Re: [ 102/127] iommu/amd: Workaround for ERBT1312

[Joerg Roedel <joro@8bytes.org>]

Hi Andreas,

On Fri, Jun 28, 2013 at 06:11:36PM +0200, Andreas Hartmann wrote:
> Hello Joerg, hello Alex,
> 
> the subsequent patch and the patch "iommu/amd: Re-enable IOMMU event log
> interrupt after handling." 925fe08bce38d1ff052fe2209b9e2b8d5fbb7f98
> spread /var/log/messages with the following line (> 700 lines/second)
> right after loading vfio:
> 
> AMD-Vi: Event logged [IO_PAGE_FAULT device=00:14.0 domain=0x0000 address=0x000000fdf9103300 flags=0x0600]
> 
> lspci -vvvs 0:14.0
> 00:14.0 SMBus: Advanced Micro Devices [AMD] nee ATI SBx00 SMBus Controller (rev 42)
>         Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
>         Status: Cap- 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-

Most likely a BIOS issue that is uncovered by re-enabling the event-log
interrupt patch. The device itself is only used by the BIOS and not by
the Linux kernel

> Besides the enormous pollution I couldn't see any malfunction at all.
> At first, I didn't realised it at all (-> the SSD was fast enough to
> cover it silently). I saw it the first time I rebooted because X didn't start any more because
> the /var partition was completely full. 
> 
> I removed the two mentioned patches and all is working
> fine again as before.

Without these two patches, can you check dmesg after boot if there are
other lines which report IO_PAGE_FAULTs?


	Joerg