Need help with windows debug tools - HPET problems on win2k864

Need help with windows debug tools - HPET problems on win2k864

[Beth Kon]

I ran into trouble trying to get the hpet working with win2k864. It
hangs very early on (black screen with "Windows is loading Files" at the
bottom). My guess is there are problems with our acpi/bios changes,
since they introduce some ACPI 2.0 structures and QEMU/KVM supports ACPI
1.0. We may not have enough 2.0 infrastructure to get it working right
for 64 bit. Win2k832 does work with the hpet, but 64 doesn't.

So! I need to figure out how to debug Windows and Anthony suggested that
there may be some people with experience here. 

I have set up a host and a target guest on kvm, one started with -serial
pty and the other with -serial /dev/pts/0 (which was the value spit out
by the first guest). I'm trying to test the serial connection by
following instructions at:

http://msdn.microsoft.com/en-us/library/cc266323.aspx

which just sends a message over the serial connection from one guest to
the other. I specify the baud rate as shown , assuming it shouldn't
matter in this emulated environment, but I can't get the message to show
up. Does anyone have any suggestions? Is this the proper way to set up a
"null modem cable" between 2 guests?

Also, reading the windows docs, I see that there are several debuggers,
like kd, cdb, ntsd, and windbg (gui wrapper). I downloaded the debugging
package from:

http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx#a

which claims to download all tools, but I can't figure out how to invoke
kd directly. It appears not to be there. I can invoke WinDbg from the
Start menu, however, and I assume that will be sufficient for my needs.

Lastly, I still haven't figured out if these debuggers require setup on
both host and target. If so, they will be useless for my needs since I
get a hang before the OS boots. But there must be some way to debug boot
issues. 

If anyone has any comments/suggestions on any of the above, I'd be very
appreciative!

-- 
Elizabeth Kon (Beth)
IBM Linux Technology Center
Open Hypervisor Team
email: eak@us.ibm.com

Re: Need help with windows debug tools - HPET problems on win2k864

[Sebastian Herbszt]

Beth Kon wrote:

>I ran into trouble trying to get the hpet working with win2k864. It
> hangs very early on (black screen with "Windows is loading Files" at the
> bottom). My guess is there are problems with our acpi/bios changes,
> since they introduce some ACPI 2.0 structures and QEMU/KVM supports ACPI
> 1.0. We may not have enough 2.0 infrastructure to get it working right
> for 64 bit. Win2k832 does work with the hpet, but 64 doesn't.

Does win2k864 without hpet work?
 
> So! I need to figure out how to debug Windows and Anthony suggested that
> there may be some people with experience here. 
> 
> I have set up a host and a target guest on kvm, one started with -serial
> pty and the other with -serial /dev/pts/0 (which was the value spit out
> by the first guest). I'm trying to test the serial connection by
> following instructions at:
> 
> http://msdn.microsoft.com/en-us/library/cc266323.aspx
> 
> which just sends a message over the serial connection from one guest to
> the other. I specify the baud rate as shown , assuming it shouldn't
> matter in this emulated environment, but I can't get the message to show
> up. Does anyone have any suggestions? Is this the proper way to set up a
> "null modem cable" between 2 guests?
> 
> Also, reading the windows docs, I see that there are several debuggers,
> like kd, cdb, ntsd, and windbg (gui wrapper). I downloaded the debugging
> package from:
> 
> http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx#a
> 
> which claims to download all tools, but I can't figure out how to invoke
> kd directly. It appears not to be there. I can invoke WinDbg from the
> Start menu, however, and I assume that will be sufficient for my needs.
> 
> Lastly, I still haven't figured out if these debuggers require setup on
> both host and target. If so, they will be useless for my needs since I
> get a hang before the OS boots. But there must be some way to debug boot
> issues. 
> 
> If anyone has any comments/suggestions on any of the above, I'd be very
> appreciative!

Maybe the article "Using the windows debugger under Xen" at
http://wiki.xensource.com/xenwiki/XenWindowsGplPv can help.

- Sebastian

Re: Need help with windows debug tools - HPET problems on win2k864

[Avi Kivity]

Beth Kon wrote:
> I ran into trouble trying to get the hpet working with win2k864. It
> hangs very early on (black screen with "Windows is loading Files" at the
> bottom). My guess is there are problems with our acpi/bios changes,
> since they introduce some ACPI 2.0 structures and QEMU/KVM supports ACPI
> 1.0. We may not have enough 2.0 infrastructure to get it working right
> for 64 bit. Win2k832 does work with the hpet, but 64 doesn't.
>
> So! I need to figure out how to debug Windows and Anthony suggested that
> there may be some people with experience here. 
>   

Something that's worked for me is to enable memory dump triggered by
ctrl-ctrl-scroll-lock.  There's some registry key you set, and on the
next hang you can generate a memory dump, which you can then analyze
with windbg.

Of course, your hang might well occur earlier than disk driver
initialization, so this is not bulletproof.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Re: Need help with windows debug tools - HPET problems on win2k864

[Beth Kon]

On Sat, 2008-09-13 at 07:50 +0300, Avi Kivity wrote:
> Beth Kon wrote:
> > I ran into trouble trying to get the hpet working with win2k864. It
> > hangs very early on (black screen with "Windows is loading Files" at the
> > bottom). My guess is there are problems with our acpi/bios changes,
> > since they introduce some ACPI 2.0 structures and QEMU/KVM supports ACPI
> > 1.0. We may not have enough 2.0 infrastructure to get it working right
> > for 64 bit. Win2k832 does work with the hpet, but 64 doesn't.
> >
> > So! I need to figure out how to debug Windows and Anthony suggested that
> > there may be some people with experience here. 
> >   
> 
> Something that's worked for me is to enable memory dump triggered by
> ctrl-ctrl-scroll-lock.  There's some registry key you set, and on the
> next hang you can generate a memory dump, which you can then analyze
> with windbg.
> 
> Of course, your hang might well occur earlier than disk driver
> initialization, so this is not bulletproof.
> 
The problem is, I've been told (and confirmed with a test) I can't add
the hpet after windows is installed. It needs to be present for
installation, and I'm getting the black screen at the start of the
install. So there is no registry to play with yet. My guess is this is
just too early to get useful debug, though I was hoping a checked build
would provide information over the serial port even during install. I'll
keep trying to see if there's a way to make that happen.

Did you need a host and target for the kind of memory dump analysis you
did? Or just use windbg on a local dump file? I ask because I'm trying
to figure out if the "-serial pty" and "-serial /dev/pts/0" is the right
way to set up the null modem cable between 2 guests.
-- 
Elizabeth Kon (Beth)
IBM Linux Technology Center
Open Hypervisor Team
email: eak@us.ibm.com