[PATCH v5 02/10] iommu/vt-d: Use per-device dma_ops

[Lu Baolu]

Current Intel IOMMU driver sets the system level dma_ops hence
each dma API will go through the IOMMU driver even the devices
are using an identity mapped domain. This applies per-device
dma_ops in this driver and leave the system level dma_ops for
direct dma.

Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>\
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel-iommu.c | 43 ++++++-------------------------------
 1 file changed, 7 insertions(+), 36 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 8064af607d3b..11474bd2e348 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3419,43 +3419,10 @@ 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)
 {
-	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_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;
-			}
-			get_private_domain_for_dev(dev);
-		}
-
-		dev_info(dev, "32bit DMA uses non-identity mapping\n");
-	}
-
-	return true;
+	return !identity_mapping(dev);
 }
 
 static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
@@ -4706,8 +4673,6 @@ int __init intel_iommu_init(void)
 	}
 	up_write(&dmar_global_lock);
 
-	dma_ops = &intel_dma_ops;
-
 	init_iommu_pm_ops();
 
 	for_each_active_iommu(iommu, drhd) {
@@ -5280,6 +5245,8 @@ static int intel_iommu_add_device(struct device *dev)
 				dev_info(dev,
 					 "Device uses a private identity domain.\n");
 			}
+		} else {
+			set_dma_ops(dev, &intel_dma_ops);
 		}
 	} else {
 		if (device_def_domain_type(dev) == IOMMU_DOMAIN_DMA) {
@@ -5295,6 +5262,8 @@ static int intel_iommu_add_device(struct device *dev)
 				dev_info(dev,
 					 "Device uses a private dma domain.\n");
 			}
+
+			set_dma_ops(dev, &intel_dma_ops);
 		}
 	}
 
@@ -5313,6 +5282,8 @@ static void intel_iommu_remove_device(struct device *dev)
 	iommu_group_remove_device(dev);
 
 	iommu_device_unlink(&iommu->iommu, dev);
+
+	set_dma_ops(dev, NULL);
 }
 
 static void intel_iommu_get_resv_regions(struct device *device,
-- 
2.17.1