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Last updated: Apr 03, 2024

How to Use USB Devices with a VMware Virtual Machine

USB passthrough stands out as a vital feature that allows physical USB devices to be used directly in virtual machines. This capability bridges the gap between the physical and virtual worlds, enabling a wide range of USB devices—from storage drives to dongles for software licensing—to interact seamlessly with virtual environments. VMware, a leader in virtualization technology, offers robust support for USB passthrough across its product line, including VMware Workstation and ESXi. This article provides a comprehensive overview of USB passthrough in VMware virtual machines, highlighting its significance, use cases, and benefits. We'll delve into the nuts and bolts of configuring USB passthrough, from prerequisites to step-by-step implementation, ensuring you can leverage this powerful feature to its full potential. Whether you're a system administrator looking to enhance your virtual infrastructure, a developer in need of specific hardware during application testing, or simply keen on understanding the capabilities of VMware's virtualization solutions, this guide will serve as your primer to mastering USB passthrough in VMware virtual machines.

What is USB Device Passthrough?

USB device passthrough in the context of virtualization technology refers to the process of allowing a virtual machine (VM) to gain direct access to a physical USB device connected to the host system. This technique effectively "passes through" the host's USB device to a VM, making it appear as though the device is directly connected to the VM rather than the host machine. The result is that the VM can interact with the USB device as if it were running on a physical machine, with the VM's operating system handling the device drivers and management as it would in a non-virtualized environment.

This feature is particularly useful for a variety of scenarios, such as:

  • Software Development and Testing: Developers can test software that requires direct access to USB hardware, such as dongles used for software licensing or development kits for specific hardware devices.
  • Security Applications: Security appliances or software that operate with USB tokens or security keys can be virtualized while still maintaining direct access to these critical physical security devices.
  • Data Storage and Backup: Direct access to USB storage devices allows for easy data exchange between the VM and physical environments, facilitating backup and data transfer processes.
  • Specialized Hardware Use: Devices that require direct hardware access, such as USB-based laboratory instruments, medical devices, or industrial control hardware, can be used within a VM, expanding the flexibility and utility of virtualized environments.

Implementing USB passthrough involves configuring the virtualization platform (such as VMware ESXi or VMware Workstation) to recognize and assign specific USB devices to specific VMs. This process typically requires administrator privileges and may involve considerations such as USB device compatibility, VM configuration specifics, and the impact on host and VM performance. Despite these considerations, USB passthrough remains a powerful tool for enhancing the capabilities of virtual machines by bridging the gap between physical hardware and virtualized environments.

USB Device Passthrough Technology Overview and Limitations

USB device passthrough is a sophisticated feature in virtualization that extends the functionality of virtual machines (VMs) by allowing them to directly access and use USB devices connected to the host machine. This technology bridges the physical and virtual divide, offering significant advantages for users requiring specific USB devices within their VMs. However, like any technology, it comes with its own set of limitations and requirements, especially when dealing with advanced USB standards like USB 3.0.

How USB Passthrough Works

USB passthrough operates by redirecting the input and output signals of a USB device from the host machine to a VM. This redirection makes the USB device appear as if it is directly connected to the VM, allowing the guest operating system to interact with it natively. The process involves the following steps:

  • Identification: The host system identifies the connected USB device that needs to be passed through to the VM.
  • Assignment: The virtualization software (e.g., VMware) assigns the USB device to a specific VM, often requiring the user to specify which VM should access the device.
  • Redirection: The host's USB drivers are bypassed, and direct communication between the VM and the USB device is established. The VM's drivers take over the management of the device.
  • Usage: The VM uses the USB device as if it were directly connected, handling all data transfers and device operations internally.

