Re: VT-d faults with Integrated Intel graphics on 4.6

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 8/25/2015 8:19 AM, Tamas K Lengyel wrote:
> Hi everyone,
> I saw some people passingly mention this on the list before but just in
> case it has been missed, my serial is also being spammed with the following
> printouts with both Xen 4.6 RC1 and the latest staging build:
>
> ...
> (XEN) [VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr
> 33487d7000, iommu reg = ffff82c000201000
> (XEN) [VT-D]DMAR: reason 06 - PTE Read access is not set
> (XEN) [VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr
> 33487d7000, iommu reg = ffff82c000201000
> (XEN) [VT-D]DMAR: reason 06 - PTE Read access is not set
> (XEN) [VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr
> 33487d7000, iommu reg = ffff82c000201000
> (XEN) [VT-D]DMAR: reason 06 - PTE Read access is not set
> (XEN) [VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr
> 33487d7000, iommu reg = ffff82c000201000
> (XEN) [VT-D]DMAR: reason 06 - PTE Read access is not set
> (XEN) [VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr
> 2610742000, iommu reg = ffff82c000201000
> (XEN) [VT-D]DMAR: reason 07 - Next page table ptr is invalid
> ...
>

What's your platform? BDW? And how much memory is set to your guest OS?

Just at first glance to fault address, this seems be issued from some 
known erratas on BDS and SKL.

Thanks
Tiejun

> The device in question is an integrated Intel graphics card:
>
> 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core
> Processor Family Integrated Graphics Controller (rev 09)
>
> The only way I found to stop the messages from making my serial connection
> useless was by assigning the device to xen-pciback.
>
> Cheers,
> Tamas
>
>
>
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