diff options
| author | Robin Murphy <robin.murphy@arm.com> | 2017-09-28 15:14:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-16 10:33:49 +0100 |
| commit | dc41b6e35f9379399443785165cba97e1f46ab37 (patch) | |
| tree | 554099b2b6d1cf20d15517235fae1ecb022775e8 /drivers | |
| parent | 90a20a81dc1c05ceb8dc215d9e475b5cc66241a8 (diff) | |
iommu/vt-d: Fix scatterlist offset handling
commit 29a90b70893817e2f2bb3cea40a29f5308e21b21 upstream.
The intel-iommu DMA ops fail to correctly handle scatterlists where
sg->offset is greater than PAGE_SIZE - the IOVA allocation is computed
appropriately based on the page-aligned portion of the offset, but the
mapping is set up relative to sg->page, which means it fails to actually
cover the whole buffer (and in the worst case doesn't cover it at all):
(sg->dma_address + sg->dma_len) ----+
sg->dma_address ---------+ |
iov_pfn------+ | |
| | |
v v v
iova: a b c d e f
|--------|--------|--------|--------|--------|
<...calculated....>
[_____mapped______]
pfn: 0 1 2 3 4 5
|--------|--------|--------|--------|--------|
^ ^ ^
| | |
sg->page ----+ | |
sg->offset --------------+ |
(sg->offset + sg->length) ----------+
As a result, the caller ends up overrunning the mapping into whatever
lies beyond, which usually goes badly:
[ 429.645492] DMAR: DRHD: handling fault status reg 2
[ 429.650847] DMAR: [DMA Write] Request device [02:00.4] fault addr f2682000 ...
Whilst this is a fairly rare occurrence, it can happen from the result
of intermediate scatterlist processing such as scatterwalk_ffwd() in the
crypto layer. Whilst that particular site could be fixed up, it still
seems worthwhile to bring intel-iommu in line with other DMA API
implementations in handling this robustly.
To that end, fix the intel_map_sg() path to line up the mapping
correctly (in units of MM pages rather than VT-d pages to match the
aligned_nrpages() calculation) regardless of the offset, and use
sg_phys() consistently for clarity.
Reported-by: Harsh Jain <Harsh@chelsio.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed by: Ashok Raj <ashok.raj@intel.com>
Tested by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index f9711aceef54..4efec2db4ee2 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2201,10 +2201,12 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, uint64_t tmp; if (!sg_res) { + unsigned int pgoff = 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) + pgoff; sg->dma_length = sg->length; - pteval = page_to_phys(sg_page(sg)) | prot; + pteval = (sg_phys(sg) - pgoff) | prot; phys_pfn = pteval >> VTD_PAGE_SHIFT; } @@ -3757,7 +3759,7 @@ static int intel_nontranslate_map_sg(struct device *hddev, for_each_sg(sglist, sg, nelems, i) { BUG_ON(!sg_page(sg)); - sg->dma_address = page_to_phys(sg_page(sg)) + sg->offset; + sg->dma_address = sg_phys(sg); sg->dma_length = sg->length; } return nelems; |