After enable MSI option,  disk offline still appear, the attachment is the Call Trace.
           CPU0       CPU1       
  1:          2          0  xen-pirq-ioapic-edge  i8042
  4:          9          0  xen-pirq-ioapic-edge  serial
  8:          0          0  xen-pirq-ioapic-edge  rtc0
  9:          0          0  xen-pirq-ioapic-level  acpi
 12:          4          0  xen-pirq-ioapic-edge  i8042
 16:         34          0  xen-pirq-ioapic-level  uhci_hcd:usb3
 18:          2          0  xen-pirq-ioapic-level  ehci_hcd:usb1, uhci_hcd:usb6
 19:          0          0  xen-pirq-ioapic-level  uhci_hcd:usb5, ata_piix, ata_piix
 23:          0          0  xen-pirq-ioapic-level  ehci_hcd:usb2, uhci_hcd:usb4
482:          0          0   xen-dyn-event     evtchn:xenstored
483:         47        272   xen-dyn-event     evtchn:xenstored
490:    2957623       2181  xen-pirq-msi-x     peth0-2
491:    3239519       2907  xen-pirq-msi-x     peth0-1
492:    6678288          0  xen-pirq-msi-x     peth0-0
493:     134441         80  xen-pirq-msi       ioc0
495:          0          0   xen-dyn-virq      mce
500:          0          0   xen-dyn-virq      pcpu
501:         72        344   xen-dyn-event     xenbus
502:          0      43586   xen-dyn-ipi       callfuncsingle1
503:          0          0   xen-dyn-virq      debug1
504:          0          0   xen-dyn-ipi       callfunc1
505:          0     468438   xen-dyn-ipi       resched1
506:          0  148914934   xen-dyn-virq      timer1
507:      41098          0   xen-dyn-ipi       callfuncsingle0
508:          0          0   xen-dyn-virq      debug0
509:          0          0   xen-dyn-ipi       callfunc0
510:     502029          0   xen-dyn-ipi       resched0
511:  148977732          0   xen-dyn-virq      timer0
NMI:          0          0   Non-maskable interrupts
LOC:          0          0   Local timer interrupts
SPU:          0          0   Spurious interrupts
CNT:          0          0   Performance counter interrupts
PND:          0          0   Performance pending work
RES:     502029     468438   Rescheduling interrupts
CAL:      41098      43586   Function call interrupts
TLB:          0          0   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
MCE:          0          0   Machine check exceptions
MCP:        497        497   Machine check polls
ERR:          0
MIS:          0
Thanks.
Tsk
2010/4/28 Konrad Rzeszutek Wilk 
<konrad.wilk@xxxxxxxxxx>
On Wed, Apr 28, 2010 at 09:27:30PM +0800, yingbin wang wrote:
> we found some info from xen wiki:
>
> Enabling MSI/MSI-X for Assigned Devices
> As of Xen 3.4.0 MSI/MSI-X is always on.
>       This change was made in changeset: 18454:65dc37be0443
> In Xen 3.3.0, MSI/MSI-X could be enabled using the xen boot parameter "msi=1".
>       This change was made in changeset: 18127:89d05940cc1c
>       The following snippet from a grub configuration enables MSI/MSI-X
>               kernel xen.gz msi=1
>
> does it mean that we should also Enable MSI Support for SAS in mptbase module?
First try the iommu option (iommu=off for example) and also the x2apic=off
Do include your serial log so we can see what kind of error you are
getting. And also include you /proc/interrupts output please.