USB 3.0 Requirements

USB 3.0 introduces higher data transfer rates, improved power management, and greater bandwidth compared to its predecessors. To effectively utilize USB 3.0 devices via passthrough, both the host system and the virtualization software must meet certain requirements:

  • Hardware Compatibility: The host machine must have USB 3.0 ports, and the motherboard should support USB 3.0 passthrough.
  • Software Support: The virtualization platform must support USB 3.0 devices. This includes having the latest versions of virtualization software and guest additions/drivers installed.
  • VM Configuration: The VM needs to be configured to support USB 3.0. This often involves adjusting VM settings to enable USB 3.0 support explicitly.

Limitations for USB Passthrough

While USB passthrough is highly beneficial, it comes with limitations that can affect its deployment and performance:

  • Performance Overhead: Passthrough can introduce performance overhead, especially for high-throughput USB 3.0 devices, due to the additional processing required to route data between the host, the VM, and the device.
  • Compatibility Issues: Not all USB devices are compatible with passthrough, and some may exhibit erratic behavior or not work at all when used in a VM.
  • USB Port Availability: Once a USB device is assigned to a VM, it becomes unavailable to the host and other VMs, potentially limiting the use of shared resources.
  • Resource Allocation: Sufficient system resources (CPU, memory, and I/O bandwidth) must be allocated to the VM to handle the demands of USB passthrough, especially for high-performance devices.

How to Connect a USB Device to a VM

Connecting a USB device to a virtual machine (VM) enables direct access to the device as if it were physically attached to the VM. This capability is crucial for various applications, including software development, data storage, and the use of specialized hardware within a virtual environment. There are multiple methods to achieve USB passthrough, but two common approaches are hardware-assisted USB passthrough and utilizing third-party solutions like USB Network Gate.

Hardware-Assisted USB Passthrough

Hardware-assisted USB passthrough leverages the virtualization platform's built-in capabilities to provide direct access to USB devices. This method is supported by major virtualization platforms like VMware ESXi and VMware Workstation. Here’s how to connect a USB device to a VM using hardware-assisted passthrough:

  • Prepare the Host System: Ensure the host system’s BIOS settings are configured to enable virtualization extensions (Intel VT-d or AMD-Vi). This is crucial for hardware-assisted passthrough to function.
  • Connect the USB Device: Physically connect the USB device to the host system.
  • Identify the Device in the Host OS: Use the host operating system or the virtualization platform's management interface to identify the connected USB device. This step is necessary to ensure the device is recognized and available for passthrough.
  • Configure the VM: Access the VM's settings through the virtualization platform's management interface. Locate the option to add or configure USB devices. Select the USB device you wish to pass through to the VM.
  • Assign the Device to the VM: Complete the configuration by assigning the identified USB device to the VM. The process may require you to specify the device by its name or identifier.
  • Verify Connection: Start or restart the VM and verify that the USB device is recognized by the guest operating system. You may need to install appropriate drivers within the guest OS if the device is not automatically recognized.

Utilizing USB Network Gate

USB Network Gate is a third-party solution that enables USB devices to be shared over a network, effectively allowing USB devices connected to one computer to be used on another, including within VMs. This method is useful for environments where direct USB passthrough is not feasible or when USB devices need to be shared among multiple VMs or over remote connections. Here’s how to use USB Network Gate for USB passthrough:

  • Install USB Network Gate: Install USB Network Gate on both the host system where the USB device is physically connected and the system hosting the VM (if different) or directly on the VM.
  • Share the USB Device: On the host system, open USB Network Gate and select the USB device you wish to share. Configure the sharing settings according to your requirements.
  • Connect to the USB Device from the VM: On the VM or on the system hosting the VM, use USB Network Gate to connect to the shared USB device. This is typically done by entering the IP address of the host system and selecting the shared device from the list.
  • Verify Connection: After connecting, verify that the USB device is accessible within the VM. Install any necessary drivers or software within the VM to ensure the device functions correctly.

VMware PCI Passthrough

VMware PCI Passthrough, also known as VMDirectPath I/O, is a feature provided by VMware's virtualization platforms, including VMware ESXi, which allows virtual machines (VMs) to directly access and control physical PCI devices connected to the host system. This technology enables VMs to utilize the full capabilities of PCI-based devices such as network interfaces, graphics cards, and storage controllers, offering near-native performance by bypassing the hypervisor layer for device access. PCI Passthrough is particularly useful for workloads that demand high rates of data throughput, low latency, or direct interface access to hardware.

