On 12/12/16 18:38, Sricharan R wrote:
> From: Mitchel Humpherys <mitch...@codeaurora.org>
> 
> The newly added DMA_ATTR_PRIVILEGED is useful for creating mappings that
> are only accessible to privileged DMA engines.  Implement it in
> dma-iommu.c so that the ARM64 DMA IOMMU mapper can make use of it.
> 
> Reviewed-by: Robin Murphy <robin.mur...@arm.com>
> Tested-by: Robin Murphy <robin.mur...@arm.com>
> Acked-by: Will Deacon <will.dea...@arm.com>
> Signed-off-by: Mitchel Humpherys <mitch...@codeaurora.org>
> ---
>  arch/arm64/mm/dma-mapping.c |  6 +++---
>  drivers/iommu/dma-iommu.c   | 10 ++++++++--
>  include/linux/dma-iommu.h   |  3 ++-
>  3 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 401f79a..ae76ead 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -557,7 +557,7 @@ static void *__iommu_alloc_attrs(struct device *dev, 
> size_t size,
>                                unsigned long attrs)
>  {
>       bool coherent = is_device_dma_coherent(dev);
> -     int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent);
> +     int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
>       size_t iosize = size;
>       void *addr;
>  
> @@ -711,7 +711,7 @@ static dma_addr_t __iommu_map_page(struct device *dev, 
> struct page *page,
>                                  unsigned long attrs)
>  {
>       bool coherent = is_device_dma_coherent(dev);
> -     int prot = dma_direction_to_prot(dir, coherent);
> +     int prot = dma_info_to_prot(dir, coherent, attrs);
>       dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
>  
>       if (!iommu_dma_mapping_error(dev, dev_addr) &&
> @@ -769,7 +769,7 @@ static int __iommu_map_sg_attrs(struct device *dev, 
> struct scatterlist *sgl,
>               __iommu_sync_sg_for_device(dev, sgl, nelems, dir);
>  
>       return iommu_dma_map_sg(dev, sgl, nelems,
> -                     dma_direction_to_prot(dir, coherent));
> +                             dma_info_to_prot(dir, coherent, attrs));
>  }
>  
>  static void __iommu_unmap_sg_attrs(struct device *dev,
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index d2a7a46..756d5e0 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -182,16 +182,22 @@ int iommu_dma_init_domain(struct iommu_domain *domain, 
> dma_addr_t base,
>  EXPORT_SYMBOL(iommu_dma_init_domain);
>  
>  /**
> - * dma_direction_to_prot - Translate DMA API directions to IOMMU API page 
> flags
> + * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU 
> API
> + *                    page flags.
>   * @dir: Direction of DMA transfer
>   * @coherent: Is the DMA master cache-coherent?
> + * @attrs: DMA attributes for the mapping
>   *
>   * Return: corresponding IOMMU API page protection flags
>   */
> -int dma_direction_to_prot(enum dma_data_direction dir, bool coherent)
> +int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
> +                  unsigned long attrs)
>  {
>       int prot = coherent ? IOMMU_CACHE : 0;
>  
> +     if (attrs & DMA_ATTR_PRIVILEGED)
> +             prot |= IOMMU_PRIV;
> +
>       switch (dir) {
>       case DMA_BIDIRECTIONAL:
>               return prot | IOMMU_READ | IOMMU_WRITE;

...and applying against -next now also needs this hunk:

@@ -639,7 +639,7 @@ dma_addr_t iommu_dma_map_resource(struct device
*dev, phys_addr_t phys,
                size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
        return __iommu_dma_map(dev, phys, size,
-                       dma_direction_to_prot(dir, false) | IOMMU_MMIO);
+                       dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO);
 }

 void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,

With those two issues fixed up, I've given the series (applied to
next-20161213) a spin on a SMMUv3/PL330 fast model and it still checks out.

Robin.

> diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
> index 32c5890..a203181 100644
> --- a/include/linux/dma-iommu.h
> +++ b/include/linux/dma-iommu.h
> @@ -34,7 +34,8 @@ int iommu_dma_init_domain(struct iommu_domain *domain, 
> dma_addr_t base,
>               u64 size, struct device *dev);
>  
>  /* General helpers for DMA-API <-> IOMMU-API interaction */
> -int dma_direction_to_prot(enum dma_data_direction dir, bool coherent);
> +int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
> +                  unsigned long attrs);
>  
>  /*
>   * These implement the bulk of the relevant DMA mapping callbacks, but 
> require
> 

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