# FreeBSD 9.0-RELEASE on XEN



## romihs (Sep 2, 2012)

Hello,

I have FreeBSD 9.0 GENERIC running in a HVM Xen domU, and it seams to run fine.

I am having problems booting the XENHVM kernel though. I built the XENHVM kernel so that the kernel would include the PV drivers to improve performance (read and write speeds on the iscsi volumes is VERY poor).

My system is Xen 4.2-unstable -24785 with Debian Squeeze for my dom0.


The XENHVM kernel hangs during boot up:


```
.
.
.
qpi0: <QPI system bus> on motherboard
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x100>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
Timecounters tick every 10.000 msec
xenbusb_front0: <Xen Frontend Devices> on xenstore0


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0xfffffe010277442f
fault code		= supervisor write data, page not present
instruction pointer	= 0x20:0xffffffff80aa3ba8
stack pointer	        = 0x28:0xffffffff813fb9f0
frame pointer	        = 0x28:0xffffffff813fba30
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 0 (swapper)
trap number		= 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
#0 0xffffffff808691ae at kdb_backtrace+0x5e
#1 0xffffffff80833ff7 at panic+0x187
#2 0xffffffff80b2d690 at trap_fatal+0x290
#3 0xffffffff80b2d9d9 at trap_pfault+0x1f9
#4 0xffffffff80b2de9f at trap+0x3df
#5 0xffffffff80b1839f at calltrap+0x8
#6 0xffffffff80aa5a4a at xs_directory+0x7a
#7 0xffffffff80aa5ca5 at xs_exists+0x15
#8 0xffffffff80aa1e4c at xenbusb_add_device+0x9c
#9 0xffffffff80aa30cb at xenbusb_front_enumerate_type+0x5b
#10 0xffffffff80aa2e8e at xenbusb_attach+0xfe
#11 0xffffffff808625c9 at device_attach+0x69
#12 0xffffffff8086401a at bus_generic_attach+0x1a
#13 0xffffffff80aa3b71 at xs_attach_deferred+0x21
#14 0xffffffff8085df2b at run_interrupt_driven_config_hooks+0xab
#15 0xffffffff8085e29c at boot_run_interrupt_driven_config_hooks+0x2c
#16 0xffffffff807e8c97 at mi_startup+0x77
#17 0xffffffff802a0cac at btext+0x2c
Uptime: 1s
Automatic reboot in 15 seconds - press a key on the console to abort
```

The configuration file of the VM is:


```
builder = "hvm"
kernel = "/usr/lib/xen/boot/hvmloader"
vcpus = 4
memory = 2048
device_model = '/usr/lib/xen/bin/qwmu-dm'
disk =	[
	'file:/home/sandi/Downloads/freebsd.iso,hdc:cdrom,r',
	'phy:/dev/xen-dom0/freebsd,hda,w'
	]
name = "freebsd"
vif = ['bridge=xenbr0,mac=00:00:3E:00:AF:D8']
serial = 'pty'

pci = [ '05:00.0' ]

 vnc=1
 vnclisten="0.0.0.0"
 vncconsole=1
 vncpasswd=''
```

I use the same cfg file to start the GENERIC or XENHVM version of the kernel.


Any ideas of what is causing this and how to get it sorted out?
I would really like to improve the throughput of the iscsi volumes (on zfs pool).


Thanks

Sandi


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## donduq (Nov 8, 2012)

Look at the typo:


```
device_model = '/usr/lib/xen/bin/q[B]w[/B]mu-dm'
```

Would that be the problem?


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