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authorJiang Liu <jiang.liu@linux.intel.com>2014-11-26 09:42:10 +0800
committerJoerg Roedel <jroedel@suse.de>2014-12-02 13:03:09 +0100
commitcc4f14aa170d895c9a43bdb56f62070c8a6da908 (patch)
treeaa8e7d2d6634e0713a9773a77659759f16d967cd /drivers/iommu
parent864b94adfcba752aa902ee34497bbe58b97aa8d3 (diff)
downloadlinux-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.c8
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;
}