diff options
| author | Jiang Liu <jiang.liu@linux.intel.com> | 2014-11-26 09:42:10 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-16 06:59:31 -0800 |
| commit | 4ce9fbccfb9ee64bec6ac125150e2beac5f0c42f (patch) | |
| tree | ef1d81a1d2d7e332eac061448167dfb7f36aa41e | |
| parent | e69001acba6725963d0bc5476ec380f56bd65932 (diff) | |
iommu/vt-d: Fix an off-by-one bug in __domain_mapping()
commit cc4f14aa170d895c9a43bdb56f62070c8a6da908 upstream.
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>
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 40f6b47c28f6..8855ecbc36be 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1768,7 +1768,7 @@ 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); int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT; - unsigned long sg_res; + unsigned long sg_res = 0; unsigned int largepage_lvl = 0; unsigned long lvl_pages = 0; @@ -1779,10 +1779,8 @@ 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; } |