Messages in this thread | | | From | Casey Leedom <> | Subject | Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU | Date | Wed, 27 Sep 2017 21:29:23 +0000 |
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Hey Raj,
Let us know if you need help in gathering more debugging information. For the time being we've decided to ERRATA the use of the Intel I/O MMU with IPsec till we Root Cause the issue. But this is still at the top of Harsh's bug list.
With Robin's comments, I'm almost sure that the:
(iov_pfn + sg->offset) << VTD_PAGE_SHIFT)
in your suggested patch is an issue. iov_pfn is a Page Frame Number and sg->offset is a Byte Offset. It feels like this should be:
size_t page_off = sg->offset & ~VTD_PAGE_MASK; unsigned long pfn_off = sg->offset >> VTD_PAGE_MASK; ... sg->dma_address = ((dma_addr_t) (iov_pfn + pfn_off) << VTD_PAGE_SHIFT) + page_off;
When Harsh tried your original patch, Harsh' test system wouldn't even boot.
Casey
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