How VMware PCI Passthrough Works

VMware's PCI Passthrough works by dedicating a physical PCI device on the host to a VM, allowing the VM to interact with the device without interference from the hypervisor. This is achieved through several key steps:

  • Hardware Requirements: The host system must support Intel VT-d or AMD IOMMU technology, which are hardware extensions designed to provide virtualized systems direct access to hardware devices.
  • Enablement in BIOS: VT-d or AMD IOMMU must be enabled in the host's BIOS settings. This is a crucial step as it allows the hardware to segregate device access on a per-VM basis.
  • Device Selection: The administrator selects a PCI device on the host that is to be passed through to a VM. Not all PCI devices can be used with PCI Passthrough; some devices, like those integral to the host system’s operation, cannot be dedicated to a single VM.
  • VM Configuration: The chosen PCI device is assigned to a VM through the VMware ESXi host's configuration settings. This often involves editing the VM's configuration file (.vmx) to include the PCI device or using the vSphere Client to add the device to the VM.
  • VM Direct Access: Once the VM is started, it has direct access to the PCI device. The VM's operating system will need the appropriate drivers for the device, just as if the device were connected to a physical machine.

Limitations and Considerations

  • Compatibility and Support: Not all PCI devices are compatible with PCI Passthrough. Devices that require sharing resources with the host or other VMs typically cannot be used with this feature.
  • Resource Dedication: A device dedicated to a VM through PCI Passthrough cannot be shared with other VMs or the host system. This can lead to underutilization of the device if it's not in constant use by the VM.
  • System Stability: Improper use of PCI Passthrough can affect the stability of the host system, especially if critical devices are incorrectly assigned to VMs.
  • VM Mobility: VMs with PCI Passthrough enabled lose some of the benefits of virtualization, such as the ability to migrate live VMs between hosts (vMotion), because the direct device attachment requires the VM to be tightly coupled with the physical host.

Connecting USB Smart Cards

Connecting USB smart cards to virtual machines (VMs) is a common requirement in environments where authentication, digital signatures, or secure transactions are performed. Smart cards, being a form of hardware security, offer a higher level of security compared to software-based credentials. VMware environments, among others, support USB smart card readers through USB passthrough, allowing VMs to directly interact with the smart card as if it were connected to a physical machine. This setup is crucial for scenarios such as remote work, secure access, and digital signing within a virtualized environment.

Steps to Connect USB Smart Cards to a VM

Here’s a general approach to connecting USB smart cards or their readers to VMs, particularly in VMware environments:

  1. 1. Physical Connection: Connect the USB smart card reader to the host machine. Ensure the reader is recognized by the host's operating system.

  2. 2. Enable USB Controller in VM: Before attaching the USB device, make sure the VM is configured with a USB controller. This can be done through the VM’s settings in the virtualization platform's management interface (e.g., vSphere Client for VMware). You might need to add a USB controller if one isn’t already present.

  3. 3. Connect USB Device to VM:

    • For VMware Workstation: With the VM powered on, choose the VM > Removable Devices > [Your USB Device] > Connect (Disconnect from Host). This action redirects the USB device from the host to the VM.
    • For VMware ESXi:
      • Access the vSphere Client.
      • Navigate to the VM’s settings and find the option to add a new device.
      • Select “USB Device” and choose the connected smart card reader from the list of available USB devices.
      • Confirm and apply the changes. The VM will now have the smart card reader available as if it were directly connected.
  4. 4. Install Required Drivers: Inside the VM, ensure that drivers for the USB smart card reader are installed, if not automatically recognized by the guest operating system. Similarly, any middleware necessary for the smart card itself should be installed within the VM to facilitate communication with the card.

