2020-06-22 20:27:00

by Eric Auger

Subject: [PATCH] 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(-)

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index e739a6eea6e7..a3151a9b0c08 100644
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -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;
--
2.20.1

2020-06-23 11:43:44

by Christoph Hellwig

Subject: Re: [PATCH] dma-remap: Align the size in dma_common_*_remap()

On Mon, Jun 22, 2020 at 10:23:20PM +0200, Eric Auger wrote:
> 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(-)
>
> diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
> index e739a6eea6e7..a3151a9b0c08 100644
> --- a/kernel/dma/remap.c
> +++ b/kernel/dma/remap.c
> @@ -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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