Configuring Warboy Pass-through for Virtual Machine

This section describes how to enable Warboy pass-through for a virtual machine. The example of this section is based on a specific VM tool QEMU-KVM, but it also works in other VM tools. The environment used in the example is as follows:

  • Host OS: CentOS 8

  • Guest OS: Ubuntu 20.04

  • Virtual Machine: QEMU-KVM


  • IOMMU and VT-x should be enabled in BIOS.

  • qemu-kvm, libvirt, virt-install should be installed in a host machine.

Setup Instruction

1. Enabling IOMMU in BIOS and Linux OS

First of all, you need to enable IOMMU in BIOS and Linux OS. The following command shows if IOMMU is enabled.

dmesg | grep -e DMAR -e IOMMU

You will be able to see some messages related to DMAR or IOMMU if IOMMU is enabled. If you cannot find any messages related to DMAR or IOMMU, you need to enable IOMMU in BIOS, Linux OS or both.

The ways to enable IOMMU in BIOS may depend on server or motherboard models. Please refer to the manufacturer’s manual.

You check if IOMMU is enabled in Linux OS as follows:

grep GRUB_CMDLINE_LINUX /etc/default/grub | grep iommu

If you cannot find any messages related to IOMMU, please add intel_iommu=on for Intel CPU or amd_iommu=on for AMD CPU to GRUB_CMDLINE_LINUX in /etc/default/grub and apply the changes by rebooting the machine.

If you use a legacy BIOS boot mode or UEFI boot mode, the way to enable IOMMU in Linux OS can be different.

  • Legacy BIOS boot mode: grub2-mkconfig -o /boot/grub2/grub.cfg

  • UEFI boot mode, grub2-mkconfig -o /boot/efi/EFI/{linux_distrib}/grub.cfg.

Please replace {linux_distrib} with a Linux OS name, such as centos, redhat, or ubuntu.

2. Loading vfio-pci module

Please make sure if the kernel module vfio-pci is loaded.

[root@localhost ~]# lsmod | grep vfio_pci
vfio_pci               61440  0
vfio_virqfd            16384  1 vfio_pci
vfio_iommu_type1       36864  0
vfio                   36864  2 vfio_iommu_type1,vfio_pci
irqbypass              16384  2 vfio_pci,kvm

If vfio_pci is not loaded yet, please run modprobe vfio-pci to load the module. In some OS environments, you don’t have to load vfio-pci. To make sure, please refer to the OS manual.

3. Checking if a virtual machine tool is ready

Please check if a virtual machine tool is ready to run as follows. If virt-host-validate is not found, please install the prerequisite packages described in Prerequisites

[root@localhost ~]# virt-host-validate
  QEMU: Checking for hardware virtualization                                 : PASS

  QEMU: Checking for device assignment IOMMU support                         : PASS
  QEMU: Checking if IOMMU is enabled by kernel                               : PASS

If check items are PASSED, the virtual machine tool is ready.

4. Finding Warboy’s PCIe device name

PCI BDF (Bus, Device, Function) is a unique identifier assigned to every PCIe device connected to a machine. Please find a PCI BDF of a Warboy card that you want to pass through to a virtual machine.

[root@localhost ~]# lspci -nD | grep 1ed2
0000:01:00.0 1200: 1ed2:0000 (rev 01)

1ed2 is the PCI vendor ID of FursioaAI Inc. 01:00.0 is the PCI BDF of a Warboy card in the above example. Your PCI BDF will be different according to motherboard model, server model, and PCIe slot.

Alternatively, you can use lspci -DD command to show a PCI BDF list with vendor names and find a Warboy card from the list. The vendor names depend on PCIe ID database in OS. If the database is outdated in OS, the command will show Device 1ed2:0000 instead of FuriosaAI, Inc. Warboy. You can update outdated PCIe ID database by running update-pciids in shell.

Once you find the PCIe BDB name, you can find a PCIe device name accepted by a virtual machine tool as follows:

[root@localhost ~]# virsh nodedev-list | grep pci


A PCIe device name consists of pci_ and a PCI BDF concatnated with _. In the above example, pci_0000_01_00_0 is the PCIe device name of a Warboy card.

5. Creating a virtual machine

If you reach here, you are ready to create a virtual machine with a Warboy passthrough device. Please create a virtual machine as follows.

virt-install --name ubuntu-vm \
  --os-variant ubuntu20.04 \
  --vcpus 2 \
  --memory 4096 \
  --location /var/lib/libvirt/images/ubuntu-20.04.5-live-server-amd64.iso,kernel=casper/vmlinuz,initrd=casper/initrd \
  --network bridge=br0,model=virtio \
  --disk size=50 \
  --graphics none \

Please note the option --host-device with the PCIe device name that we found in the previous step. Also, you can add more options to the command for your use cases.

In the above example, we set the guest OS image. So, it will start the guest OS installation step once the virtual machine starts. Ubuntu 20.04 or above is recommended for a guest OS. You can find recommended OS distributions for FuriosaAI SDK at Minimum requirements for SDK installation.

6. Checking the availability of a Warboy device in VM

Please make sure if the Warboy device is available on the virtual machine. lspci will shows all PCIe devices available on the virtual machine as follows.

furiosa@ubuntu-vm:~$ lspci
05:00.0 Processing accelerators: Device 1ed2:0000 (rev 01)

furiosa@ubuntu-vm:~$ sudo update-pciids

furiosa@ubuntu-vm:~$ lspci | grep Furiosa
05:00.0 Processing accelerators: FuriosaAI, Inc. Warboy (rev 01)

7. SDK installation

Once you confirm that Warboy is available in a virtual machine, please install Driver, Firmware, and Runtime Installation to install SDK and move forward next steps.