amd64 domU kernels hanging

[Jeff Rizzo <riz%tastylime.net@localhost>]

Both an INSTALL and regular domU kernel seem to be hanging during boot 
in -current (amd64, haven't tested i386pae) at the moment.  I observe 
this both on my NetBSD dom0 system, and rackspace's linux dom0.  I 
haven't had a chance to see how far back this goes yet;  I'll look into 
it tomorrow unless someone else knows what's up:



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NetBSD 5.99.52 (INSTALL_XEN3_DOMU) #0: Fri May 27 06:36:44 UTC 2011
    
builds%b8.netbsd.org@localhost:/home/builds/ab/HEAD/amd64/201105270510Z-obj/home/builds/ab/HEAD/src/sys/arch/amd64/compile/INSTALL_XEN3_DOMU
total memory = 512 MB
avail memory = 481 MB
mainbus0 (root)
hypervisor0 at mainbus0: Xen version 3.3
vcpu0 at hypervisor0: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz, id 0x206a7
xenbus0 at hypervisor0: Xen Virtual Bus Interface
xencons0 at hypervisor0: Xen Virtual Console Driver
xencons0: using event channel 2
xbd0 at xenbus0 id 1: Xen Virtual Block Device Interface
xbd1 at xenbus0 id 2: Xen Virtual Block Device Interface
xbd2 at xenbus0 id 3: Xen Virtual Block Device Interface
xennet0 at xenbus0 id 0: Xen Virtual Network Interface
xennet0: MAC address 02:02:02:11:11:11
balloon0 at xenbus0 id 0: Xen Balloon driver
balloon0: current reservation: 524288 KiB