diff options
| author | Robin Murphy <robin.murphy@arm.com> | 2015-07-16 19:40:12 +0100 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2015-07-28 15:47:56 +0100 |
| commit | 8f6429c7cb59f28433253575cc8e3262eed63592 (patch) | |
| tree | b0ba92c894735701a01d289f92c42c221c6d3cf1 | |
| parent | 52721d9d3334c1cb1f76219a161084094ec634dc (diff) | |
iommu/iova: Avoid over-allocating when size-aligned
Currently, allocating a size-aligned IOVA region quietly adjusts the
actual allocation size in the process, returning a rounded-up
power-of-two-sized allocation. This results in mismatched behaviour in
the IOMMU driver if the original size was not a power of two, where the
original size is mapped, but the rounded-up IOVA size is unmapped.
Whilst some IOMMUs will happily unmap already-unmapped pages, others
consider this an error, so fix it by computing the necessary alignment
padding without altering the actual allocation size. Also clean up by
making pad_size unsigned, since its callers always pass unsigned values
and negative padding makes little sense here anyway.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 2 | ||||
| -rw-r--r-- | drivers/iommu/iova.c | 23 |
2 files changed, 8 insertions, 17 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a98a7b27aca1..92101597cede 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3233,6 +3233,8 @@ static struct iova *intel_alloc_iova(struct device *dev, /* Restrict dma_mask to the width that the iommu can handle */ dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw), dma_mask); + /* Ensure we reserve the whole size-aligned region */ + nrpages = __roundup_pow_of_two(nrpages); if (!dmar_forcedac && dma_mask > DMA_BIT_MASK(32)) { /* diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index b7c3d923f3e1..29f2efcf668e 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -120,19 +120,14 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) } } -/* Computes the padding size required, to make the - * the start address naturally aligned on its size +/* + * Computes the padding size required, to make the start address + * naturally aligned on the power-of-two order of its size */ -static int -iova_get_pad_size(int size, unsigned int limit_pfn) +static unsigned int +iova_get_pad_size(unsigned int size, unsigned int limit_pfn) { - unsigned int pad_size = 0; - unsigned int order = ilog2(size); - - if (order) - pad_size = (limit_pfn + 1) % (1 << order); - - return pad_size; + return (limit_pfn + 1 - size) & (__roundup_pow_of_two(size) - 1); } static int __alloc_and_insert_iova_range(struct iova_domain *iovad, @@ -265,12 +260,6 @@ alloc_iova(struct iova_domain *iovad, unsigned long size, if (!new_iova) return NULL; - /* If size aligned is set then round the size to - * to next power of two. - */ - if (size_aligned) - size = __roundup_pow_of_two(size); - ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn, new_iova, size_aligned); |