Cannot consistently break into network kernel debugger

I am doing hypervisor debugging and am unable to get Windbg consistently working.
* I tried serial debugging as MSDN recommends, but was never able to get WinDbg to connect
* I tried network debugging and was able to get it to work, but it is not consistent.
* I tried using vmdemux as per MSDN, but was unable to get it working properly
* I am currently using VirtualKd to debug my guest VM and network debugging to debug the hypervisor. This works about half the time. The other half of the time, I get a network Windbg connection with the hypervisor, but then am unable to break into the hypervisor once I’ve used VirtualKd a little( less than 5 commands after 30 seconds)

Sometimes, the network debugger responds, but only after a 1 minute delay. Other times, WinDbg will not be able to break in even after 10 minutes. This is with Windbg 10.0

Anyone have a good solution to this?

Using the information at (which I guess is where you have looked)
https://msdn.microsoft.com/en-us/library/windows/hardware/ff540647(v=vs.85).aspx
I have been successful in using 1394 to debug both the root partition
and hyper-v. That said, I have never ran WinDbg within the system I am
debugging to then further debug a VM running within hyper-v. Sounds like
you could be breaking something in that chain causing the problems you
are seeing.

Without breaking into the WinDbg instance you are using to debug the
guest VM, are you able to maintain a stable connection to the hyper-v
debug session? If not, maybe switch over to 1394 and see if you can
maintain a stable connection using it.

Pete


Kernel Drivers
Windows File System and Device Driver Consulting
www.KernelDrivers.com
866.263.9295

------ Original Message ------
From: xxxxx@yahoo.com
To: “Windows System Software Devs Interest List”
Sent: 12/7/2016 1:31:28 PM
Subject: [ntdev] Cannot consistently break into network kernel debugger

>I am doing hypervisor debugging and am unable to get Windbg
>consistently working.
>* I tried serial debugging as MSDN recommends, but was never able to
>get WinDbg to connect
>* I tried network debugging and was able to get it to work, but it is
>not consistent.
>* I tried using vmdemux as per MSDN, but was unable to get it working
>properly
>* I am currently using VirtualKd to debug my guest VM and network
>debugging to debug the hypervisor. This works about half the time.
>The other half of the time, I get a network Windbg connection with the
>hypervisor, but then am unable to break into the hypervisor once I’ve
>used VirtualKd a little( less than 5 commands after 30 seconds)
>
>Sometimes, the network debugger responds, but only after a 1 minute
>delay. Other times, WinDbg will not be able to break in even after 10
>minutes. This is with Windbg 10.0
>
>Anyone have a good solution to this?
>
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