On Tue, 29 Sep 2015, Joerg Roedel wrote: > On Sun, Sep 20, 2015 at 08:50:40AM +0200, Andreas Hartmann wrote: > > > I would submit this bug to maintainers of AMD-Vi. They understand the > > > hardware, so they should tell why do large I/O requests result in > > > IO_PAGE_FAULTs. > > > > > > It is probably bug either in AMD-Vi driver or in hardware. > > > > Until now, I didn't hear anything from the maintainers of AMD-Vi. > > What do you mean by this? I've been commenting on this issue in the > past and I thought we agreed that this is no issue of the IOMMU driver. > > It it were, bisection should lead to a commit that breaks it, but there > are no commits between v3.18 and v3.19 in the AMD IOMMU driver touching > the DMA-API path. > > Joerg I don't know why are you so certain that the bug in not in AMD-Vi IOMMU. There was a patch (34b48db66e08ca1c1bc07cf305d672ac940268dc) that increased default block request size. That patch triggers AMD-Vi page faults. The bug may be in ATA driver, in ATA controller on in AMD-Vi driver or hardware. I didn't see anything in that thread that proves that the bug in not in AMD-Vi IOMMU. The bug probably existed even before kernel 3.19, but it was masked by the fact that I/O request size was artifically capped. Bisecting probably won't find it, as it may have existed since ever. Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
