custom kernel freezes when using KVM

	1) About two weeks ago I installed 8.0beta3/amd64 on new
hardware.  Except for one problem, now solved, everything went
smoothly and I was a happy camper.
	2) Several days later I hooked it up to a (USB-) KVM; I also
connected a Windows XP box and was able to switch back and forth
between them with no problems.
	3) Three days ago, I updated the system source and did the
per-handbook system upgrade using the appended kernel config file.
	4) Since then, using the KVM - whether or not the Windows
machine is running - causes the FreeBSD box to freeze hard (requires
hardware reset).
	While I have updated installed ports (list available on
request), it seems reasonable to believe this is a OS failure and
the new kernel is responsible.
	Is there anything I left out, or put in, that would cause this
breakage?  Has snyone seen this kind of thing before?

	Respectfully,


				Robert Huff


#
# JERUSALEM --  kernel configuration file for FreeBSD/amd64
#
# For more information on this file, please read the config(5) manual page,
# and/or the handbook section on Kernel Configuration Files:
#
#    http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files.
# If you are in doubt as to the purpose or necessity of a line, check first
# in NOTES.
#
# $FreeBSD: src/sys/amd64/conf/GENERIC,v 1.531.2.2 2009/08/13 17:54:11 attilio Exp $

cpu			HAMMER
ident		JERUSALEM

# To statically compile in device wiring instead of /boot/device.hints
#hints		"GENERIC.hints"		# Default places to look for devices.

# Use the following to compile in values accessible to the kernel
# through getenv() (or kenv(1) in userland). The format of the file
# is 'variable=value', see kenv(1)
#
# env		"GENERIC.env"

makeoptions	DEBUG=-g		# Build kernel with gdb(1) debug symbols

options 	SCHED_ULE		# ULE scheduler
options 	PREEMPTION		# Enable kernel thread preemption
options 	INET			# InterNETworking
options 	INET6			# IPv6 communications protocols
options 	SCTP			# Stream Control Transmission Protocol
options 	FFS			# Berkeley Fast Filesystem
options 	SOFTUPDATES		# Enable FFS soft updates support
options 	UFS_ACL			# Support for access control lists
options 	UFS_DIRHASH		# Improve performance on big directories
options 	UFS_GJOURNAL		# Enable gjournal-based UFS journaling
options 	MD_ROOT			# MD is a potential root device
options 	NFSCLIENT		# Network Filesystem Client
options 	NFSSERVER		# Network Filesystem Server
options 	NFSLOCKD		# Network Lock Manager
options 	NFS_ROOT		# NFS usable as /, requires NFSCLIENT
options 	MSDOSFS			# MSDOS Filesystem
options 	CD9660			# ISO 9660 Filesystem
options 	PROCFS			# Process filesystem (requires PSEUDOFS)
options 	PSEUDOFS		# Pseudo-filesystem framework
options 	GEOM_PART_GPT		# GUID Partition Tables.
options 	GEOM_LABEL		# Provides labelization
options 	GEOM_PART_BSD
options 	GEOM_PART_EBR
options 	GEOM_PART_EBR_COMPAT
options 	GEOM_PART_MBR
options 	COMPAT_43TTY		# BSD 4.3 TTY compat (sgtty)
options 	COMPAT_IA32		# Compatible with i386 binaries
options 	COMPAT_FREEBSD4		# Compatible with FreeBSD4
options 	COMPAT_FREEBSD5		# Compatible with FreeBSD5
options 	COMPAT_FREEBSD6		# Compatible with FreeBSD6
options 	COMPAT_FREEBSD7		# Compatible with FreeBSD7
options 	SCSI_DELAY=1000		# Delay (in ms) before probing SCSI
options 	STACK			# stack(9) support
options 	SYSVSHM			# SYSV-style shared memory
options 	SYSVMSG			# SYSV-style message queues
options 	SYSVSEM			# SYSV-style semaphores
options 	P1003_1B_SEMAPHORES	# POSIX-style semaphores
options 	_KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options 	PRINTF_BUFR_SIZE=128	# Prevent printf output being interspersed.
options 	KBD_INSTALL_CDEV	# install a CDEV entry in /dev
options 	HWPMC_HOOKS		# Necessary kernel hooks for hwpmc(4)
options 	AUDIT			# Security event auditing
options 	MAC			# TrustedBSD MAC Framework
options	FLOWTABLE		# per-cpu routing cache

