support.
The following i915 kernel config options need to be enabled:
CONFIG_DRM=y
CONFIG_DRM_I915=y
CONFIG_DRM_I915_USERPTR=y
Build the Kata Containers kernel with the previous config options, using the instructions described in Building Kata Containers kernel. For further details on building and installing guest kernels, see the developer guide.
There is an easy way to build a guest kernel that supports Intel GPU:
## Build guest kernel with ../../tools/packaging/kernel
# Prepare (download guest kernel source, generate .config)
$ ./build-kernel.sh -g intel -f setup
# Build guest kernel
$ ./build-kernel.sh -g intel build
# Install guest kernel
$ sudo -E ./build-kernel.sh -g intel install
/usr/share/kata-containers/vmlinux-intel-gpu.container -> vmlinux-5.4.15-70-intel-gpu
/usr/share/kata-containers/vmlinuz-intel-gpu.container -> vmlinuz-5.4.15-70-intel-gpu
Before using the new guest kernel, please update the kernel
parameters in configuration.toml
.
kernel = "/usr/share/kata-containers/vmlinuz-intel-gpu.container"
Use the following steps to pass an Intel Graphics device in GVT-d mode with Kata:
-
Find the Bus-Device-Function (BDF) for GPU device:
$ sudo lspci -nn -D | grep Graphics 0000:00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09)
Run the previous command to determine the BDF for the GPU device on host.
From the previous output, PCI address0000:00:02.0
is assigned to the hardware GPU device.
This BDF is used later to unbind the GPU device from the host.
"8086 1616" is the device ID of the hardware GPU device. It is used later to rebind the GPU device tovfio-pci
driver. -
Find the IOMMU group for the GPU device:
$ BDF="0000:00:02.0" $ readlink -e /sys/bus/pci/devices/$BDF/iommu_group /sys/kernel/iommu_groups/1
The previous output shows that the GPU belongs to IOMMU group 1.
-
Unbind the GPU:
$ echo $BDF | sudo tee /sys/bus/pci/devices/$BDF/driver/unbind
-
Bind the GPU to the
vfio-pci
device driver:$ sudo modprobe vfio-pci $ echo 8086 1616 | sudo tee /sys/bus/pci/drivers/vfio-pci/new_id $ echo $BDF | sudo tee --append /sys/bus/pci/drivers/vfio-pci/bind
After you run the previous commands, the GPU is bound to
vfio-pci
driver.
A new directory with the IOMMU group number is created under/dev/vfio
:$ ls -l /dev/vfio total 0 crw------- 1 root root 241, 0 May 18 15:38 1 crw-rw-rw- 1 root root 10, 196 May 18 15:37 vfio
-
Start a Kata container with GPU device:
$ sudo docker run -it --runtime=kata-runtime --rm --device /dev/vfio/1 -v /dev:/dev debian /bin/bash
Run
lspci
within the container to verify the GPU device is seen in the list of the PCI devices. Note the vendor-device id of the GPU ("8086:1616") in thelspci
output.$ lspci -nn -D 0000:00:00.0 Class [0600]: Device [8086:1237] (rev 02) 0000:00:01.0 Class [0601]: Device [8086:7000] 0000:00:01.1 Class [0101]: Device [8086:7010] 0000:00:01.3 Class [0680]: Device [8086:7113] (rev 03) 0000:00:02.0 Class [0604]: Device [1b36:0001] 0000:00:03.0 Class [0780]: Device [1af4:1003] 0000:00:04.0 Class [0100]: Device [1af4:1004] 0000:00:05.0 Class [0002]: Device [1af4:1009] 0000:00:06.0 Class [0200]: Device [1af4:1000] 0000:00:0f.0 Class [0300]: Device [8086:1616] (rev 09)
Additionally, you can access the device node for the graphics device:
$ ls /dev/dri card0 renderD128
For GVT-g, you append i915.enable_gvt=1
in addition to intel_iommu=on
on your host kernel command line and then reboot your host.
Use the following steps to pass an Intel Graphics device in GVT-g mode to a Kata Container:
-
Find the BDF for GPU device:
$ sudo lspci -nn -D | grep Graphics 0000:00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09)
Run the previous command to find out the BDF for the GPU device on host. The previous output shows PCI address "0000:00:02.0" is assigned to the GPU device.
-
Choose the MDEV (Mediated Device) type for VGPU (Virtual GPU):
For background on
mdev
types, please follow this kernel documentation.-
List out the
mdev
types for the VGPU:$ BDF="0000:00:02.0" $ ls /sys/devices/pci0000:00/$BDF/mdev_supported_types i915-GVTg_V4_1 i915-GVTg_V4_2 i915-GVTg_V4_4 i915-GVTg_V4_8
-
Inspect the
mdev
types and choose one that fits your requirement:$ cd /sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types/i915-GVTg_V4_8 && ls available_instances create description device_api devices $ cat description low_gm_size: 64MB high_gm_size: 384MB fence: 4 resolution: 1024x768 weight: 2 $ cat available_instances 7
The output of file
description
represents the GPU resources that are assigned to the VGPU with specified MDEV type.The output of fileavailable_instances
represents the remaining amount of VGPUs you can create with specified MDEV type.
-
-
Create a VGPU:
-
Generate a UUID:
$ gpu_uuid=$(uuid)
-
Write the UUID to the
create
file under the chosenmdev
type:$ echo $(gpu_uuid) | sudo tee /sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types/i915-GVTg_V4_8/create
-
-
Find the IOMMU group for the VGPU:
$ ls -la /sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types/i915-GVTg_V4_8/devices/${gpu_uuid}/iommu_group lrwxrwxrwx 1 root root 0 May 18 14:35 devices/bbc4aafe-5807-11e8-a43e-03533cceae7d/iommu_group -> ../../../../kernel/iommu_groups/0 $ ls -l /dev/vfio total 0 crw------- 1 root root 241, 0 May 18 11:30 0 crw-rw-rw- 1 root root 10, 196 May 18 11:29 vfio
The IOMMU group "0" is created from the previous output.
Now you can use the device node/dev/vfio/0
in docker command line to pass the VGPU to a Kata Container. -
Start Kata container with GPU device enabled:
$ sudo docker run -it --runtime=kata-runtime --rm --device /dev/vfio/0 -v /dev:/dev debian /bin/bash $ lspci -nn -D 0000:00:00.0 Class [0600]: Device [8086:1237] (rev 02) 0000:00:01.0 Class [0601]: Device [8086:7000] 0000:00:01.1 Class [0101]: Device [8086:7010] 0000:00:01.3 Class [0680]: Device [8086:7113] (rev 03) 0000:00:02.0 Class [0604]: Device [1b36:0001] 0000:00:03.0 Class [0780]: Device [1af4:1003] 0000:00:04.0 Class [0100]: Device [1af4:1004] 0000:00:05.0 Class [0002]: Device [1af4:1009] 0000:00:06.0 Class [0200]: Device [1af4:1000] 0000:00:0f.0 Class [0300]: Device [8086:1616] (rev 09)
BDF "0000:00:0f.0" is assigned to the VGPU device.
Additionally, you can access the device node for the graphics device:
$ ls /dev/dri card0 renderD128