Hi,
Well, just tried what you suggested, and here are 
    the results:
* If i comment the 'clear_fault_bits()' call - then Xen 
    boots ok, with iommu=1
The strange thing, is that after it booted one 
    time ok (with the second patch), then it continued to boot ok, even if i 
    reverted the second patch.
The relevant lines in the log 
    are:
(XEN) clear_fault_bits: CAP_REG=0xc0000020630270
(XEN) 
    clear_fault_bits: CAP_REG=0xc0000020630260
(XEN) clear_fault_bits: 
    CAP_REG=0xc9008020e30260
(XEN) clear_fault_bits: 
    CAP_REG=0xc9008020630260
Anyway, here is the full Xen log, with the 
    first patch (print cap's) applied:
__  
    __            _____ 
    _  _    ___  
 \ \/ /___ _ __   
    |___ /| || |  / _ \ 
  \  // _ \ '_ \    |_ 
    \| || |_| | | |
  /  \  __/ | | |  ___) 
    |__   _| |_| |
 /_/\_\___|_| |_| |____(_) |_|(_)___/ 
                                          
    
(XEN) Xen version 3.4.0 (root@[unknown]) (gcc version 4.3.2 (Debian 
    4.3.2-1.1) ) Mon Jun 29 07:53:38 EDT 2009
(XEN) Latest ChangeSet: Wed Jun 
    24 11:15:04 2009 +0300 19629:b2128a88e3dd
(XEN) Command line: 
    console=com1 com1=115200,8n1 iommu=1 iommu_inclusive_mapping loglvl=all 
    guest_loglvl=all
(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 - 000000000009f000 
    (usable)
(XEN)  000000000009f000 - 00000000000a0000 
    (reserved)
(XEN)  0000000000100000 - 000000007c04d400 
    (usable)
(XEN)  000000007c04d400 - 000000007c04f400 (ACPI 
    NVS)
(XEN)  000000007c04f400 - 000000007f000000 
    (reserved)
(XEN)  00000000f8000000 - 00000000fc000000 
    (reserved)
(XEN)  00000000fec00000 - 00000000fec10000 
    (reserved)
(XEN)  00000000fed18000 - 00000000fed1c000 
    (reserved)
(XEN)  00000000fed20000 - 00000000fed90000 
    (reserved)
(XEN)  00000000feda0000 - 00000000feda6000 
    (reserved)
(XEN)  00000000fee00000 - 00000000fee10000 
    (reserved)
(XEN)  00000000ffe60000 - 0000000100000000 
    (reserved)
(XEN) System RAM: 1983MB (2031536kB)
(XEN) ACPI: RSDP 
    000FB9C0, 0024 (r2 DELL  )
(XEN) ACPI: XSDT 7C051E00, 006C (r1 
    DELL    M09     27D9020D 
    ASL        61)
(XEN) ACPI: FACP 
    7C051C9C, 00F4 (r4 DELL    M09     
    27D9020D ASL        61)
(XEN) ACPI: 
    DSDT 7C052400, 6A2B (r2 INT430 SYSFexxx     1001 INTL 
    20050624)
(XEN) ACPI: FACS 7C060C00, 0040
(XEN) ACPI: HPET 7C051F00, 
    0038 (r1 DELL    
    M09            1 
    ASL        61)
(XEN) ACPI: DMAR 
    7C060400, 0120 (r1 DELL    M09     
    27D9020D ASL        61)
(XEN) ACPI: 
    APIC 7C052000, 0068 (r1 DELL    M09     
    27D9020D ASL        47)
(XEN) ACPI: 
    ASF! 7C051C00, 006A (r32 DELL    M09     
    27D9020D ASL        61)
(XEN) ACPI: 
    MCFG 7C051FC0, 003E (r16 DELL    M09     
    27D9020D ASL        61)
(XEN) ACPI: 
    TCPA 7C052300, 0032 
    (r1                        
    0 ASL         0)
(XEN) ACPI: SLIC 
    7C05209C, 0176 (r1 DELL    M09     
    27D9020D ASL        61)
(XEN) ACPI: 
    SSDT 7C05032D, 066C (r1  PmRef    
    CpuPm     3000 INTL 20050624)
(XEN) NUMA turned 
    off
(XEN) Faking a node at 0000000000000000-000000007c04d000
(XEN) 
    Domain heap initialised
(XEN) DMI 2.4 present.
(XEN) Using APIC driver 
    default
(XEN) ACPI: PM-Timer IO Port: 0x1008
(XEN) ACPI: ACPI SLEEP 
    INFO: pm1x_cnt[1004,0], pm1x_evt[1000,0]
(XEN) 
    ACPI:                  
    wakeup_vec[7c060c0c], vec_size[20]
(XEN) ACPI: Local APIC address 
    0xfee00000
(XEN) ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] 
    enabled)
(XEN) Processor #0 7:7 APIC version 20
(XEN) ACPI: LAPIC 
    (acpi_id[0x01] lapic_id[0x01] enabled)
(XEN) Processor #1 7:7 APIC 
    version 20
(XEN) ACPI: LAPIC_NMI (acpi_id[0x00] high edge 
    lint[0x1])
(XEN) ACPI: LAPIC_NMI (acpi_id[0x01] high edge 
    lint[0x1])
(XEN) ACPI: IOAPIC (id[0x02] address[0xfec00000] 
    gsi_base[0])
(XEN) IOAPIC[0]: apic_id 2, 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: 0x8086a201 
    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 = fed10000
(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 = fed11000
(XEN) [VT-D]dmar.c:300: 
    found endpoint: bdf = 0:2.0
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 
    0:2.1
(XEN) [VT-D]dmar.c:494: found ACPI_DMAR_DRHD
(XEN) 
    [VT-D]dmar.c:349: dmaru->address = fed12000
(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 = fed13000
(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) 
