iommu/vt-d: Detach domain before using a private one

When the default domain of a group doesn't work for a device,
the iommu driver will try to use a private domain. The domain
which was previously attached to the device must be detached.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Fixes: 942067f1 ("iommu/vt-d: Identify default domains replaced with private")
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lkml.org/lkml/2019/8/2/1379Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -3449,6 +3449,7 @@ static bool iommu_need_mapping(struct device *dev)
 				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);
 		}
 
@@ -4803,7 +4804,8 @@ static void dmar_remove_one_dev_info(struct device *dev)
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	info = dev->archdata.iommu;
-	__dmar_remove_one_dev_info(info);
+	if (info)
+		__dmar_remove_one_dev_info(info);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
@@ -5281,6 +5283,7 @@ static int intel_iommu_add_device(struct device *dev)
 		if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) {
 			ret = iommu_request_dm_for_dev(dev);
 			if (ret) {
+				dmar_remove_one_dev_info(dev);
 				dmar_domain->flags |= DOMAIN_FLAG_LOSE_CHILDREN;
 				domain_add_dev_info(si_domain, dev);
 				dev_info(dev,
@@ -5291,6 +5294,7 @@ static int intel_iommu_add_device(struct device *dev)
 		if (device_def_domain_type(dev) == IOMMU_DOMAIN_DMA) {
 			ret = iommu_request_dma_domain_for_dev(dev);
 			if (ret) {
+				dmar_remove_one_dev_info(dev);
 				dmar_domain->flags |= DOMAIN_FLAG_LOSE_CHILDREN;
 				if (!get_private_domain_for_dev(dev)) {
 					dev_warn(dev,