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

[Beth Kon <eak@us.ibm.com>]

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