Hi 
Michael,
After you change your BIOS's VT-d setting from Disabled to Enabled 
(or from Enabled to Disabled), can you try power cycle your host (unplug the 
power cord and wait for some time)? 
If this works, it would be a BIOS 
issue.
 
Thanks,
-- 
Dexuan
Xen 3.4.1-rc8 iommu crash on Optiplex 760 ( Core2 E8400, 
Q43 / ICH10D )
 
Using the following build procedure from a clean amd64 
debian lenny install
On an optiplex 760 with the latest bios (A03)
 
apt-get install ssh less bcc bin86 gawk bridge-utils 
iproute libcurl3 libcurl4-openssl-dev bzip2 module-init-tools transfig tgif 
texinfo pciutils-dev mercurial build-essential make gcc libc6-dev zlib1g-dev 
python python-dev python-twisted libncurses5-dev patch libvncserver-dev 
libsdl-dev libjpeg62-dev gcc-multilib git-core
hg clone 
http://xenbits.xensource.com/xen-3.4-testing.hg
cd xen-3.4-testing.hg
make world -j2 debug=y debugger=y
make install -j2 debug=y debugger=y
 
Xen boots without a problem if iommu is disabled but
if I enable iommu no matter the boot time parameters xen 
crashes as follows
 
__  
__            
_____ _  _    
_             
___
 \ \/ /___ _ __   
|___ /| || |  / |   _ __ ___( _ 
)
  \  // _ \ '_ 
\    |_ \| || |_ | |__| '__/ __/ _ \
  /  \  
__/ | | |  ___) |__   _|| |__| | 
| (_| (_) |
 /_/\_\___|_| |_| |____(_) 
|_|(_)_|  |_|  \___\___/
 
