Hi Mitch, On 25/07/16 20:16, Mitchel Humpherys wrote: > 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. > > Signed-off-by: Mitchel Humpherys <[email protected]> > --- > > Notes: > v3..v4 > > - Reworked against the new dma attrs format > > v2..v3 > > - Renamed and redocumented dma_direction_to_prot. > - Dropped the stuff making all privileged mappings read-only. > > arch/arm64/mm/dma-mapping.c | 6 +++--- > drivers/iommu/dma-iommu.c | 16 +++++++++++----- > include/linux/dma-iommu.h | 3 ++- > 3 files changed, 16 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > index c4284c432ae8..1c6f85c56115 100644 > --- a/arch/arm64/mm/dma-mapping.c > +++ b/arch/arm64/mm/dma-mapping.c > @@ -556,7 +556,7 @@ 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; > > @@ -710,7 +710,7 @@ 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) && > @@ -768,7 +768,7 @@ 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 08a1e2f3690f..5e1e495b35f8 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -129,26 +129,32 @@ int iommu_dma_init_domain(struct iommu_domain *domain, > dma_addr_t base, u64 size > 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; + then drop the rest of the changes to the switch statement below. It's taken me an embarrassingly long time to work out why things were blowing up in __iommu_sync_single_for_device() all with a VA of phys_to_virt(0) ;) With that change, for the whole series: Reviewed-by: Robin Murphy <[email protected]> Tested-by: Robin Murphy <[email protected]> I guess at this point it may be worth waiting to repost based on -rc1. Be sure to CC patch 5 to Vinod as the current dmaengine maintainer, as it's his ack we'll need on that. Cheers, Robin. > switch (dir) { > case DMA_BIDIRECTIONAL: > - return prot | IOMMU_READ | IOMMU_WRITE; > + prot |= IOMMU_READ | IOMMU_WRITE; > case DMA_TO_DEVICE: > - return prot | IOMMU_READ; > + prot |= IOMMU_READ; > case DMA_FROM_DEVICE: > - return prot | IOMMU_WRITE; > + prot |= IOMMU_WRITE; > default: > return 0; > } > + if (attrs & DMA_ATTR_PRIVILEGED) > + prot |= IOMMU_PRIV; > + return prot; > } > > static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size, > diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h > index 81c5c8d167ad..b367613d49ba 100644 > --- a/include/linux/dma-iommu.h > +++ b/include/linux/dma-iommu.h > @@ -32,7 +32,8 @@ void iommu_put_dma_cookie(struct iommu_domain *domain); > int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 > size); > > /* 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 >