    [VT-D]dmar.c:498: found ACPI_DMAR_RMRR
(XEN) [VT-D]dmar.c:300: found 
    endpoint: bdf = 0:2.0
(XEN) [VT-D]dmar.c:300: found endpoint: bdf = 
    0:2.1
(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 
    2527.068 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) mce_init: init bank1
(XEN) mce_init: 
    init bank2
(XEN) mce_init: init bank3
(XEN) mce_init: init 
    bank4
(XEN) mce_init: init bank5
(XEN) CPU0: Thermal monitoring 
    enabled (TM2)
(XEN) CMCI: CPU0 has no CMCI support
(XEN) CPU0: 
    Intel(R) Core(TM)2 Duo CPU     T9400  @ 2.53GHz 
    stepping 06
(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) 
    mce_init: init bank1
(XEN) mce_init: init bank2
(XEN) mce_init: init 
    bank4
(XEN) mce_init: init bank5
(XEN) CPU1: Thermal monitoring 
    enabled (TM2)
(XEN) CMCI: CPU1 has no CMCI support
(XEN) CPU1: 
    Intel(R) Core(TM)2 Duo CPU     T9400  @ 2.53GHz 
    stepping 06
(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) [VT-D]iommu.c:1763: DMAR: Forcing write-buffer 
    flush
(XEN) Intel VT-d Snoop Control not supported.
(XEN) Intel VT-d 
    DMA Passthrough not supported.
(XEN) Intel VT-d Queued Invalidation not 
    supported.
(XEN) Intel VT-d Interrupt Remapping not supported.
(XEN) 
    clear_fault_bits: CAP_REG=0xc0000020630270
(XEN) clear_fault_bits: 
    CAP_REG=0xc0000020630260
(XEN) clear_fault_bits: 
    CAP_REG=0xc9008020e30260
(XEN) clear_fault_bits: 
    CAP_REG=0xc9008020630260
(XEN) I/O virtualisation enabled
(XEN) I/O 
    virtualisation for PV guests disabled
(XEN) HPET: 4 timers in total, 0 
    timers will be used for broadcast
(XEN) ACPI sleep modes: S3
(XEN) 
    mcheck_poll: Machine check polling timer started.
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:0.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:2.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:2.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:3.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:3.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:3.3
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:19.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.7
(XEN) 
    [VT-D]iommu.c:1245:d32767 domain_context_mapping:PCIe: bdf = 0:1b.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.7
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1f.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1f.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1f.3
(XEN) 
    [VT-D]iommu.c:1245:d32767 domain_context_mapping:PCIe: bdf = c:0.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:2.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:2.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1d.7
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.0
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.1
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.2
(XEN) 
    [VT-D]iommu.c:1252:d32767 domain_context_mapping:PCI: bdf = 0:1a.7
(XEN) 
    [VT-D]iommu.c:620: iommu_enable_translation: iommu->reg = 
    ffff828bfff57000
(XEN) [VT-D]iommu.c:620: iommu_enable_translation: 
    iommu->reg = ffff828bfff56000
(XEN) [VT-D]iommu.c:620: 
    iommu_enable_translation: iommu->reg = ffff828bfff55000
(XEN) 
    [VT-D]iommu.c:620: iommu_enable_translation: iommu->reg = 
    ffff828bfff54000
(XEN) *** LOADING DOMAIN 0 ***
(XEN)  Xen  
    kernel: 64-bit, lsb, compat32
(XEN)  Dom0 kernel: 64-bit, lsb, paddr 
    0xffffffff80200000 -> 0xffffffff8070ab48
(XEN) PHYSICAL MEMORY 
    ARRANGEMENT:
(XEN)  Dom0 alloc.:   
    0000000076000000->0000000078000000 (460259 pages to be 
    allocated)
(XEN) VIRTUAL MEMORY ARRANGEMENT:
(XEN)  Loaded 
    kernel: ffffffff80200000->ffffffff8070ab48
(XEN)  Init. ramdisk: 
    ffffffff8070b000->ffffffff81b94400
(XEN)  Phys-Mach map: 
    ffffffff81b95000->ffffffff81f27f18
(XEN)  Start 
    info:    ffffffff81f28000->ffffffff81f284b4
(XEN)  
    Page tables:   
    ffffffff81f29000->ffffffff81f3c000
(XEN)  Boot 
    stack:    
    ffffffff81f3c000->ffffffff81f3d000
(XEN)  
    TOTAL:         
    ffffffff80000000->ffffffff82000000
(XEN)  ENTRY ADDRESS: 
    ffffffff80200000
(XEN) Dom0 has maximum 2 VCPUs
(XEN) Scrubbing Free 
    RAM: .done.
(XEN) Xen trace buffers: disabled
(XEN) Std. Loglevel: 
    All
(XEN) Guest Loglevel: All
(XEN) *** Serial input -> DOM0 (type 
    'CTRL-a' three times to switch input to Xen)
(XEN) Freed 132kB init 
    memory.
Tom
    