(XEN) Xen version 3.4.1-rc8 (***@***) (gcc version 4.3.2 
(Debian 4.3.2-1.1) ) Thu Jul 23 18:59:18 MDT 2009
(XEN) Latest ChangeSet: Thu Jul 23 09:08:13 2009 +0100 
19702:0171f9316e25
(XEN) Command line: console=com1 com1=57600,8n1 
iommu=passthrough iommu_inclusive_mapping=1
(XEN) Video information:
(XEN)  VGA is text mode 80x25, font 
8x16
(XEN)  VBE/DDC methods: V2; EDID 
transfer time: 1 seconds
(XEN) Disc information:
(XEN)  Found 1 MBR signatures
(XEN)  Found 1 EDD information 
structures
(XEN) Xen-e820 RAM map:
(XEN)  0000000000000000 - 
000000000009ec00 (usable)
(XEN)  00000000000f0000 - 
0000000000100000 (reserved)
(XEN)  0000000000100000 - 
00000000cfdffc00 (usable)
(XEN)  00000000cfdffc00 - 
00000000cfe53c00 (ACPI NVS)
(XEN)  00000000cfe53c00 - 
00000000cfe55c00 (ACPI data)
(XEN)  00000000cfe55c00 - 
00000000d0000000 (reserved)
(XEN)  00000000e0000000 - 
00000000f0000000 (reserved)
(XEN)  00000000fec00000 - 
00000000fed00400 (reserved)
(XEN)  00000000fed20000 - 
00000000feda0000 (reserved)
(XEN)  00000000fee00000 - 
00000000fef00000 (reserved)
(XEN)  00000000ffb00000 - 
0000000100000000 (reserved)
(XEN)  0000000100000000 - 
0000000128000000 (usable)
(XEN) System RAM: 3965MB (4060788kB)
(XEN) ACPI: RSDP 000FEC00, 0024 (r2 DELL  
)
(XEN) ACPI: XSDT 000FC7EF, 0074 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: FACP 000FC91F, 00F4 (r3 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: DSDT FFF1BE4D, 53BE (r1   
DELL    dt_ex     
1000 INTL 20050624)
(XEN) ACPI: FACS CFDFFC00, 0040
(XEN) ACPI: SSDT FFF2132A, 00AA (r1   
DELL    st_ex     
1000 INTL 20050624)
(XEN) ACPI: APIC 000FCA13, 0092 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: BOOT 000FCAA5, 0028 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: ASF! 000FCACD, 0096 (r32 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: MCFG 000FCB63, 003E (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: HPET 000FCBA1, 0038 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: TCPA 000FCDFD, 0032 (r1 
DELL    
B10K          
15 ASL  
      61)
(XEN) ACPI: DMAR 000FCE2F, 00D8 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) ACPI: SLIC 000FCBD9, 0176 (r1 
DELL    
B10K          
15 ASL        61)
(XEN) NUMA turned off
(XEN) Faking a node at 
0000000000000000-0000000128000000
(XEN) Domain heap initialised
(XEN) found SMP MP-table at 000fe710
(XEN) DMI 2.5 present.
(XEN) Using APIC driver default
(XEN) ACPI: PM-Timer IO Port: 0x808
(XEN) ACPI: ACPI SLEEP INFO: pm1x_cnt[804,0], 
pm1x_evt[800,0]
(XEN) 
ACPI:                  
wakeup_vec[cfdffc0c], vec_size[20]
(XEN) ACPI: Local APIC address 0xfee00000
(XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] 
enabled)
(XEN) Processor #0 7:7 APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x01] 
enabled)
(XEN) Processor #1 7:7 APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x05] 
disabled)
(XEN) ACPI: LAPIC (acpi_id[0x04] lapic_id[0x07] 
disabled)
(XEN) ACPI: LAPIC (acpi_id[0x05] lapic_id[0x00] 
disabled)
(XEN) ACPI: LAPIC (acpi_id[0x06] lapic_id[0x01] 
disabled)
(XEN) ACPI: LAPIC (acpi_id[0x07] lapic_id[0x02] 
disabled)
(XEN) ACPI: LAPIC (acpi_id[0x08] lapic_id[0x03] 
disabled)
(XEN) ACPI: LAPIC_NMI (acpi_id[0xff] high level 
lint[0x1])
(XEN) ACPI: IOAPIC (id[0x08] address[0xfec00000] 
gsi_base[0])
(XEN) IOAPIC[0]: apic_id 8, version 32, address 
0xfec00000, GSI 0-23
(XEN) ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl 
dfl)
(XEN) ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high 
level)
(XEN) ACPI: IRQ0 used by override.
(XEN) ACPI: IRQ2 used by override.
(XEN) ACPI: IRQ9 used by override.
(XEN) Enabling APIC mode:  
Flat.  Using 1 I/O APICs
(XEN) ACPI: HPET id: 0x8086a701 base: 0xfed00000
(XEN) [VT-D]dmar.c:485: Host address width 36
(XEN) [VT-D]dmar.c:494: found ACPI_DMAR_DRHD
(XEN) [VT-D]dmar.c:349: dmaru->address = fedc1000
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1b.0
(XEN) [VT-D]dmar.c:494: found ACPI_DMAR_DRHD
(XEN) [VT-D]dmar.c:349: dmaru->address = fedc3000
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:3.0
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:3.2
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:3.3
(XEN) [VT-D]dmar.c:494: found ACPI_DMAR_DRHD
(XEN) [VT-D]dmar.c:349: dmaru->address = fedc4000
(XEN) [VT-D]dmar.c:358: found INCLUDE_ALL
(XEN) [VT-D]dmar.c:498: found ACPI_DMAR_RMRR
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1d.0
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1d.1
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1d.2
