Introduction

Have you ever found yourself thinking "gee I wish I could hotplug my keyboard between a qemu guest and my host system, all at the press of a button!"

Sound familiar? Well buckle up, bucko! We're plunging straight into golang and racing towards that exact goal.

...Why?

Like most computery stuff that I do, I am mostly doing this out of curiosity. I wanted to give Go a try, and I have a use case (VFIO-powered Windows gaming virtual machine). If someone else out there uses this too, terrific!

INSTALLING

None of this is automatic or pretty. You have been warned.

Generating a private key

Commands issued to kbserver are encrypted with 256-bit AES. kbclient checks the directory from which it was executed for private.key, unless you specify -key=path/to/private.key. To generate this file, run keyutil with no arguments. This will generate a (pseudo)random key and stick it in private.key.

Installing Client

Windows

• Put kbclient.exe somewhere on your filesystem
• Create a shortcut to kbclient.exe
• Configure the shortcut path to be "X:\path\to\kbclient.exe" -detach -key=X:\path\to\private.key
• Configure a hotkey combo for the shortcut (I like Ctrl+Alt+Scroll Lock as it also makes the scroll lock inicator somewhat useful)

Linux

• Put kbclient somewhere on your filesystem
• Configure a hotkey combo to run /path/to/kbclient -attach -key=/path/to/private.key (How you do this depends on your choice of DE but I assume if you've made it as far as needing something like this you've got that shit under control)
  • I suggest using the same hotkey combo for Windows and Linux both

config.json

Specify the hostname/IP and port number where kbserver is listening. kbclient will attempt to load config.json from the current working directory, or it will try to load the file specified by -config=/path/to/config.json

Sample:

{
    "ManagementPort":"7357",
    "ManagementHost":"192.168.0.13"
}

Configuring QEMU

You must add a new monitor to your qemu invocation:

qemu ... -chardev socket,id=mon2,*host=localhost,port=4445*,server,nowait -mon chardev=mon2,mode=readline

Note: unless you want any joker to be able to connect to and control your guest, don't bind this to a different interface. In fact, it should really be a local socket, but I don't support that yet.

Installing Linux Server

Nothing much to this yet; just run ./kbserver. This will attempt to load config.json in the current working directory. If it isn't there, the server won't start. If you want to specify a different config file, do so with ./kbserver -config=/path/to/config.json.

config.json

• KeyboardName - A string that uniquely distinguishes the keyboard to be manipulated from all other lines of output from info usb on the qemu monitor.

• VendorID - A 4-digit hex identifier corresponding to your hardware vendor. Find this in the output of lsusb.

• ProductID - A 4-digit hex identifier representing your specific product model. Find this in the output of lsusb.

• ManagementPort - The TCP on which to listen for connections from kbclient. Always binds to localhost.

Sample:

{
    "KeyboardName":"Corsair K65 Gaming Keyboard",
    "VendorID":"1b1c",
    "ProductID":"1b07"
}

TODO

• Auto-generate config file
• (?) Develop Windows wrapper to listen for key events?
• Comment EVERYTHING
• Develop tests