FreeBSD 8, i386 PV panic at idle

[Sean Bruno]

Simple left my xen domu running over night.  The console looks like
this:
rtc0: [XEN] xen_rtc_settime
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
[XEN] hypervisor wallclock nudged; nudging TOD.
panic: HYPERVISOR_update_va_mapping(((unsigned long)(sysmaps->CADDR2)),
(0x001 | 0x002 | xpmap_ptom(((m)->phys_addr)) | 0x020 | 0x040),
UVMF_INVLPG| UVMF_ALL) <
0: /dumpster/scratch/sbruno-scratch/8/sys/i386/xen/pmap.c:3400
cpuid = 0
KDB: enter: panic
[thread pid 61868 tid 100085 ]
Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
db> bt
Tracing pid 61868 tid 100085 td 0xc3e0d2e0
kdb_enter(c0369837,c0369837,c03915fd,e1ae0acc,0,...) at kdb_enter+0x3a
panic(c03915fd,c0398e3e,c039848a,d48,c05bc140,...) at panic+0x134
pmap_zero_page(c15d9038,e,0,40,e1ae0c14,...) at pmap_zero_page+0x112
vm_fault(c350e0ec,bf7ee000,2,8,bf7eed78,...) at vm_fault+0x1201
dblfault_handler() at dblfault_handler+0x4d7
--- trap 0x17, eip = 0, esp = 0, ebp = 0 ---


The Dom0 has the following on its console:
entOS release 5.6 (Final)
Kernel 2.6.18-238.12.1.el5xen on an x86_64

xen1.freebsd.org login: (XEN) mm.c:2315:d146 Bad type (saw
4800000000000002 != exp e000000000000000) for mfn 1269f1 (pfn 25d7a)
(XEN) mm.c:807:d146 Error getting mfn 1269f1 (pfn 25d7a) from L1 entry
00000001269f1063 for l1e_owner=146, pg_owner=146



DomU config:
#============================================================================
# Python configuration setup for 'xm create'.
# This script sets the parameters used when a domain is created using
'xm create'.
# You use a separate script for each domain you want to create, or 
# you can set the parameters for the domain on the xm command line.
#============================================================================

#----------------------------------------------------------------------------
# Kernel image file.
#kernel = "/usr/lib/xen/boot/hvmloader"
kernel = "/var/virt/freebsd-8-stable-i386-domu-kernel"

#----------------------------------------------------------------------------
# device model to use: only qemu-dm available for now
#device_model = '/usr/lib64/xen/bin/qemu-dm'

#builder='hvm'

# Initial memory allocation (in megabytes) for the new domain.
memory = 855

# number of CPUS
vcpus = 1

# A name for your domain. All domains must have different names.
name = "ref8-xen32"
arch = "i386"

#Network interface. By default emules a realtek 8139. For a NetBSD guest
you
# have to disable re(4) and let rtk attach to use it.
# ne2k_pci emulates a pci ne2000 clone; this his cpu-hungry in dom0
# pcnet emulates a AMD PCnet-PCI controller; but it corrupts packets
with
# pcn(4) under NetBSD.
#vif = [ 'mac=00:16:3e:00:00:01, bridge=xenbr0, type=ioemu' ]
vif = [ 'mac=00:16:3e:00:00:01, bridge=xenbr0, type=vbd' ]

# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.
# For hvm domains you can only use hda to hdd. You can set extra types
# (e.g. cdrom)

disk = [
        'file:/var/virt/FreeBSD-8.2-RELEASE-i386-disc1.iso,hdc:cdrom,r',
        'file:/var/virt/ref8-xen32.bin,hda,w'
        ]

extra = "vfs.root.mountfrom=ufs:/dev/ad0s1a"
# floppy images; this doesn't seem to work currently. Use a iso image
instead.
#fda = '/home/domains/boot1.fs'

# boot device: a = floppy, c= hard drive, d= cdrom (with the disk entry
# before)
#
# boot CDROM image
#boot='d' 
# boot from DISK file
boot='c'

# By default, 'xm create' will try to open an X window on the current
display
# for the virtal framebuffer. You can have the virtal framebuffer in vnc
# instead, and connect using a vnc client (using localhost:$vncdisplay)
# If vncunused is set to 1 (this is the default value), vncdisplay
# will be set to the first unused port; so it's recommended to
#vfb = [ "type = vnc, vncdisplay = 1, vncunused = 0, display = TEST"  ]

#Xen emulates a PS/2 mouse, but the pointer in the guest has
difficulties
# tracking the absolute position. Xen can emulate a USB tablet in
addition
# to the mouse which will report the absolute position of the pointer,
# and make the mouse much easier to use. 
# 
usb=1
usbdevice='tablet'
#usbdevice='mouse'

serial='pty'
on_reboot='restart'
#============================================================================