Messages in this thread | | | Date | Fri, 26 Sep 2008 17:47:08 +0300 | From | Muli Ben-Yehuda <> | Subject | Re: bad DMAR interaction with iwlagn and SATA |
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On Thu, Sep 25, 2008 at 10:41:04PM -0400, Jeff Garzik wrote: > Andres Freund wrote: >> Hi Jeff, >> On Friday 26 September 2008, you wrote in "Re: bad DMAR interaction with >> iwlagn and SATA": >>> Andres Freund wrote: >>>> sleeping I activated DMAR... >>>> .. >>>> Second: >>>> [ 2937.484251] DMAR:[DMA Read] Request device [00:1f.2] fault addr >>>> fffbf000 [ 2937.484255] DMAR:[fault reason 06] PTE Read access is not >>>> set >>>> [ 2937.484297] ata1.00: exception Emask 0x60 SAct 0x1 SErr 0x800 action >>>> 0x6 frozen >>>> [ 2937.484303] ata1.00: irq_stat 0x20000000, host bus error >>>> [ 2937.484309] ata1: SError: { HostInt } >>>> [ 2937.484319] ata1.00: cmd 61/08:00:c0:1d:6b/00:00:07:00:00/40 tag 0 >>>> ncq >>>> 4096 out >>>> [ 2937.484321] res 40/00:00:c0:1d:6b/00:00:07:00:00/40 Emask >>>> 0x60 (host bus error) >>> Ouch, a host bus error is serious nastiness... >> I only hit that with DMAR activated (hit it twice, different boots), so it >> seems to be related to that. Is there anything I can help to debug that? > > No idea about DMAR. On the ATA side, it pretty diagnoses itself as > you see here. Unfortunately, ATA controller is behaving exactly as > it should, when a major system error is thrown its way.
The way to debug this is to figure out why device 00:1f.2 is trying to read from DMA address fffbf000 and does not have permission to do so. This could be indicative of a driver bug where it is programming the device to read from some buffer that has not been allocated through the DMA API and thus does not have a valid IOMMU mapping, or a hardware quirk where the device tries to read from memory without host involvement. The former is much more likely.
Cheers, Muli -- The First Workshop on I/O Virtualization (WIOV '08) Dec 2008, San Diego, CA, http://www.usenix.org/wiov08/ xxx SYSTOR 2009---The Israeli Experimental Systems Conference http://www.haifa.il.ibm.com/conferences/systor2009/
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