  5. 5. Verification: Verify the connection by accessing the smart card’s contents or performing a task that requires the smart card, such as digital signing or authentication. This can usually be done through specific applications designed to work with smart cards.

Considerations and Best Practices

  • Device Compatibility: Ensure the USB smart card reader is compatible with both the host and the guest operating systems, as well as the virtualization platform.
  • Security Policies: Be aware of security policies and best practices related to smart card usage, especially if dealing with sensitive information or accessing secure systems.
  • VMware Tools: For VMware-based VMs, ensure VMware Tools is installed and up to date in the guest operating system for improved performance and compatibility.
  • Direct Path IO: For environments where USB passthrough presents challenges or is not supported, consider using DirectPath I/O to assign dedicated host USB controllers to a VM, though this approach has its own limitations and requirements.

Connecting USB smart cards to VMs is a straightforward process that extends the security benefits of smart cards to virtualized environments. Proper configuration and testing ensure that the VM can utilize the smart card for secure operations, providing an efficient solution for authentication and encryption needs in virtualized infrastructures.

Conclusion

The integration of USB and PCI passthrough technologies into VMware virtual environments showcases the incredible flexibility and potential of virtualization to mimic and extend the capabilities of physical hardware directly into virtual machines (VMs). From connecting USB smart cards for secure transactions and authentication to leveraging the full power of PCI devices for high-performance computing tasks, these features enable a wide array of use cases that were previously challenging or impossible in a virtualized context.

USB passthrough allows users to seamlessly connect USB devices—ranging from storage drives to highly secure smart card readers—directly to VMs, ensuring that applications requiring direct access to physical hardware can operate efficiently within a virtualized environment. This capability is invaluable for tasks such as software development, data protection, and secure access, where direct interaction with USB devices is essential.

Similarly, VMware's PCI Passthrough (VMDirectPath I/O) technology empowers VMs to utilize PCI devices with near-native performance, opening the door for high-throughput, low-latency tasks to be performed within VMs. This feature is particularly crucial for workloads requiring specialized hardware, such as graphics rendering or network processing, where direct access to the hardware accelerates processes and enhances performance.

However, the implementation of these passthrough technologies comes with considerations and limitations, including hardware compatibility, system stability, and the potential for underutilization of resources. The necessity for careful planning and understanding of these technologies cannot be overstated, as their improper use can lead to challenges in system configuration and performance.

FAQ

  • Can you attach a USB drive to an ESXi host?

    There are instances where you might need to grant a VM direct access to a physical device. If you have an external device with a USB interface, VMware facilitates the connection of this USB drive to a VM, whether it’s hosted on VMware Workstation or an ESXi server.

  • Is it possible to boot ESXi from a USB drive?

    Yes, you can prepare a USB flash drive for the ESXi installation or upgrade by formatting it accordingly, enabling it to boot the ESXi setup.

  • How can I make VMware recognize my USB device?

    Navigate to the VMware Workstation Pro main menu, select VM > Removable Devices > USB device > Connect (Disconnect from host), and then click OK to confirm.

  • Does VMware support USB device connections?

    Indeed, VMware allows for the virtual USB controller configuration to automatically connect USB devices to your VM when such devices are plugged into the Mac, provided the VM is running. These configurations can be applied consistently across various VMware products, including Workstation Pro and VMware Horizon 7.

  • How do I activate passthrough in VMware for a GPU device?

    To enable PCI Passthrough for a GPU device, navigate to “Configure” -> “Hardware” -> “PCI Devices” and select “Toggle Passthrough” for the GPU if it hasn’t already been activated for DirectPath I/O. Afterward, restart the host. Then, set up the VM that will utilize the GPU, ensuring to configure EFI Boot Mode under Boot Options.

  • How can I activate USB ports on a VMware virtual machine?

    Go to Window > Virtual Machine Library. Choose a virtual machine from the library and click on Settings. In the Settings menu, under Removable Devices, select USB & Bluetooth. Choose the USB device from the list, and under Advanced USB options, set the plug-in behavior for the device as needed.

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