Messages in this thread Patch in this message | | | Date | Tue, 5 Apr 2011 17:39:19 -0700 | From | Chris Wright <> | Subject | [PATCH 3/4 v3] intel-iommu: don't cache iova above 32bit caching boundary |
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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: David Woodhouse <dwmw2@infradead.org> 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> ---
v3: rb_next() can return NULL, found when testing on my hw
David, Mike Travis will collect and resumbit full series when he's back.
drivers/pci/iova.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/iova.c b/drivers/pci/iova.c index 7914951..10f995a 100644 --- a/drivers/pci/iova.c +++ b/drivers/pci/iova.c @@ -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 -- 1.7.4
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