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1d.7
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1a.0
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1a.1
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1a.2
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 0:1a.7
(XEN) Intel VT-d DMAR tables have been parsed.
(XEN) Using ACPI (MADT) for SMP configuration 
information
(XEN) Using scheduler: SMP Credit Scheduler (credit)
(XEN) Initializing CPU#0
(XEN) Detected 2992.547 MHz processor.
(XEN) CPU: L1 I cache: 32K, L1 D cache: 32K
(XEN) CPU: L2 cache: 6144K
(XEN) CPU: Physical Processor ID: 0
(XEN) CPU: Processor Core ID: 0
(XEN) VMX: Supported advanced features:
(XEN)  - APIC MMIO access 
virtualisation
(XEN)  - APIC TPR shadow
(XEN)  - Virtual NMI
(XEN)  - MSR direct-access bitmap
(XEN) HVM: VMX enabled
(XEN) Intel machine check reporting enabled on CPU#0.
(XEN) CPU0: Thermal monitoring enabled (TM2)
(XEN) CMCI: CPU0 has no CMCI support
(XEN) CPU0: Intel(R) Core(TM)2 Duo 
CPU     E8400  @ 3.00GHz 
stepping 0a
(XEN) Booting processor 1/1 eip 8c000
(XEN) Initializing CPU#1
(XEN) CPU: L1 I cache: 32K, L1 D cache: 32K
(XEN) CPU: L2 cache: 6144K
(XEN) CPU: Physical Processor ID: 0
(XEN) CPU: Processor Core ID: 1
(XEN) Intel machine check reporting enabled on CPU#1.
(XEN) CPU1: Thermal monitoring enabled (TM2)
(XEN) CMCI: CPU1 has no CMCI support
(XEN) CPU1: Intel(R) Core(TM)2 Duo 
CPU     E8400  @ 3.00GHz 
stepping 0a
(XEN) Total of 2 processors activated.
(XEN) ENABLING IO-APIC IRQs
(XEN)  -> Using new ACK method
(XEN) ..TIMER: vector=0xF0 apic1=0 pin1=2 apic2=-1 
pin2=-1
(XEN) checking TSC synchronization across 2 CPUs: 
passed.
(XEN) Platform timer is 14.318MHz HPET
(XEN) Brought up 2 CPUs
(XEN) microcode.c:73:d32767 microcode: CPU1 resumed
(XEN) Intel VT-d Snoop Control supported.
(XEN) Intel VT-d DMA Passthrough supported.
(XEN) Intel VT-d Queued Invalidation supported.
(XEN) Intel VT-d Interrupt Remapping supported.
(XEN) ----[ Xen-3.4.1-rc8  
x86_64  debug=y  Not tainted 
]----
(XEN) CPU:    0
(XEN) RIP:    
e008:[<ffff828c8012db81>] clear_fault_bits+0x2d/0xb3
(XEN) RFLAGS: 0000000000010202   
CONTEXT: hypervisor
(XEN) rax: ffff828bfff5aff8   rbx: 
0000000000004090   rcx: 0000000000000001
(XEN) rdx: 00000000ffffffff   rsi: 
0000000000000286   rdi: ffff830127fc80a0
(XEN) rbp: ffff828c80267db8   rsp: 
ffff828c80267db8   r8:  
ffff828bfff57000
(XEN) r9:  
ffff828bfff5700c   r10: 
ffff828bfff57008   r11: 0000000000000020
(XEN) r12: ffff830127fc80a0   r13: 
0000000000000090   r14: ffff830127fc80e0
(XEN) r15: ffff830127ff1540   cr0: 
000000008005003b   cr4: 00000000000026f0
(XEN) cr3: 00000000cfa6c000   cr2: 
ffff828bfff5aff8
(XEN) ds: 0000   es: 
0000   fs: 0000   gs: 
0000   ss: 0000   cs: e008
(XEN) Xen stack trace from rsp=ffff828c80267db8:
(XEN)    ffff828c80267df8 
ffff828c8012e6f2 ffff828c80267df8 0000000000000002
(XEN)    ffff830127fc8240 
ffff828c80216e90 ffff828c80267e18 ffff828c80216ec0
(XEN)    ffff828c80267e48 
ffff828c8012effc ffff828c80267e38 ffff828c8012a456
(XEN)    000000000000001f 
00000000ffffffed ffff828c80239e10 0000000000000001
(XEN)    ffff828c80218a60 
ffff828c80218960 ffff828c80267e68 ffff828c8012bb55
(XEN)    ffff828c80267e68 
ffff828c80239cf8 ffff828c80267f18 ffff828c8022d87c
(XEN)    0000000000000000 
0000000000000000 000000000008bf40 0000000000000000
(XEN)    0000000000000000 
ffff83000008bfc0 ffff83000008bf40 000000000163d108
(XEN)    0000000000000000 
ffffffff00000000 0000000800000000 000000010000006e
(XEN)    0000000000000003 
00000000000002f8 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000067e9c 
ffff828c801000b5 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)   
 0000000000000000 0000000000000000 0000000000000000 
0000000000000000
(XEN)    ffff8300ce1c0000
(XEN) Xen call trace:
(XEN)    
[<ffff828c8012db81>] clear_fault_bits+0x2d/0xb3
(XEN)    
[<ffff828c8012e6f2>] init_vtd_hw+0x2d7/0x3e9
(XEN)    
[<ffff828c8012effc>] intel_vtd_setup+0x51e/0x638
(XEN)    
[<ffff828c8012bb55>] iommu_setup+0x38/0xfd
(XEN)    
[<ffff828c8022d87c>] __start_xen+0x2456/0x273a
(XEN)
(XEN) Pagetable walk from ffff828bfff5aff8:
(XEN)  L4[0x105] = 00000000cfa72027 
5555555555555555
(XEN)  L3[0x02f] = 0000000127ffa063 
5555555555555555
(XEN)  L2[0x1ff] = 0000000127ff9063 
5555555555555555
(XEN)  L1[0x15a] = 0000000000000000 
ffffffffffffffff
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) FATAL PAGE FAULT
(XEN) [error_code=0000]
(XEN) Faulting linear address: ffff828bfff5aff8
(XEN) ****************************************
(XEN)
(XEN) Reboot in five seconds...
 
