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    SubjectRe: [PATCH V7 5/8] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED
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    On 13/12/16 14:38, Sricharan wrote:
    > Hi Robin,
    >
    >> -----Original Message-----
    >> From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@lists.infradead.org] On Behalf Of Robin Murphy
    >> Sent: Tuesday, December 13, 2016 7:33 PM
    >> To: Sricharan R <sricharan@codeaurora.org>; jcrouse@codeaurora.org; pdaly@codeaurora.org; jgebben@codeaurora.org;
    >> joro@8bytes.org; linux-kernel@vger.kernel.org; pratikp@codeaurora.org; iommu@lists.linux-foundation.org; tzeng@codeaurora.org;
    >> linux-arm-kernel@lists.infradead.org; will.deacon@arm.com; mitchelh@codeaurora.org; vinod.koul@intel.com
    >> Cc: dan.j.williams@intel.com
    >> Subject: Re: [PATCH V7 5/8] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED
    >>
    >> On 12/12/16 18:38, Sricharan R wrote:
    >>> From: Mitchel Humpherys <mitchelh@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.murphy@arm.com>
    >>> Tested-by: Robin Murphy <robin.murphy@arm.com>
    >>> Acked-by: Will Deacon <will.deacon@arm.com>
    >>> Signed-off-by: Mitchel Humpherys <mitchelh@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.
    >>
    >
    > oops, sorry that i missed this in rebase. I can repost now with this fixed,
    > 'checks out' you mean something is not working correct ?

    No, I mean it _is_ still correct - I guess that's more of an idiom than
    I thought :)

    Robin.

    >
    > Regards,
    > Sricharan
    >

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