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PCI Passthrough

PCI passthrough gives a virtual machine direct access to a PCIe device installed in the server, such as a GPU, network adapter, or storage controller. The device is detached from the host and presented to the VM with near-native performance.

PCI passthrough requires IOMMU (Intel VT-d or AMD-Vi) to be enabled in the server's BIOS.

Enable a PCI Device​

Mark a PCI device as available for passthrough. This is a hypervisor-level operation — no VM needs to be involved.

  1. Navigate to the hypervisor's detail page in the Gallium Console.
  2. Select the Passthrough tab.
  3. Under PCI Devices, find the device you want to enable.
  4. Click Enable.

The device is detached from the host and becomes available to attach to a VM.

warning

Enabling a PCI device enables all devices in the same IOMMU group. Review the group membership shown in the Console before enabling to ensure you are not detaching devices the host depends on.

Add to a VM​

Attach an enabled PCI device to a virtual machine. The VM must be stopped.

  1. Navigate to the VM's detail page.
  2. Select the Hardware tab.
  3. Under Passthrough Devices, click Add Device.
  4. Select the PCI device from the list of available devices.
  5. Click Add.

The device will be available to the VM the next time it starts.

Remove from a VM​

Detach a PCI device from a virtual machine. The VM must be stopped.

  1. Navigate to the VM's detail page.
  2. Select the Hardware tab.
  3. Under Passthrough Devices, find the device you want to remove.
  4. Click Remove.
  5. Confirm the removal.

The device returns to the list of available passthrough devices and can be assigned to another VM.

Disable a PCI Device​

Return a PCI device to host use. The device must not be assigned to any VM.

  1. Navigate to the hypervisor's detail page.
  2. Select the Passthrough tab.
  3. Under PCI Devices, find the device you want to disable.
  4. Click Disable.

The device is reattached to the host and is no longer available for passthrough.

info

Disabling a PCI device also disables all other devices in the same IOMMU group.

Troubleshooting​

Large VRAM GPUs do not start​

There is a known issue with some GPUs with more then 32GB of VRAM that will attach to a VM but fail to initialise. Please contact support for a workaround.