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dma-mapping fixes for Linux 6.9 

This has a set of swiotlb alignment fixes for sometimes very long
 standing bugs from Will.  We've been discussion them for a while and they
 should be solid now.
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Merge tag 'dma-mapping-6.9-2024-03-24' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:
 "This has a set of swiotlb alignment fixes for sometimes very long
  standing bugs from Will. We've been discussion them for a while and
  they should be solid now"

* tag 'dma-mapping-6.9-2024-03-24' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: Reinstate page-alignment for mappings >= PAGE_SIZE
  iommu/dma: Force swiotlb_max_mapping_size on an untrusted device
  swiotlb: Fix alignment checks when both allocation and DMA masks are present
  swiotlb: Honour dma_alloc_coherent() alignment in swiotlb_alloc()
  swiotlb: Enforce page alignment in swiotlb_alloc()
  swiotlb: Fix double-allocation of slots due to broken alignment handling
This commit is contained in:
Linus Torvalds 2024-03-24 10:45:31 -07:00
parent 70293240c5 14cebf689a
commit 864ad046c1
2 changed files with 43 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/iommu/dma-iommu.c
View File

@ -1711,6 +1711,14 @@ static size_t iommu_dma_opt_mapping_size(void)
return iova_rcache_range();
}
static size_t iommu_dma_max_mapping_size(struct device *dev)
{
if (dev_is_untrusted(dev))
return swiotlb_max_mapping_size(dev);
return SIZE_MAX;
}
static const struct dma_map_ops iommu_dma_ops = {
.flags = DMA_F_PCI_P2PDMA_SUPPORTED,
.alloc = iommu_dma_alloc,
@ -1733,6 +1741,7 @@ static const struct dma_map_ops iommu_dma_ops = {
.unmap_resource = iommu_dma_unmap_resource,
.get_merge_boundary = iommu_dma_get_merge_boundary,
.opt_mapping_size = iommu_dma_opt_mapping_size,
.max_mapping_size = iommu_dma_max_mapping_size,
};
/*

47
kernel/dma/swiotlb.c
View File

@ -1003,8 +1003,7 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool
dma_addr_t tbl_dma_addr =
phys_to_dma_unencrypted(dev, pool->start) & boundary_mask;
unsigned long max_slots = get_max_slots(boundary_mask);
unsigned int iotlb_align_mask =
dma_get_min_align_mask(dev) | alloc_align_mask;
unsigned int iotlb_align_mask = dma_get_min_align_mask(dev);
unsigned int nslots = nr_slots(alloc_size), stride;
unsigned int offset = swiotlb_align_offset(dev, orig_addr);
unsigned int index, slots_checked, count = 0, i;
@ -1016,18 +1015,29 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool
BUG_ON(area_index >= pool->nareas);
/*
* For allocations of PAGE_SIZE or larger only look for page aligned
* allocations.
* Historically, swiotlb allocations >= PAGE_SIZE were guaranteed to be
* page-aligned in the absence of any other alignment requirements.
* 'alloc_align_mask' was later introduced to specify the alignment
* explicitly, however this is passed as zero for streaming mappings
* and so we preserve the old behaviour there in case any drivers are
* relying on it.
*/
if (alloc_size >= PAGE_SIZE)
iotlb_align_mask |= ~PAGE_MASK;
iotlb_align_mask &= ~(IO_TLB_SIZE - 1);
if (!alloc_align_mask && !iotlb_align_mask && alloc_size >= PAGE_SIZE)
alloc_align_mask = PAGE_SIZE - 1;
/*
* Ensure that the allocation is at least slot-aligned and update
* 'iotlb_align_mask' to ignore bits that will be preserved when
* offsetting into the allocation.
*/
alloc_align_mask |= (IO_TLB_SIZE - 1);
iotlb_align_mask &= ~alloc_align_mask;
/*
* For mappings with an alignment requirement don't bother looping to
* unaligned slots once we found an aligned one.
*/
stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1;
stride = get_max_slots(max(alloc_align_mask, iotlb_align_mask));
spin_lock_irqsave(&area->lock, flags);
if (unlikely(nslots > pool->area_nslabs - area->used))
@ -1037,11 +1047,14 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool
index = area->index;
for (slots_checked = 0; slots_checked < pool->area_nslabs; ) {
slot_index = slot_base + index;
phys_addr_t tlb_addr;
if (orig_addr &&
(slot_addr(tbl_dma_addr, slot_index) &
iotlb_align_mask) != (orig_addr & iotlb_align_mask)) {
slot_index = slot_base + index;
tlb_addr = slot_addr(tbl_dma_addr, slot_index);
if ((tlb_addr & alloc_align_mask) ||
(orig_addr && (tlb_addr & iotlb_align_mask) !=
(orig_addr & iotlb_align_mask))) {
index = wrap_area_index(pool, index + 1);
slots_checked++;
continue;
@ -1677,16 +1690,24 @@ struct page *swiotlb_alloc(struct device *dev, size_t size)
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
phys_addr_t tlb_addr;
unsigned int align;
int index;
if (!mem)
return NULL;
index = swiotlb_find_slots(dev, 0, size, 0, &pool);
align = (1 << (get_order(size) + PAGE_SHIFT)) - 1;
index = swiotlb_find_slots(dev, 0, size, align, &pool);
if (index == -1)
return NULL;
tlb_addr = slot_addr(pool->start, index);
if (unlikely(!PAGE_ALIGNED(tlb_addr))) {
dev_WARN_ONCE(dev, 1, "Cannot allocate pages from non page-aligned swiotlb addr 0x%pa.\n",
&tlb_addr);
swiotlb_release_slots(dev, tlb_addr);
return NULL;
}
return pfn_to_page(PFN_DOWN(tlb_addr));
}