In the intel iommu driver devices which only support 32bit DMA can't be direct mapped. The implementation of this is weird. Currently we assign it a direct mapped domain and then remove the domain later and replace it with a domain of type IOMMU_DOMAIN_IDENTITY. We should just assign it a domain of type IOMMU_DOMAIN_IDENTITY from the begging rather than needlessly swapping domains.
Signed-off-by: Tom Murphy murphyt7@tcd.ie --- drivers/iommu/intel-iommu.c | 88 +++++++++++++------------------------ 1 file changed, 31 insertions(+), 57 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 0c8d81f56a30..c1ea66467918 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3462,46 +3462,9 @@ static struct dmar_domain *get_private_domain_for_dev(struct device *dev) }
/* Check if the dev needs to go through non-identity map and unmap process.*/ -static bool iommu_need_mapping(struct device *dev) +static bool iommu_no_mapping(struct device *dev) { - int ret; - - if (iommu_dummy(dev)) - return false; - - ret = identity_mapping(dev); - if (ret) { - u64 dma_mask = *dev->dma_mask; - - if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask) - dma_mask = dev->coherent_dma_mask; - - if (dma_mask >= dma_direct_get_required_mask(dev)) - return false; - - /* - * 32 bit DMA is removed from si_domain and fall back to - * non-identity mapping. - */ - dmar_remove_one_dev_info(dev); - ret = iommu_request_dma_domain_for_dev(dev); - if (ret) { - struct iommu_domain *domain; - struct dmar_domain *dmar_domain; - - domain = iommu_get_domain_for_dev(dev); - if (domain) { - dmar_domain = to_dmar_domain(domain); - dmar_domain->flags |= DOMAIN_FLAG_LOSE_CHILDREN; - } - dmar_remove_one_dev_info(dev); - get_private_domain_for_dev(dev); - } - - dev_info(dev, "32bit DMA uses non-identity mapping\n"); - } - - return true; + return iommu_dummy(dev) || identity_mapping(dev); }
static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr, @@ -3568,20 +3531,22 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page, enum dma_data_direction dir, unsigned long attrs) { - if (iommu_need_mapping(dev)) - return __intel_map_single(dev, page_to_phys(page) + offset, - size, dir, *dev->dma_mask); - return dma_direct_map_page(dev, page, offset, size, dir, attrs); + if (iommu_no_mapping(dev)) + return dma_direct_map_page(dev, page, offset, size, dir, attrs); + + return __intel_map_single(dev, page_to_phys(page) + offset, size, dir, + *dev->dma_mask); }
static dma_addr_t intel_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { - if (iommu_need_mapping(dev)) - return __intel_map_single(dev, phys_addr, size, dir, - *dev->dma_mask); - return dma_direct_map_resource(dev, phys_addr, size, dir, attrs); + if (iommu_no_mapping(dev)) + return dma_direct_map_resource(dev, phys_addr, size, dir, + attrs); + + return __intel_map_single(dev, phys_addr, size, dir, *dev->dma_mask); }
static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size) @@ -3632,16 +3597,16 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { - if (iommu_need_mapping(dev)) - intel_unmap(dev, dev_addr, size); - else + if (iommu_no_mapping(dev)) dma_direct_unmap_page(dev, dev_addr, size, dir, attrs); + else + intel_unmap(dev, dev_addr, size); }
static void intel_unmap_resource(struct device *dev, dma_addr_t dev_addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { - if (iommu_need_mapping(dev)) + if (!iommu_no_mapping(dev)) intel_unmap(dev, dev_addr, size); }
@@ -3652,7 +3617,7 @@ static void *intel_alloc_coherent(struct device *dev, size_t size, struct page *page = NULL; int order;
- if (!iommu_need_mapping(dev)) + if (iommu_no_mapping(dev)) return dma_direct_alloc(dev, size, dma_handle, flags, attrs);
size = PAGE_ALIGN(size); @@ -3688,7 +3653,7 @@ static void intel_free_coherent(struct device *dev, size_t size, void *vaddr, int order; struct page *page = virt_to_page(vaddr);
- if (!iommu_need_mapping(dev)) + if (iommu_no_mapping(dev)) return dma_direct_free(dev, size, vaddr, dma_handle, attrs);
size = PAGE_ALIGN(size); @@ -3708,7 +3673,7 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist, struct scatterlist *sg; int i;
- if (!iommu_need_mapping(dev)) + if (iommu_no_mapping(dev)) return dma_direct_unmap_sg(dev, sglist, nelems, dir, attrs);
for_each_sg(sglist, sg, nelems, i) { @@ -3734,7 +3699,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele struct intel_iommu *iommu;
BUG_ON(dir == DMA_NONE); - if (!iommu_need_mapping(dev)) + if (iommu_no_mapping(dev)) return dma_direct_map_sg(dev, sglist, nelems, dir, attrs);
domain = deferred_attach_domain(dev); @@ -3782,7 +3747,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
static u64 intel_get_required_mask(struct device *dev) { - if (!iommu_need_mapping(dev)) + if (iommu_no_mapping(dev)) return dma_direct_get_required_mask(dev); return DMA_BIT_MASK(32); } @@ -5618,9 +5583,13 @@ static int intel_iommu_add_device(struct device *dev) struct iommu_domain *domain; struct intel_iommu *iommu; struct iommu_group *group; + u64 dma_mask = *dev->dma_mask; u8 bus, devfn; int ret;
+ if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask) + dma_mask = dev->coherent_dma_mask; + iommu = device_to_iommu(dev, &bus, &devfn); if (!iommu) return -ENODEV; @@ -5640,7 +5609,12 @@ static int intel_iommu_add_device(struct device *dev) domain = iommu_get_domain_for_dev(dev); dmar_domain = to_dmar_domain(domain); if (domain->type == IOMMU_DOMAIN_DMA) { - if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) { + /* + * We check dma_mask >= dma_get_required_mask(dev) because + * 32 bit DMA falls back to non-identity mapping. + */ + if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY && + dma_mask >= dma_get_required_mask(dev)) { ret = iommu_request_dm_for_dev(dev); if (ret) { dmar_remove_one_dev_info(dev);