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Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU

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On 28-09-2017 02:59, Casey Leedom wrote:
> 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.
Today I tried with "Intel_iommu=sp_off" boot option. Traffic runs without any error for more than 1 hrs. What magic this option did? :)
>
> Casey

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Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-26 18:20 +0200
  Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-27 18:40 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-27 19:20 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Christoph Hellwig <hch@infradead.org> - 2017-10-01 11:00 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-27 19:50 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-27 23:30 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-28 00:10 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-28 00:20 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-28 07:10 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Herbert Xu <herbert@gondor.apana.org.au> - 2017-09-28 12:40 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-28 15:40 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-28 18:10 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-29 07:40 +0200
  Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-27 19:40 +0200

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