#

options   IPFIREWALL              #firewall
options   IPFIREWALL_VERBOSE      #enable logging to syslogd(8)
options   IPFIREWALL_VERBOSE_LIMIT=100    #limit verbosity
options   IPFIREWALL_DEFAULT_TO_ACCEPT    #allow everything by default
options   IPFIREWALL_NAT          #ipfw kernel nat support
options	LIBALIAS				# required for NAT

# Debugging for use in -current
options 	KDB			# Enable kernel debugger support.
options 	DDB			# Support DDB.
options 	GDB			# Support remote GDB.
options 	INVARIANTS		# Enable calls of extra sanity checking
options 	INVARIANT_SUPPORT	# Extra sanity checks of internal structures, required by INVARIANTS
options 	WITNESS			# Enable checks to detect deadlocks and cycles
options 	WITNESS_SKIPSPIN	# Don't run witness on spinlocks for speed

# Make an SMP-capable kernel by default
options 	SMP			# Symmetric MultiProcessor Kernel

# CPU frequency control
device		cpufreq

# Bus support.
device		acpi
device		pci

device		drm		# DRM core module required by DRM drivers
device		radeondrm	# ATI Radeon

# Floppy drives

# ATA and ATAPI devices
device		ata
device		atadisk		# ATA disk drives
device		ataraid		# ATA RAID drives
device		atapicd		# ATAPI CDROM drives
device		atapifd		# ATAPI floppy drives
device		atapist		# ATAPI tape drives
options 	ATA_STATIC_ID	# Static device numbering

# SCSI Controllers
					# output.  Adds ~128k to driver.
					# output.  Adds ~215k to driver.


# SCSI peripherals
device		scbus		# SCSI bus (required for SCSI)
device		ch		# SCSI media changers
device		da		# Direct Access (disks)
device		sa		# Sequential Access (tape etc)
device		cd		# CD
device		pass		# Passthrough device (direct SCSI access)
device		ses		# SCSI Environmental Services (and SAF-TE)

# RAID controllers interfaced to the SCSI subsystem
#XXX it is not 64-bit clean, -scottl

# RAID controllers
#XXX pointer/int warnings

# atkbdc0 controls both the keyboard and the PS/2 mouse

device		kbdmux		# keyboard multiplexer

device		vga		# VGA video card driver

device		splash		# Splash screen and screen saver support

# syscons is the default console driver, resembling an SCO console
device		sc

device		agp		# support several AGP chipsets

# PCCARD (PCMCIA) support
# PCMCIA and cardbus bridge support

# Serial (COM) ports
device		uart		# Generic UART driver

# Parallel port
device		ppc
device		ppbus		# Parallel port bus (required)
device		lpt		# Printer
device		plip		# TCP/IP over parallel
device		ppi		# Parallel port interface device

# If you've got a "dumb" serial or parallel PCI card that is
# supported by the puc(4) glue driver, uncomment the following
# line to enable it (connects to sio, uart and/or ppc drivers):

# PCI Ethernet NICs.

# PCI Ethernet NICs that use the common MII bus controller code.
# NOTE: Be sure to keep the 'device miibus' line in order to use these NICs!
device		miibus		# MII bus support

# ISA Ethernet NICs.  pccard NICs included.
# 'device ed' requires 'device miibus'

# Wireless NIC cards

# Pseudo devices.
device		loop		# Network loopback
device		random		# Entropy device
device		ether		# Ethernet support
device		tun		# Packet tunnel.
device		pty		# BSD-style compatibility pseudo ttys
device		md		# Memory "disks"
device		gif		# IPv6 and IPv4 tunneling
device		faith		# IPv6-to-IPv4 relaying (translation)
device		firmware	# firmware assist module

# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
# Note that 'bpf' is required for DHCP.
device		bpf		# Berkeley packet filter

# USB support
device		uhci		# UHCI PCI->USB interface
device		ohci		# OHCI PCI->USB interface
device		ehci		# EHCI PCI->USB interface (USB 2.0)
device		usb		# USB Bus (required)
device		uhid		# "Human Interface Devices"
device		ukbd		# Keyboard
device		ulpt		# Printer
device		umass		# Disks/Mass storage - Requires scbus and da
device		ums		# Mouse
# USB Serial devices
device		uark		# Technologies ARK3116 based serial adapters
device		ubsa		# Belkin F5U103 and compatible serial adapters
device		uftdi		# For FTDI usb serial adapters
device		uipaq		# Some WinCE based devices
device		uplcom		# Prolific PL-2303 serial adapters
device		uslcom		# SI Labs CP2101/CP2102 serial adapters
device		uvisor		# Visor and Palm devices
device		uvscom		# USB serial support for DDI pocket's PHS
# USB Ethernet, requires miibus

# FireWire support