> ftp://ftp.netbsd.org/pub/NetBSD-daily/netbsd-3/200604080000Z/i386/binary/=
kernel/netbsd-XEN3_U.gz

Using this kernel I do also get a panic:

    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

panic: HYPERVISOR_mmu_update failed

Stopped in pid 0.1 () at        netbsd:cpu_Debugger+0x4:        popl    %eb=
p
cpu_Debugger(c03fb224,c04fee34,1,0,0) at netbsd:cpu_Debugger+0x4
panic(c03fbde4,2,7,0,43bbd74) at netbsd:panic+0x135
xpq_flush_queue(43bbd74,a8c0a63,c04feed8,c0368415,c044cc40) at netbsd:xpq_f=
lush_
queue+0x5c
pmap_enter(c047a960,c075d000,80fb000,7,13) at netbsd:pmap_enter+0x71e
uvm_km_alloc1(c044cc40,1000,0,c0474380,c0474380) at netbsd:uvm_km_alloc1+0x=
153
pmap_init(c075c000,fbc00000,c04790a0,c075c000,fbc00000) at netbsd:pmap_init=
+0x23

uvm_init(c03f3dcf,c03eae80,9,0,0) at netbsd:uvm_init+0x5f
main(0,0,0,0,0) at netbsd:main+0x61
ds          0x11
es          0x11
fs          0x31
gs          0x11
edi         0xc03fbde4  copyright+0x10f64
esi         0x100
ebp         0xc04fedf8  emul_freebsd_object+0x82d18
ebx         0xc04fee34  emul_freebsd_object+0x82d54
edx         0xc0504000  emul_freebsd_object+0x87f20
ecx         0
eax         0x1
eip         0xc03795b4  cpu_Debugger+0x4
--db_more--