In case you don?t need to debug the boot process you could wait for the Windows to start and only then start Windbg configure the communication options and hit break (ctrl+break) to initiate debug session. Symbols could be downloaded from: http://www.microsoft.com/whdc/devtools/debugging/symbolpkg.mspx Best regards, Yan. From: Vadim Rozenfeld [mailto:vrozenfe@xxxxxxxxxx] Sent: Tuesday, August 18, 2009 2:02 PM To: Tom Parkin Cc: Yan Vugenfirer; kvm@xxxxxxxxxxxxxxx Subject: Re: Using KVM for Windows kernel debugging On 08/18/2009 01:52 PM, Tom Parkin wrote: 2009/8/17 Tom Parkin <tom.parkin@xxxxxxxxx>: Thanks so much for that, Yan, it looks exactly like what I need. I'll give it a try when I'm back in the office. Having given it a try, I'm having some troubles which I hope someone may be able to assist with ? Here's my configuration : I have two Windows XP hosts running in two virtual machines[0]. One is set up as the "debugee" to export debugging information via. COM1, the other is set up as the "debugger" with the WinDBG kernel debugger installed. I have followed the instructions on the Wiki[1] for creating a virtual serial connection between the two VMs, and I am able to send messages between the two VMs using Hyperterm. However, I am unable to successfully establish a connection between the WinDBG debugger process and the debugee machine. The best I've managed so far is as follows : o Boot the debugger VM and start WinDBG o Boot the debugee VM o The debugee boots to the Windows bootloader screen. Immediately after that it appears to hang with a black screen, and it starts chewing CPU o Wait for a short time (~1-2min), after which the WinDBG process crashes on the debugger VM o Restart WinDBG and wait again for a short time (~1-2min). Again, WinDBG crashes o Restart WinDBG a third time. This time the debugger window shows "Kernel debugger connection established", although the window status bar still shows "Debugee not connected" Try to download symbols first. o Wait for some time (~5min), during which some further messages come up in the debugger. Eventually it seems to settle into a loop of "GetContextState failed" with the occasional "Unable to read KTHREAD address". Host (WinDbg) and target are running out-of-sync. And that appears to be that. I've left it to run for up to ~15 min, during which time the debugee VM window never comes out of the apparent black screen hang, and the debugee kvm process continues to chew CPU, pretty much pegging one of my cores at 100%. My questions: + The Wiki mentions a patch to the kvm-qemu sources[2]. Looking at the git tree it seems this change may be merged, so possibly this patch isn't required any more. Can anyone confirm this ? + Does anyone have a working Windows guest debugging setup working ? Could you share the details ? Of course, any suggestions on how to debug the entire configuration would be gratefully received ! Thanks, Tom [0]. I'm running ubuntu 9.04 with the distro-provided kvm package version "1:84+dfsg-0ubuntu12.3". I'm at somewhat of a loss to relate this to actual kvm-qemu releases... My kernel version is 2.6.28-14-generic. My cpu is a AMD Turion(tm)X2 Ultra DualCore Mobile ZM-86, and I'm running kvm_amd with the option "npt=0" to avoid kernel oopses when starting VM images. [1]. As provided by Yan previously; http://kvm.qumranet.com/kvmwiki/WindowsGuestDebug [2]. The link in the Wiki is for a private IP (10.0.0.1) but I think the patch is probably the same as the one referenced here: http://www.damogran.de/blog/archives/14-WinDbg-and-QEMU.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