2009/6/29 Cui, Dexuan 
<dexuan.cui@xxxxxxxxx>
    
      diff -r 90391e2247fc xen/drivers/passthrough/vtd/iommu.c
--- 
      a/xen/drivers/passthrough/vtd/iommu.c   Tue Jun 23 11:40:27 2009 
      +0100
+++ b/xen/drivers/passthrough/vtd/iommu.c   Mon Jun 29 
      10:24:31 2009 +0800
@@ -1693,7 +1693,7 @@ static int 
      init_vtd_hw(void)
        }
      
        dma_msi_data_init(iommu, iommu->vector);
      
        dma_msi_addr_init(iommu, 
      cpu_physical_id(first_cpu(cpu_online_map)));
-       
       clear_fault_bits(iommu);
+       
       //clear_fault_bits(iommu);
        
      dmar_writel(iommu->reg, DMAR_FECTL_REG, 0);
      
        /* initialize flush functions */
And, can you comment the 
      invocation of clear_fault_bits() in init_vtd_hw() like above and see if 
      the host can boot fine?
Thanks,
-- 
      Dexuan
      -----Original Message-----
From: Cui, Dexuan
Sent: 
      2009?6?29? 14:30
To: 'Tom Rotenberg'; 
xen-devel@xxxxxxxxxxxxxxxxxxxSubject: RE: 
      [Xen-devel] Problem: Xen 3.4 fails to boot on Dell e6400, with 
      iommu=1
diff -r 90391e2247fc 
      xen/drivers/passthrough/vtd/iommu.c
--- 
      a/xen/drivers/passthrough/vtd/iommu.c   Tue Jun 23 11:40:27 2009 
      +0100
+++ b/xen/drivers/passthrough/vtd/iommu.c   Mon Jun 29 
      10:18:23 2009 +0800
@@ -1653,6 +1653,8 @@ void clear_fault_bits(struct 
      iommu *iomm
 {
    u64 val;
+   
       printk("clear_fault_bits: CAP_REG=0x%llx\n",
+     
         (unsigned long 
      long)dmar_readq(iommu->reg,DMAR_CAP_REG));
    val = 
      dmar_readq(
        iommu->reg,
    
          
      cap_fault_reg_offset(dmar_readq(iommu->reg,DMAR_CAP_REG))+0x8);
Hi 
      Tom,
Can you please apply the above patch and send us the entire 
      log?
(I don't have the same host, so I can't try it 
      myself.)
Thanks,
-- 
      Dexuan
________________________________
From: 
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Tom 
      Rotenberg
Sent: 2009?6?28? 22:56
To: 
xen-devel@xxxxxxxxxxxxxxxxxxxSubject: [Xen-devel] 
      Problem: Xen 3.4 fails to boot on Dell e6400, with 
      iommu=1
 
      
      
