About a month back I had received an interesting tidbit from Darius Davis (VMware Engineer) after helping a customer solve an interesting problem and Darius thought this could be a useful blog post to share. Funny enough, a couple of weeks after that conversation, a simliar issue was being faced by another customer and luckily I was able to share with them the solution and also validate the specific configuration that was needed.

The customer that Darius was helping out had two VMs running on ESXi which they wanted to configure several passthrough devices. In addition to a PCI passthrough of a GPU, they also wanted to passthrough independent USB keyboard and mouse to each individual VM. PCI passthrough to a VM is nothing new but passing through a USB keyboard/mouse also known as Human Interface Devices (HID) to a VM is generally not expected. The physical ESXi host just assumes these type of USB devices are meant for it to consume.

In addition to HID USB devices, there are also Chip Card Interface Devices (CCID) USB devices like a smart card reader which customers may also want to passthrough to a VM. The latter use case was what I ended up helping the customer out with. To passthrough HID/CCID USB devices, the following steps are required which will include changes to the ESXi host.

Step 1 - Add the following two VM Advanced Settings for all USB CCID/HID devices that you wish to enable passthrough:

HID USB Devices:

usb.generic.allowHID = "TRUE"
usb.quirks.device0 = "0xXXXX:0xYYYY allow"

CCID USB Devices:

usb.generic.allowCCID = "TRUE"
usb.quirks.device0 = "0xXXXX:0xYYYY allow"

where 0xXXXX = vendorId and 0xYYYY = deviceId (e.g 0x03f0:0x0024) which was retrieved from the previous step

To list all USB devices and get their vendor and device ID, you can use the lsusb command found within the ESXi Shell and below is an example listing out both my USB Mouse and Keyboard.

Step 2 - We need to make the USB arbitrator service aware of these USB device quirks by adding the usb.quirks.deviceN string to /etc/vmware/config file. In my example above, I want to enable passthrough for both my Mouse and Keyboard device, so the following entries would be appended:

usb.quirks.device0 = "0x05fe:0x0011 allow"
usb.quirks.device1 = "0x046d:0xc31d allow"

Step 3 - Lastly, we need to add the following string to the ESXi boot option to disable the VMkernel from claiming HID USB devices.

CONFIG./USB/quirks=0xXXXX:0xYYYY::0xffff:UQ_KBD_IGNORE

where 0xXXXX = vendorId and 0xYYYY = deviceId (e.g 0x03f0:0x0024)

The easiest way to append this to the boot option is by editing /bootbank/boot.cfg rather than manually typing this during the initial boot up (SHIFT+O)

Note: This is not required for CCID devices or mouse devices as they are not claimed by ESXi

Step 4 - A system reboot of your ESXi host will be required for the changes to go into effect. Once your ESXi host is available, you can use the vSphere H5 Client or Embedded ESXi Host Client to attach the USB devices. For vCenter Server, click on "Add New Device" and select "Host USB Device" and for ESXi, click on "Add other device" and select "USB Device".