Current Intel IOMMU driver sets the system level dma_ops. This causes
each dma API to go through the IOMMU driver even the devices are using
identity mapped domains. This sets per-device dma_ops only if a device
is using a DMA domain. Otherwise, use the default system level dma_ops
for direct dma.

Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 82 ++++++++++++-------------------------
 1 file changed, 26 insertions(+), 56 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index af309e8fa6f5..29d3940847d3 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2720,17 +2720,6 @@ static int __init si_domain_init(int hw)
        return 0;
 }
 
-static int identity_mapping(struct device *dev)
-{
-       struct device_domain_info *info;
-
-       info = dev->archdata.iommu;
-       if (info)
-               return (info->domain == si_domain);
-
-       return 0;
-}
-
 static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 {
        struct dmar_domain *ndomain;
@@ -3315,18 +3304,6 @@ static unsigned long intel_alloc_iova(struct device *dev,
        return iova_pfn;
 }
 
-/* Check if the dev needs to go through non-identity map and unmap process.*/
-static bool iommu_need_mapping(struct device *dev)
-{
-       if (iommu_dummy(dev))
-               return false;
-
-       if (unlikely(attach_deferred(dev)))
-               do_deferred_attach(dev);
-
-       return !identity_mapping(dev);
-}
-
 static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
                                     size_t size, int dir, u64 dma_mask)
 {
@@ -3340,6 +3317,9 @@ static dma_addr_t __intel_map_single(struct device *dev, 
phys_addr_t paddr,
 
        BUG_ON(dir == DMA_NONE);
 
+       if (unlikely(attach_deferred(dev)))
+               do_deferred_attach(dev);
+
        domain = find_domain(dev);
        if (!domain)
                return DMA_MAPPING_ERROR;
@@ -3391,20 +3371,15 @@ 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);
+       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);
+       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)
@@ -3455,17 +3430,13 @@ 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
-               dma_direct_unmap_page(dev, dev_addr, size, dir, attrs);
+       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))
-               intel_unmap(dev, dev_addr, size);
+       intel_unmap(dev, dev_addr, size);
 }
 
 static void *intel_alloc_coherent(struct device *dev, size_t size,
@@ -3475,8 +3446,8 @@ static void *intel_alloc_coherent(struct device *dev, 
size_t size,
        struct page *page = NULL;
        int order;
 
-       if (!iommu_need_mapping(dev))
-               return dma_direct_alloc(dev, size, dma_handle, flags, attrs);
+       if (unlikely(attach_deferred(dev)))
+               do_deferred_attach(dev);
 
        size = PAGE_ALIGN(size);
        order = get_order(size);
@@ -3511,9 +3482,6 @@ 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))
-               return dma_direct_free(dev, size, vaddr, dma_handle, attrs);
-
        size = PAGE_ALIGN(size);
        order = get_order(size);
 
@@ -3531,9 +3499,6 @@ static void intel_unmap_sg(struct device *dev, struct 
scatterlist *sglist,
        struct scatterlist *sg;
        int i;
 
-       if (!iommu_need_mapping(dev))
-               return dma_direct_unmap_sg(dev, sglist, nelems, dir, attrs);
-
        for_each_sg(sglist, sg, nelems, i) {
                nrpages += aligned_nrpages(sg_dma_address(sg), sg_dma_len(sg));
        }
@@ -3557,8 +3522,9 @@ 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))
-               return dma_direct_map_sg(dev, sglist, nelems, dir, attrs);
+
+       if (unlikely(attach_deferred(dev)))
+               do_deferred_attach(dev);
 
        domain = find_domain(dev);
        if (!domain)
@@ -3605,8 +3571,6 @@ 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))
-               return dma_direct_get_required_mask(dev);
        return DMA_BIT_MASK(32);
 }
 
@@ -4888,8 +4852,6 @@ int __init intel_iommu_init(void)
        }
        up_write(&dmar_global_lock);
 
-       dma_ops = &intel_dma_ops;
-
        init_iommu_pm_ops();
 
        down_read(&dmar_global_lock);
@@ -5479,11 +5441,6 @@ static struct iommu_device 
*intel_iommu_probe_device(struct device *dev)
        if (translation_pre_enabled(iommu))
                dev->archdata.iommu = DEFER_DEVICE_DOMAIN_INFO;
 
-       if (device_needs_bounce(dev)) {
-               dev_info(dev, "Use Intel IOMMU bounce page dma_ops\n");
-               set_dma_ops(dev, &bounce_dma_ops);
-       }
-
        return &iommu->iommu;
 }
 
@@ -5498,7 +5455,19 @@ static void intel_iommu_release_device(struct device 
*dev)
 
        dmar_remove_one_dev_info(dev);
 
+       set_dma_ops(dev, NULL);
+}
+
+static void intel_iommu_probe_finalize(struct device *dev)
+{
+       struct iommu_domain *domain;
+
+       domain = iommu_get_domain_for_dev(dev);
        if (device_needs_bounce(dev))
+               set_dma_ops(dev, &bounce_dma_ops);
+       else if (domain && domain->type == IOMMU_DOMAIN_DMA)
+               set_dma_ops(dev, &intel_dma_ops);
+       else
                set_dma_ops(dev, NULL);
 }
 
@@ -5830,6 +5799,7 @@ const struct iommu_ops intel_iommu_ops = {
        .unmap                  = intel_iommu_unmap,
        .iova_to_phys           = intel_iommu_iova_to_phys,
        .probe_device           = intel_iommu_probe_device,
+       .probe_finalize         = intel_iommu_probe_finalize,
        .release_device         = intel_iommu_release_device,
        .get_resv_regions       = intel_iommu_get_resv_regions,
        .put_resv_regions       = generic_iommu_put_resv_regions,
-- 
2.17.1

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