[PATCH 4/6] iommu/vt-d: Make intel_iommu_set_dev_pasid() to handle domain replacement

[Yi Liu <yi.l.liu@intel.com>]

set_dev_pasid op is going to support domain replacement and keep the old
hardware config if it fails. Make the Intel iommu driver be prepared for
it.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/iommu/intel/debugfs.c |  2 +
 drivers/iommu/intel/iommu.c   | 94 +++++++++++++++++++++++------------
 2 files changed, 64 insertions(+), 32 deletions(-)

diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c
index affbf4a1558d..8deb6bc262c5 100644
--- a/drivers/iommu/intel/debugfs.c
+++ b/drivers/iommu/intel/debugfs.c
@@ -806,5 +806,7 @@ void intel_iommu_debugfs_create_dev_pasid(struct dev_pasid_info *dev_pasid)
 /* Remove the device pasid debugfs directory. */
 void intel_iommu_debugfs_remove_dev_pasid(struct dev_pasid_info *dev_pasid)
 {
+	if (!dev_pasid->debugfs_dentry)
+		return;
 	debugfs_remove_recursive(dev_pasid->debugfs_dentry);
 }
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index dd3de95c7122..8ef6c06f7e73 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4031,8 +4031,8 @@ static int intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
 	return 0;
 }
 
-static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
-					 struct iommu_domain *domain)
+static void domain_undo_dev_pasid(struct iommu_domain *domain,
+				  struct device *dev, ioasid_t pasid)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct dev_pasid_info *curr, *dev_pasid = NULL;
@@ -4040,9 +4040,6 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
 	struct dmar_domain *dmar_domain;
 	unsigned long flags;
 
-	if (domain->type == IOMMU_DOMAIN_IDENTITY)
-		goto out_tear_down;
-
 	dmar_domain = to_dmar_domain(domain);
 	spin_lock_irqsave(&dmar_domain->lock, flags);
 	list_for_each_entry(curr, &dmar_domain->dev_pasids, link_domain) {
@@ -4059,13 +4056,23 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
 	domain_detach_iommu(dmar_domain, iommu);
 	intel_iommu_debugfs_remove_dev_pasid(dev_pasid);
 	kfree(dev_pasid);
-out_tear_down:
+}
+
+static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
+					 struct iommu_domain *domain)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
+
 	intel_pasid_tear_down_entry(iommu, dev, pasid, false, true);
+	if (domain->type == IOMMU_DOMAIN_IDENTITY)
+		return;
+	domain_undo_dev_pasid(domain, dev, pasid);
 }
 
-static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
-				     struct device *dev, ioasid_t pasid,
-				     struct iommu_domain *old)
+static struct dev_pasid_info *
+domain_prepare_dev_pasid(struct iommu_domain *domain,
+			 struct device *dev, ioasid_t pasid)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
@@ -4074,22 +4081,13 @@ static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
 	unsigned long flags;
 	int ret;
 
-	if (!pasid_supported(iommu) || dev_is_real_dma_subdevice(dev))
-		return -EOPNOTSUPP;
-
-	if (domain->dirty_ops)
-		return -EINVAL;
-
-	if (context_copied(iommu, info->bus, info->devfn))
-		return -EBUSY;
-
 	ret = prepare_domain_attach_device(domain, dev);
 	if (ret)
-		return ret;
+		return ERR_PTR(ret);
 
 	dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
 	if (!dev_pasid)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	ret = domain_attach_iommu(dmar_domain, iommu);
 	if (ret)
@@ -4099,6 +4097,43 @@ static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
 	if (ret)
 		goto out_detach_iommu;
 
+	dev_pasid->dev = dev;
+	dev_pasid->pasid = pasid;
+	spin_lock_irqsave(&dmar_domain->lock, flags);
+	list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
+	spin_unlock_irqrestore(&dmar_domain->lock, flags);
+
+	return dev_pasid;
+out_detach_iommu:
+	domain_detach_iommu(dmar_domain, iommu);
+out_free:
+	kfree(dev_pasid);
+	return ERR_PTR(ret);
+}
+
+static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
+				     struct device *dev, ioasid_t pasid,
+				     struct iommu_domain *old)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+	struct intel_iommu *iommu = info->iommu;
+	struct dev_pasid_info *dev_pasid;
+	int ret;
+
+	if (!pasid_supported(iommu) || dev_is_real_dma_subdevice(dev))
+		return -EOPNOTSUPP;
+
+	if (domain->dirty_ops)
+		return -EINVAL;
+
+	if (context_copied(iommu, info->bus, info->devfn))
+		return -EBUSY;
+
+	dev_pasid = domain_prepare_dev_pasid(domain, dev, pasid);
+	if (IS_ERR(dev_pasid))
+		return PTR_ERR(dev_pasid);
+
 	if (dmar_domain->use_first_level)
 		ret = domain_setup_first_level(iommu, dmar_domain,
 					       dev, pasid);
@@ -4106,24 +4141,19 @@ static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
 		ret = intel_pasid_setup_second_level(iommu, dmar_domain,
 						     dev, pasid);
 	if (ret)
-		goto out_unassign_tag;
+		goto out_undo_dev_pasid;
 
-	dev_pasid->dev = dev;
-	dev_pasid->pasid = pasid;
-	spin_lock_irqsave(&dmar_domain->lock, flags);
-	list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
-	spin_unlock_irqrestore(&dmar_domain->lock, flags);
+	/* Undo the association between the old domain and pasid of a device */
+	if (old)
+		domain_undo_dev_pasid(old, dev, pasid);
 
 	if (domain->type & __IOMMU_DOMAIN_PAGING)
 		intel_iommu_debugfs_create_dev_pasid(dev_pasid);
 
 	return 0;
-out_unassign_tag:
-	cache_tag_unassign_domain(dmar_domain, dev, pasid);
-out_detach_iommu:
-	domain_detach_iommu(dmar_domain, iommu);
-out_free:
-	kfree(dev_pasid);
+
+out_undo_dev_pasid:
+	domain_undo_dev_pasid(domain, dev, pasid);
 	return ret;
 }
 
-- 
2.34.1