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...