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

From	Harsh Jain <Harsh@chelsio.com>
Newsgroups	linux.kernel
Subject	Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU
Date	2017-09-26 13:20 +0200
Message-ID	<utW4a-42r-15@gated-at.bofh.it> (permalink)
References	<urIf0-kT-3@gated-at.bofh.it> <utGC6-1Kz-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 26-09-2017 00:15, David Woodhouse wrote:
> On Wed, 2017-09-20 at 16:01 +0800, Herbert Xu wrote:
>> Harsh Jain <Harsh@chelsio.com> wrote:
>>>  
>>> While debugging DMA mapping error in chelsio crypto driver we
>> observed that when scatter/gather list received by driver has some
>> entry with page->offset > 4096 (PAGE_SIZE). It starts giving DMA
>> error.  Without IOMMU it works fine.
>>
>> This is not a bug.  The network stack can and will feed us such
>> SG lists.
> Hm? Under what circumstances is the offset permitted to be >
> PAGE_SIZE? 
Its random, Kernel API's don't check offset value after arithmetic operations like in "__skb_to_sgvec()", "scatterwalk_ffwd()".

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DMA error when sg->offset value is greater than PAGE_SIZE in Intel  IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-16 08:20 +0200
  Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Herbert Xu <herbert@gondor.apana.org.au> - 2017-09-20 10:10 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Robin Murphy <robin.murphy@arm.com> - 2017-09-20 12:20 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-20 13:30 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 19:50 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-25 20:50 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 20:50 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 05:50 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 14:30 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Robin Murphy <robin.murphy@arm.com> - 2017-09-26 16:30 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-26 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
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-26 19:30 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-26 23:00 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-26 19:30 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Robin Murphy <robin.murphy@arm.com> - 2017-09-26 20:20 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-26 19:40 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-25 21:40 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 22:10 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-25 22:20 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-25 23:50 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-26 01:50 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 15:10 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-20 13:40 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU David Woodhouse <dwmw2@infradead.org> - 2017-09-25 20:50 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 22:20 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 13:20 +0200

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