2019-05-20 07:33:31

by Christoph Hellwig

Subject: [PATCH 01/24] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable

DMA allocations that can't sleep may return non-remapped addresses, but
we do not properly handle them in the mmap and get_sgtable methods.
Resolve non-vmalloc addresses using virt_to_page to handle this corner
case.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Robin Murphy <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
---
arch/arm64/mm/dma-mapping.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 78c0a72f822c..674860e3e478 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -249,6 +249,11 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
return ret;

+ if (!is_vmalloc_addr(cpu_addr)) {
+ unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+ return __swiotlb_mmap_pfn(vma, pfn, size);
+ }
+
if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
/*
* DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
@@ -272,6 +277,11 @@ static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
struct vm_struct *area = find_vm_area(cpu_addr);

+ if (!is_vmalloc_addr(cpu_addr)) {
+ struct page *page = virt_to_page(cpu_addr);
+ return __swiotlb_get_sgtable_page(sgt, page, size);
+ }
+
if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
/*
* DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
--
2.20.1

2019-05-22 12:57:55

by Will Deacon

Subject: Re: [PATCH 01/24] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable

On Mon, May 20, 2019 at 09:29:25AM +0200, Christoph Hellwig wrote:
> DMA allocations that can't sleep may return non-remapped addresses, but
> we do not properly handle them in the mmap and get_sgtable methods.
> Resolve non-vmalloc addresses using virt_to_page to handle this corner
> case.
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> Reviewed-by: Robin Murphy <[email protected]>
> Acked-by: Catalin Marinas <[email protected]>
> ---
> arch/arm64/mm/dma-mapping.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)

I'll send this one to Linus this week as part of the arm64 fixes.

Will