dma-remap: Align the size in dma_common_*_remap()

PATCH Applied Eric Auger 2 participants 2 messages Jun 22, 2020 – Jun 23, 2020 DMA mapping helpers

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Eric Auger

author

2020-06-22 20:23 UTC #0 lore raw

PATCH 1/1 dma-remap: Align the size in dma_common_*_remap()

Running a guest with a virtio-iommu protecting virtio devices is broken since commit 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it"). Before the conversion, the size was page aligned in __get_vm_area_node(). Doing so fixes the regression.

Fixes 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it")

Signed-off-by Eric Auger <[email protected]>

---
 kernel/dma/remap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

kernel/dma/remap.c +2 -2

index e739a6eea6e7..a3151a9b0c08 100644
@@ -24,7 +24,7 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 {
 	void *vaddr;
 
-	vaddr = vmap(pages, size >> PAGE_SHIFT, VM_DMA_COHERENT, prot);
+	vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT, VM_DMA_COHERENT, prot);
 	if (vaddr)
 		find_vm_area(vaddr)->pages = pages;
 	return vaddr;

@@ -37,7 +37,7 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 void *dma_common_contiguous_remap(struct page *page, size_t size,
 			pgprot_t prot, const void *caller)
 {
-	int count = size >> PAGE_SHIFT;
+	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct page **pages;
 	void *vaddr;
 	int i;

Signature · 1 line

2.20.1

Christoph Hellwig

2020-06-23 11:40 UTC #1 lore raw

Quoted 17 lines · Eric Auger

Running a guest with a virtio-iommu protecting virtio devices is broken since commit 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it"). Before the conversion, the size was page aligned in __get_vm_area_node(). Doing so fixes the regression.
Fixes 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it")
Signed-off-by Eric Auger <[email protected]>
---
 kernel/dma/remap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
kernel/dma/remap.c +0 -0
index e739a6eea6e7..a3151a9b0c08 100644

kernel/dma/remap.c void *dma_common_pages_remap(struct page **pages, size_t size, · line 27

Quoted 5 lines

kernel/dma/remap.c +1 -1

@@ -24,7 +24,7 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 {
 	void *vaddr;
 
-	vaddr = vmap(pages, size >> PAGE_SHIFT, VM_DMA_COHERENT, prot);
+	vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT, VM_DMA_COHERENT, prot);

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