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Groups > linux.kernel > #1740004
| From | Dan Williams <dan.j.williams@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU |
| Date | 2017-09-26 18:20 +0200 |
| Message-ID | <uu0Kt-732-5@gated-at.bofh.it> (permalink) |
| References | (4 earlier) <utGC7-1Kz-35@gated-at.bofh.it> <utP2G-7zs-13@gated-at.bofh.it> <utX9T-4JB-19@gated-at.bofh.it> <utZ22-5UA-7@gated-at.bofh.it> <uu0Kt-732-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Sep 26, 2017 at 9:06 AM, Casey Leedom <leedom@chelsio.com> wrote:
> | From: Robin Murphy <robin.murphy@arm.com>
> | Sent: Tuesday, September 26, 2017 7:22 AM
>
> |
> | On 26/09/17 13:21, Harsh Jain wrote:
> | > Find attached new set of log. After repeated tries it panics.
> |
> | Thanks, that makes things a bit clearer - looks like fixing the physical
> | address/pteval calculation to not be off by a page in one direction wasn't
> | helping much because the returned DMA address is actually also off by a
> | page in the other direction, and thus overflowing past the allocated IOVA
> | into whoever else's mapping happened to be there; complete carnage ensues.
> |
> | After another look through the intel_map_sg() path, here's my second
> (still
> | completely untested) guess at a possible fix.
> |
> | Robin.
> |
> | ----->8-----
> | diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> | index 6784a05dd6b2..d7f7def81613 100644
> | --- a/drivers/iommu/intel-iommu.c
> | +++ b/drivers/iommu/intel-iommu.c
> | @@ -2254,10 +2254,12 @@ static int __domain_mapping(struct dmar_domain
> *domain, unsigned long iov_pfn,
> | uint64_t tmp;
> |
> | if (!sg_res) {
> | + size_t off = sg->offset & ~PAGE_MASK;
> | +
> | sg_res = aligned_nrpages(sg->offset, sg->length);
> | - sg->dma_address = ((dma_addr_t)iov_pfn <<
> VTD_PAGE_SHIFT) + sg->offset;
> | + sg->dma_address = ((dma_addr_t)iov_pfn <<
> VTD_PAGE_SHIFT) + off;
> | sg->dma_length = sg->length;
> | - pteval = page_to_phys(sg_page(sg)) | prot;
> | + pteval = (page_to_phys(sg_page(sg)) + sg->offset -
> off) | prot;
> | phys_pfn = pteval >> VTD_PAGE_SHIFT;
> | }
>
> Thanks Robin. And thanks Harsh for sending the detailed trace logs. I'll
> see if I can get this tested today. Harsh is probably headed towards bed,
> but there may be sufficiently good instructions in our internal bug system
> to reproduce the issue.
>
> Regardless, it seems that you agree that there's an issue with the Intel
> I/O MMU support code with regard to the legal values which a (struct
> scatterlist) can take on? I still can't find any documentation for this
> and, personally, I'm a bit baffled by a Page-oriented Scatter/Gather List
> representation where [Offset, Offset+Length) can reside outside the Page.
Consider the case where the page represents a huge page, then an
offset greater than PAGE_SIZE (up to HPAGE_SIZE) makes sense.
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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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