Kernel debugging with windbg & VirtualBox via serial port

I’m been trying to get kernel debugging working with VirtualBox. Both my host and the VM guest are running Windows 7.

Here’s how I was finally able to get it working.

On the VM guest

Created new boot entry with:

1. bcdedit /copy {current} /d “Windows with with serial debugging”, copy the created {guid}
2. bcdedit /set {guid} debug on
3. bcdedit /set {guid} debugport 4, for some reason none of the others ports worked for me
4. bcdedit /set {guid} baudrate 115200

Shutdown the VM, then enabled a serial port in VirtualBox:

On the host

Launched windbg and connected using the following settings:

Back on the VM guest

Start the VM guest, and select the new boot option:

And finally it worked 🙂