Using WinDbg to debug Hyper-V

WINDBG
1

Hello All!

I’m trying to debug Hyper-V communication and come across of the strange problem.
My Setup: Windows 10 w/o HYPER-V installed + VMWare Workstation 16 Pro + WinDbg.

In VMWARE I have a VM running Windows 10 2004 with HYPER-V enabled. VM uses Serial Port connected to the named pipe. WinDbg connects to the named pipe as well. The same setup work fine for the Kernel debugger (using, of course, another named pipe)

When I’m breaking into WinDbg at startup (e.g. using “-d” switch for WinDbg), I can do everything: set break points, stop on break points, dump memory, debug initialization of Hyper-V, etc). However, after VM is completely started, I can break into WinDbg only once. After resuming the VM execution (F5 or ‘g’) VM is completely frozen. I also cannot break into debugger for the second time.

Is anybody encountered similar problem? Any suggestion?

Thank you in advance,

Al

2

I think you need two instances of Windbg to debug HyperV. This should be a good resource for debugging HyperV: https://msrc-blog.microsoft.com/2018/12/10/first-steps-in-hyper-v-research/

3

I tried initially with two instances of WinDbg. As I wrote in my initial post - The The same setup work fine for debug Virtual Partition (Windows Kernel) using, of course, another named pipe).

Unfortunately regardless second instance of WinDbg is connected or not - the problem remain: I can debug Hyper-V initialization, but as soon as Virtual Partition is up and running, any break to WinDbg instance connected to Hyper-V itself will be the last one.

Is anybody encountered similar problem? Any suggestion?

4

I have the same problem …