Hi.

I just compiled new 4.0 kernel from the latest sources and this is what 
happens when I boot my DomU:

troll# xm create xxx.yyy.org ; xm console xxx.yyy.org
Using config file "/usr/local/etc/xen/xxx.yyy.org".
Started domain xxx.yyy.org
vcpu0: Intel (686-class), 3000.35 MHz, id 0xf43
vcpu0: features bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
vcpu0: features bfebfbff<PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX>
vcpu0: features bfebfbff<FXSR,SSE,SSE2,SS,HTT,TM,SBF>
vcpu0: I-cache 12K uOp cache 8-way
vcpu0: ITLB 4K/4M: 64 entries
vcpu0: DTLB 4K/4M: 64 entries
debug virtual interrupt using event channel 3
xenbus0 at hypervisor0: Xen Virtual Bus Interface
xencons0 at hypervisor0: Xen Virtual Console Driver
xencons0: console major 143, unit 0
xencons0: using event channel 2
npx0 at hypervisor0: using exception 16
pci0 at hypervisor0 bus 0: configuration mode -1
pci0: i/o space, memory space enabled
panic: pci_make_tag: mode not configured

Additional info:
xentools3-3.1.0     Userland Tools for Xen
xenkernel3-3.1.0    Xen3 Kernel
Dom0 runs on CURRENT: NetBSD 4.99.21 (XEN3_DOM0Y) #2: Thu Jun 28 10:13:37 CEST 
2007 

The CURRENT DomU from the same time as Dom0 runs just fine.

Cheers,
Marcin.