      Hi,
I am trying to use xen 3.4 on a Dell E6400 machine. But, 
      when i try to boot xen with a 'iommu=1' parameter in the boot line, Xen 
      fails to boot. I have also tried to boot with and without the 
      'iommu_inclusive_mapping' boot option, but it didn't seem to help at 
      all.
Does anyone knows how to solve this issue?
These are 
      the last messages in the UART:
(XEN) Brought up 2 CPUs
(XEN) 
      microcode.c:73:d32767 microcode: CPU1 resumed
(XEN) [VT-D]iommu.c:1761: 
      DMAR: Forcing write-buffer flush
(XEN) Intel VT-d Snoop Control 
      supported.
(XEN) Intel VT-d DMA Passthrough not supported.
(XEN) 
      Intel VT-d Queued Invalidation supported.
(XEN) Intel VT-d Interrupt 
      Remapping supported.
(XEN) ----[ Xen-3.4.0  x86_64  debug=n 
       Not tainted ]----
(XEN) CPU:    0
(XEN) RIP:   
       e008:[<ffff828c8012c951>] clear_fault_bits+0x21/0xa0
(XEN) 
      RFLAGS: 0000000000010202   CONTEXT: hypervisor
(XEN) rax: 
      ffff828bfff5aff8   rbx: ffff830078f82f90   rcx: 
      0000000000000020
(XEN) rdx: 00000000ffffffff   rsi: 
      ffff828bfff57000   rdi: ffff830078f82f90
(XEN) rbp: 
      0000000000000090   rsp: ffff828c8026fda0   r8: 
       ffff83007be2c110
(XEN) r9:  000000000000001a   r10: 
      0000000000000005   r11: 0000000000000005
(XEN) r12: 
      0000000000000090   r13: 0000000000000090   r14: 
      ffff830078f82fcc
(XEN) r15: 0000000000004800   cr0: 
      000000008005003b   cr4: 00000000000026f0
(XEN) cr3: 
      000000007be74000   cr2: ffff828bfff5aff8
(XEN) ds: 0000   es: 
      0000   fs: 0000   gs: 0000   ss: 0000   cs: 
      e008
(XEN) Xen stack trace from rsp=ffff828c8026fda0:
(XEN)   
       ffff828c8012d32d ffff830078f824b0 ffff828c801e422f 
      ffff828c80204490
(XEN)    ffff828c801e422f ffff828c802044c0 
      ffff828c8026fdf8 0000000000000000
(XEN)    ffff828c8012de7e 
      ffff830078f82d40 ffff828c80228100 000000000000001f
(XEN)   
       00000000ffffffed ffff828c80227a78 0000000000000001 
      ffff828c80205f60
(XEN)    ffff828c801f3400 ffff83000008bf40 
      ffff828c8012a9d4 ffff828c80227978
(XEN)    ffff828c8021a589 
      0000000000000000 0000000000000000 0000000000000000
(XEN)   
       0000000000000000 0000000000000000 0000000000000000 
      0000000000000000
(XEN)    00000000002b23c0 ffffff8c80274000 
      0008bf4000000000 000000000008bf40
(XEN)    0000000000000000 
      ffff83000008bfc0 0000000001ce08a0 0000000000000000
(XEN)   
       ffffffff00000000 0000000800000000 000000010000006e 
      0000000000000003
(XEN)    00000000000002f8 0000000000000000 
      0000000000000000 0000000000067e2c
(XEN)    0000000000000000 
      0000000000000000 0000000000000000 0000000000000000
(XEN)   
       ffff828c801000b5 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 0000000000000000 
      ffff830079f18000
(XEN) Xen call trace:
(XEN)   
       [<ffff828c8012c951>] clear_fault_bits+0x21/0xa0
(XEN) 
         [<ffff828c8012d32d>] init_vtd_hw+0x15d/0x3e0
(XEN) 
         [<ffff828c8012de7e>] 
      intel_vtd_setup+0x5ae/0x610
(XEN)   
       [<ffff828c8012a9d4>] iommu_setup+0x24/0x110
(XEN)   
       [<ffff828c8021a589>] __start_xen+0x1859/0x27c0
(XEN)   
       [<ffff828c801000b5>] __high_start+0xa1/0xa3
(XEN)
(XEN) 
      Pagetable walk from ffff828bfff5aff8:
(XEN)  L4[0x105] = 
      000000007be7a027 5555555555555555
(XEN)  L3[0x02f] = 
      000000007c04b063 5555555555555555
(XEN)  L2[0x1ff] = 
      000000007c04a063 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...