On 2020-09-22 3:51 a.m., Robin Murphy wrote: > On 2020-09-18 21:47, Logan Gunthorpe wrote: >> Hi Lu, >> >> On 2020-09-11 9:21 p.m., Lu Baolu wrote: >>> Tom Murphy has almost done all the work. His latest patch series was >>> posted here. >>> >>> https://lore.kernel.org/linux-iommu/20200903201839.7327-1-murphyt7@xxxxxx/ >>> >>> Thanks a lot! >>> >>> This series is a follow-up with below changes: >>> >>> 1. Add a quirk for the i915 driver issue described in Tom's cover >>> letter. >>> 2. Fix several bugs in patch "iommu: Allow the dma-iommu api to use >>> bounce buffers" to make the bounce buffer work for untrusted devices. >>> 3. Several cleanups in iommu/vt-d driver after the conversion. >>> >> >> I'm trying to test this on an old Sandy Bridge, but found that I get >> spammed with warnings on boot. I've put a sample of a few of them below. >> They all seem to be related to ioat. >> >> I had the same issue with Tom's v2 but never saw this on his v1. > > I think this might have more to do with ioat being totally broken - > AFAICS it appears to allocate descriptors with a size of 2MB, but free > them with a size of 512KB. Try throwing CONFIG_DMA_API_DEBUG at it to > confirm. Ah, yes, nice catch. Looks like it was broken recently by the following commit, but nobody noticed and the dma-iommu patch set added a warning which caught it. a02254f8a676 ("dmaengine: ioat: Decreasing allocation chunk size 2M->512K") Reverting that fixes the issue. I'll try to send patch or two for this. Logan _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
