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| author | Jiang Liu <jiang.liu@linux.intel.com> | 2014-11-26 09:42:10 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2014-12-02 13:03:09 +0100 |
| commit | cc4f14aa170d895c9a43bdb56f62070c8a6da908 (patch) | |
| tree | aa8e7d2d6634e0713a9773a77659759f16d967cd /drivers/iommu | |
| parent | 864b94adfcba752aa902ee34497bbe58b97aa8d3 (diff) | |
| download | linux-cc4f14aa170d895c9a43bdb56f62070c8a6da908.tar.bz2 | |
iommu/vt-d: Fix an off-by-one bug in __domain_mapping()
There's an off-by-one bug in function __domain_mapping(), which may
trigger the BUG_ON(nr_pages < lvl_pages) when
(nr_pages + 1) & superpage_mask == 0
The issue was introduced by commit 9051aa0268dc "intel-iommu: Combine
domain_pfn_mapping() and domain_sg_mapping()", which sets sg_res to
"nr_pages + 1" to avoid some of the 'sg_res==0' code paths.
It's safe to remove extra "+1" because sg_res is only used to calculate
page size now.
Reported-And-Tested-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: <stable@vger.kernel.org> # >= 3.0
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 99bf651234a6..fe6830af6cfa 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1986,7 +1986,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, { struct dma_pte *first_pte = NULL, *pte = NULL; phys_addr_t uninitialized_var(pteval); - unsigned long sg_res; + unsigned long sg_res = 0; unsigned int largepage_lvl = 0; unsigned long lvl_pages = 0; @@ -1997,10 +1997,8 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, prot &= DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP; - if (sg) - sg_res = 0; - else { - sg_res = nr_pages + 1; + if (!sg) { + sg_res = nr_pages; pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | prot; } |