Various google searches yielded a similar seeming issue 
previously posted
http://www.nabble.com/Re:-Problem:-Xen-3.4-fails-to-boot-on-Dell-e6400,-with--iommu%3D1-p24250643.html
from the posts I attempted the described patches,
the first (print clear fault bits) yields the following 
change 
 
(XEN) Intel VT-d Snoop Control supported.
(XEN) Intel VT-d DMA Passthrough supported.
(XEN) Intel VT-d Queued Invalidation supported.
(XEN) Intel VT-d Interrupt Remapping supported.
(XEN) clear_fault_bits: CAP_REG=0xffffffffffffffff
(XEN) ----[ Xen-3.4.1-rc8  
x86_64  debug=y  Not tainted 
]----
(XEN) CPU:    0
(XEN) RIP:    
e008:[<ffff828c8012f000>] clear_fault_bits+0x5f/0xea
(XEN) RFLAGS: 0000000000010202   
CONTEXT: hypervisor
(XEN) rax: ffff828bfff5aff8   rbx: 
ffff830127ff1e90   rcx: 0000000000000000
(XEN) rdx: 00000000ffffffff   rsi: 
000000000000000a   rdi: ffff828bfff57000
(XEN) rbp: ffff828c80267db8   rsp: 
ffff828c80267da8   r8:  
ffff828bfff5700c
(XEN) r9:  
ffff828bfff57008   r10: 
00000000ffffffed   r11: 0000000000000010
(XEN) r12: ffff830127ff1e90   r13: 
0000000000000090   r14: ffff830127ff1ed0
(XEN) r15: ffff830127ff1540   cr0: 
000000008005003b   cr4: 00000000000026f0
(XEN) cr3: 00000000cfa6c000   cr2: 
ffff828bfff5aff8
(XEN) ds: 0000   es: 
0000   fs: 0000   gs: 
0000   ss: 0000   cs: e008
(XEN) Xen stack trace from rsp=ffff828c80267da8:
(XEN)    ffff830127ff1e90 
0000000000004090 ffff828c80267df8 ffff828c8012fa2a
(XEN)    ffff828c80267df8 
0000000000000002 ffff830127fe0070 ffff828c8021c690
(XEN)    ffff828c80267e18 
ffff828c8021c6c0 ffff828c80267e48 ffff828c80130334
(XEN)    ffff828c80267e38 
ffff828c8012b756 000000000000001f 00000000ffffffed
(XEN)    ffff828c8023ee30 
0000000000002000 ffff828c8021e260 ffff828c8021e160
(XEN)    ffff828c80267e68 
ffff828c8012ce55 ffff828c80267e68 ffff828c8023ed18
(XEN)    ffff828c80267f18 
ffff828c802328ac 0000000000000000 0000000000000000
(XEN)    000000000008bf10 
0000000000000000 0000000000000000 ffff83000008bfc0
(XEN)    ffff83000008bf10 
000000000169eb28 0000000000000000 ffffffff00000000
(XEN)    0000000800000000 
000000010000006e 0000000000000003 00000000000002f8
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000067e9c ffff828c801000b5
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 
0000000000000000 ffff8300cf8fc000
(XEN) Xen call trace:
(XEN)    
[<ffff828c8012f000>] clear_fault_bits+0x5f/0xea
(XEN)    
[<ffff828c8012fa2a>] init_vtd_hw+0x2d7/0x3e9
(XEN)    
[<ffff828c80130334>] intel_vtd_setup+0x51e/0x638
(XEN)    
[<ffff828c8012ce55>] iommu_setup+0x38/0xfd
(XEN)    
[<ffff828c802328ac>] __start_xen+0x2456/0x273a
(XEN)
(XEN) Pagetable walk from ffff828bfff5aff8:
(XEN)  L4[0x105] = 00000000cfa72027 
5555555555555555
(XEN)  L3[0x02f] = 0000000127ffa063 
5555555555555555
(XEN)  L2[0x1ff] = 0000000127ff9063 
5555555555555555
(XEN)  L1[0x15a] = 0000000000000000 
ffffffffffffffff
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) FATAL PAGE FAULT
(XEN) [error_code=0000]
(XEN) Faulting linear address: ffff828bfff5aff8
(XEN) ****************************************
(XEN)
(XEN) Reboot in five seconds...
 
And the second patch from the post (do not clear fault 
bits)
Gets us the following
 
(XEN) Intel VT-d Interrupt Remapping supported.
(XEN) DMAR_IQA_REG = ffffffffffffffff
(XEN) DMAR_IQH_REG = ffffffffffffffff
(XEN) DMAR_IQT_REG = ffffffffffffffff
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) queue invalidate wait descriptor was not 
executed
(XEN) ****************************************
(XEN)
(XEN) Reboot in five seconds...
 
Any ideas would be wonderfull as I would like to use 
passthrough with a windows hvm
Thank you
--Mike