Re: [Xen-devel] fail to detect VT-D on Dell (optiplex 760)

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Andrew Cooper wrote on 2013-07-31:
> On 31/07/13 12:13, Dennis Lan (dlan) wrote:
>> HI Devs:
>>  I have problem to boot with VT-D enabled on my machine, with
>> Xen-4.3.0, it just hangs[0]. But with 4.4-unstable version, it boot
>> successfully but still fail to detect iommu.
>> 
>> I'm using xen-git master branch,commit:
>> 6072b7c808043b6886c33f896e06fc32ee28346e
>> 
>> also you can refer [1] for more information.
>> interesting bits from xen-4.4-unstable, full log is here[2]
>> 
>> (XEN) vmap(ffff82c000201000:0x1)
>> (XEN) [VT-D]iommu.c:1167: IOMMU: unsupported
>> (XEN) ---- print_iommu_regs ----
>> (XEN)  drhd->address = fedc1000
>> (XEN)  VER = ffffffff
>> (XEN)  CAP = ffffffffffffffff
>> (XEN)  n_fault_reg = 100
>> (XEN)  fault_recording_offset = 3ff0
>> (XEN)  ECAP = ffffffffffffffff
>> (XEN)  GCMD = ffffffff
>> (XEN)  GSTS = ffffffff
>> (XEN)  RTADDR = ffffffffffffffff
>> (XEN)  CCMD = ffffffffffffffff
>> (XEN)  FSTS = ffffffff
>> (XEN)  FECTL = ffffffff
>> (XEN)  FEDATA = ffffffff
>> (XEN)  FEADDR = ffffffff
>> (XEN)  FEUADDR = ffffffff
>> (XEN) vunmap(ffff82c000201000:0x1)
>> (XEN) Failed to parse ACPI DMAR.  Disabling VT-d.
>> (XEN) ERST table was not found
>> (XEN) Using ACPI (MADT) for SMP configuration information
> 
> According to this, the DMAR table is problematic.  This is the ACPI
> table which describes the IOMMU functionality.  Do you have a BIOS upgrade 
> available?
Yes, the ACPI table is broken. It's better to dump the DMAR to have a double 
chek.
 
>> 
>> btw, Ian, I also keep you CCed.
>> 
>> [0] https://bugs.gentoo.org/show_bug.cgi?id=479082#c3
>> [1] https://bugs.gentoo.org/show_bug.cgi?id=479082
>> [2] https://479082.bugs.gentoo.org/attachment.cgi?id=354706
>> 
>> Dennis Lan (dlan)
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxx
>> http://lists.xen.org/xen-devel
> 
> 
> _______________________________________________
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> http://lists.xen.org/xen-devel


Best regards,
Yang



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