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FROMGIT: iommu/dma: Factor out a iommu_dma_map_swiotlb helper

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Split the iommu logic from iommu_dma_map_page into a separate helper.
This not only keeps the code neatly separated, but will also allow for
reuse in another caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
(cherry picked from commit ed18a46262be4397cdc24382fb331c68846fef6e
 https://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux.git)
Bug: 416098329
[Daniel: Adopted to commit ed5035757c ("BACKPORT: FROMLIST: PCI: Rename
pci_dev->untrusted to pci_dev->requires_dma_protection")]
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Change-Id: I0ece9ce844ebcbab5ee6c6c6b0e99dea6255a77b
This commit is contained in:
Christoph Hellwig
2025-05-05 10:01:43 +03:00
committed by Carlos Llamas
parent 0f2253b2b1
commit 59a15e3bf1
1 changed files with 41 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

73
drivers/iommu/dma-iommu.c
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@@ -1171,6 +1171,43 @@ void iommu_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
arch_sync_dma_for_device(sg_phys(sg), sg->length, dir);
}
static phys_addr_t iommu_dma_map_swiotlb(struct device *dev, phys_addr_t phys,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iova_domain *iovad = &domain->iova_cookie->iovad;
if (!is_swiotlb_active(dev)) {
dev_warn_once(dev, "DMA bounce buffers are inactive, unable to map unaligned transaction.\n");
return (phys_addr_t)DMA_MAPPING_ERROR;
}
trace_swiotlb_bounced(dev, phys, size);
phys = swiotlb_tbl_map_single(dev, phys, size, iova_mask(iovad), dir,
attrs);
/*
* Zero the pre- and post-padding to prevent exposing kernel data to devices
* requiring DMA protection.
* swiotlb_tbl_map_single() has initialized the bounce buffer proper to
* the contents of the original memory buffer.
*/
if (phys != (phys_addr_t)DMA_MAPPING_ERROR && dev_requires_dma_protection(dev)) {
size_t start, virt = (size_t)phys_to_virt(phys);
/* Pre-padding */
start = iova_align_down(iovad, virt);
memset((void *)start, 0, virt - start);
/* Post-padding */
start = virt + size;
memset((void *)start, 0, iova_align(iovad, start) - start);
}
return phys;
}
dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
@@ -1184,42 +1221,14 @@ dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
dma_addr_t iova, dma_mask = dma_get_mask(dev);
/*
* If both the physical buffer start address and size are
* page aligned, we don't need to use a bounce page.
* If both the physical buffer start address and size are page aligned,
* we don't need to use a bounce page.
*/
if (dev_use_swiotlb(dev, size, dir) &&
iova_offset(iovad, phys | size)) {
if (!is_swiotlb_active(dev)) {
dev_warn_once(dev, "DMA bounce buffers are inactive, unable to map unaligned transaction.\n");
phys = iommu_dma_map_swiotlb(dev, phys, size, dir, attrs);
if (phys == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
}
trace_swiotlb_bounced(dev, phys, size);
phys = swiotlb_tbl_map_single(dev, phys, size,
iova_mask(iovad), dir, attrs);
if (phys == DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
/*
* Zero the pre- and post-padding to prevent exposing kernel data to devices
* requiring DMA protection.
* swiotlb_tbl_map_single() has initialized the bounce buffer
* proper to the contents of the original memory buffer.
*/
if (dev_requires_dma_protection(dev)) {
size_t start, virt = (size_t)phys_to_virt(phys);
/* Pre-padding */
start = iova_align_down(iovad, virt);
memset((void *)start, 0, virt - start);
/* Post-padding */
start = virt + size;
memset((void *)start, 0,
iova_align(iovad, start) - start);
}
}
if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))