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intel-iommu: Dont cache iova above 32bit 

Mike Travis and Mike Habeck reported an issue where iova allocation
would return a range that was larger than a device's dma mask.

https://lkml.org/lkml/2011/3/29/423

The dmar initialization code will reserve all PCI MMIO regions and copy
those reservations into a domain specific iova tree.  It is possible for
one of those regions to be above the dma mask of a device.  It is typical
to allocate iovas with a 32bit mask (despite device's dma mask possibly
being larger) and cache the result until it exhausts the lower 32bit
address space.  Freeing the iova range that is >= the last iova in the
lower 32bit range when there is still an iova above the 32bit range will
corrupt the cached iova by pointing it to a region that is above 32bit.
If that region is also larger than the device's dma mask, a subsequent
allocation will return an unusable iova and cause dma failure.

Simply don't cache an iova that is above the 32bit caching boundary.

Reported-by: Mike Travis <travis@sgi.com>
Reported-by: Mike Habeck <habeck@sgi.com>
Cc: stable@kernel.org
Acked-by: Mike Travis <travis@sgi.com>
Tested-by: Mike Habeck <habeck@sgi.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Chris Wright 2011-05-28 13:15:04 -05:00 committed by David Woodhouse
parent cb452a4040
commit 1c9fc3d11b
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/pci/iova.c
View File

@ -63,8 +63,16 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
curr = iovad->cached32_node;
cached_iova = container_of(curr, struct iova, node);
if (free->pfn_lo >= cached_iova->pfn_lo)
iovad->cached32_node = rb_next(&free->node);
if (free->pfn_lo >= cached_iova->pfn_lo) {
struct rb_node *node = rb_next(&free->node);
struct iova *iova = container_of(node, struct iova, node);
/* only cache if it's below 32bit pfn */
if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
iovad->cached32_node = node;
else
iovad->cached32_node = NULL;
}
}
/* Computes the padding size required, to make the