[PATCH v3 6/9] iommu/vt-d: Make intel_iommu_set_dev_pasid() to handle domain replacement

[Yi Liu <yi.l.liu@xxxxxxxxx>]

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

Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/intel/iommu.c | 97 ++++++++++++++++++++++++-------------
 1 file changed, 64 insertions(+), 33 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8d92a221d020..302260898c36 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4250,8 +4250,8 @@ 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_remove_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;
@@ -4259,11 +4259,6 @@ 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) {
-		intel_pasid_tear_down_entry(iommu, dev, pasid, 0);
-		return;
-	}
-
 	dmar_domain = to_dmar_domain(domain);
 	spin_lock_irqsave(&dmar_domain->lock, flags);
 	list_for_each_entry(curr, &dmar_domain->dev_pasids, link_domain) {
@@ -4280,13 +4275,27 @@ 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);
+}
+
+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,
 				    INTEL_PASID_TEARDOWN_DRAIN_PRQ);
+
+	/* Identity domain has no meta data for pasid. */
+	if (domain->type == IOMMU_DOMAIN_IDENTITY)
+		return;
+
+	domain_remove_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_add_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);
@@ -4295,22 +4304,13 @@ 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 = domain_attach_device_sanitize(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)
@@ -4320,6 +4320,43 @@ 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_add_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);
@@ -4327,24 +4364,18 @@ 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_remove_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);
+	if (old)
+		domain_remove_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_remove_dev_pasid:
+	domain_remove_dev_pasid(domain, dev, pasid);
 	return ret;
 }
 
-- 
2.34.1