Page 1 of 1

Windbg to Win Server 2008 guest - possible?

Posted: 6. Nov 2008, 21:14
by tbroberg
I desperately need to debug a problem on a Windows Server 2008 VM at a kernel level.

I've tried setting up serial ports through named pipe, physical, and disconnected. W2k8 doesn't see the ports.

Tried COM1 - COM5.

I add them as legacy devices and W2k8 adds the devices but with problems - conflicts with the address range of the PCI bus and with the IRQ of ACPI. Apparently the serial drivers are being added in an address range that belongs to PCI, but are hooked in outside the scope of the PCI driver.

All tricks listed on the forum for dealing with serial ports don't seem to work for me with W2k8.

Has anybody gotten windbg to work with a named pipe? When you setup serial to a named pipe under VBox, is that named pipe accessible on the client system like it appears to be in VMWare? I'm guessing not.

Any other ideas, or am I doomed to switch to VMWare or even a physical server?

TIA,
- Tim.

Posted: 27. Nov 2008, 03:01
by geetasg
I am running into the same problem. I am able to see the COM port if I use "User-defined" for port number and then use an I/O port value that does not conflict with PCI. But I can not get the pipe to work. I am not able to do attach windbg to the guest kernel (which is my primary goal).

Did you find any solution?

Thanks in advance.

Posted: 27. Nov 2008, 03:36
by tbroberg
'fraid not.

XP worked flawlessly immediately. W2k8 wouldn't work no matter what I tried.

In my case, I reverted to a physical system before discovering that the activity I was trying to track down was in user mode after all.

User mode windbg worked great, I solved the problem, and collected many high-fives, but still have no idea how to get W2k8 kernel mode debug to work in a VM.

Posted: 12. Feb 2009, 01:04
by agiantalienforce
Same problem here. Anybody has a hint? VM just freezes when loading the software i'm testing and it would be great to figure out what's happening. BTW, i'm using W2K8 x64 on x32 machine.

VM freezes? That's progress!

Posted: 12. Feb 2009, 01:45
by tbroberg
"VM just freezes when loading the software i'm testing"

If you're getting to the point of loading the software you're way ahead of us. We couldn't even see the serial port under Win2k8.

Can you see the COM port?

Perhaps they improved the drivers since 1.6.x...

Re: VM freezes? That's progress!

Posted: 12. Feb 2009, 17:36
by agiantalienforce
tbroberg wrote:"VM just freezes when loading the software i'm testing"

If you're getting to the point of loading the software you're way ahead of us. We couldn't even see the serial port under Win2k8.

Can you see the COM port?

Perhaps they improved the drivers since 1.6.x...
Tim, i can't see the port inside W2K8 guest. It is conflicting with PCI Bus (afair). Also, i think that even if that would work (seeing the port), i would still fail to attach a debugger from the host, since Vbox seems to lock the port (if i start windbg attached to port, VM cannot start and vice versa).

EDIT: forgot to add that both VMware and Parallels Server have option to specify how COM port will behave. I.e. VM is COM server or client.

WinDBG + VirtualBox = :-(

Posted: 24. Feb 2009, 16:26
by nixxcode
I've had no luck getting in getting WinDBG to connect to my guest OS (XP) over a virtual serial port. I can debug to my heart's content with a VMware workstation host.

Is seems all of this could be related to the following ticket:
http://www.virtualbox.org/ticket/1947

That ticket mentions a problem due to the polling nature of serial port access; VMware has some special optimisations for that, could they be the reason VMware works nicely?
http://www.vmware.com/support/ws5/doc/w ... anced.html