[PATCH v3 12/18] iommu/vt-d: Handle reattach of the restored domain

[Samiullah Khawaja]

Reattach the restored domain to the preserved device using restored
domain ID. While reattaching do not setup the context and PASID entries
as those are preserved during liveupdate.

Signed-off-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>
---
 drivers/iommu/intel/iommu.c      |  46 ++++++++++---
 drivers/iommu/intel/iommu.h      |  17 +++++
 drivers/iommu/intel/liveupdate.c | 111 +++++++++++++++++++++++++++++++
 3 files changed, 163 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cd40e274482b..91b67ccba011 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1311,10 +1311,16 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct intel_iommu *iommu = info->iommu;
+	struct iommu_device_ser *device_ser;
 	unsigned long flags;
 	int ret;
 
-	ret = domain_attach_iommu(domain, iommu);
+	device_ser = dev_iommu_restored_state(dev);
+	if (!device_ser)
+		ret = domain_attach_iommu(domain, iommu);
+	else
+		ret = intel_iommu_domain_reattach_iommu(domain,
+							iommu, device_ser);
 	if (ret)
 		return ret;
 
@@ -1327,16 +1333,20 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
 	if (dev_is_real_dma_subdevice(dev))
 		return 0;
 
-	if (!sm_supported(iommu))
-		ret = domain_context_mapping(domain, dev);
-	else if (intel_domain_is_fs_paging(domain))
-		ret = domain_setup_first_level(iommu, domain, dev,
-					       IOMMU_NO_PASID, NULL);
-	else if (intel_domain_is_ss_paging(domain))
-		ret = domain_setup_second_level(iommu, domain, dev,
-						IOMMU_NO_PASID, NULL);
-	else if (WARN_ON(true))
-		ret = -EINVAL;
+	if (!device_ser) {
+		if (!sm_supported(iommu))
+			ret = domain_context_mapping(domain, dev);
+		else if (intel_domain_is_fs_paging(domain))
+			ret = domain_setup_first_level(iommu, domain, dev,
+						       IOMMU_NO_PASID, NULL);
+		else if (intel_domain_is_ss_paging(domain))
+			ret = domain_setup_second_level(iommu, domain, dev,
+							IOMMU_NO_PASID, NULL);
+		else if (WARN_ON(true))
+			ret = -EINVAL;
+	} else if (!sm_supported(iommu)) {
+		iommu_enable_pci_ats(info);
+	}
 
 	if (ret)
 		goto out_block_translation;
@@ -3145,6 +3155,19 @@ int paging_domain_compatible(struct iommu_domain *domain, struct device *dev)
 	struct intel_iommu *iommu = info->iommu;
 	int ret = -EINVAL;
 
+#ifdef CONFIG_IOMMU_LIVEUPDATE
+	/*
+	 * Restored IOMMU domains are already attached to the device and can
+	 * only be freed. So no need to check the compatibility.
+	 */
+	if (iommu_domain_restored_state(domain)) {
+		if (!dev_iommu_restored_state(dev))
+			return -EINVAL;
+
+		return 0;
+	}
+#endif
+
 	if (intel_domain_is_fs_paging(dmar_domain))
 		ret = paging_domain_compatible_first_stage(dmar_domain, iommu);
 	else if (intel_domain_is_ss_paging(dmar_domain))
@@ -3969,6 +3992,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.page_response		= intel_iommu_page_response,
 #ifdef CONFIG_IOMMU_LIVEUPDATE
 	.preserve_device	= intel_iommu_preserve_device,
+	.unpreserve_device	= intel_iommu_unpreserve_device,
 	.preserve		= intel_iommu_preserve,
 	.unpreserve		= intel_iommu_unpreserve,
 #endif
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index a2c2cb86a7fc..be56bb73710e 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1290,6 +1290,8 @@ static inline int iopf_for_domain_replace(struct iommu_domain *new,
 #ifdef CONFIG_IOMMU_LIVEUPDATE
 int intel_iommu_preserve_device(struct device *dev,
 				struct iommu_device_ser *device_ser);
+void intel_iommu_unpreserve_device(struct device *dev,
+				   struct iommu_device_ser *device_ser);
 int intel_iommu_preserve(struct iommu_device *iommu,
 			 struct iommu_hw_ser *iommu_ser);
 void intel_iommu_unpreserve(struct iommu_device *iommu,
@@ -1297,6 +1299,9 @@ void intel_iommu_unpreserve(struct iommu_device *iommu,
 void clear_unpreserved_context_entries(struct intel_iommu *iommu);
 void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu,
 					       struct iommu_hw_ser *iommu_ser);
+int intel_iommu_domain_reattach_iommu(struct dmar_domain *domain,
+				      struct intel_iommu *iommu,
+				      struct iommu_device_ser *device_ser);
 #else
 static inline int intel_iommu_preserve_device(struct device *dev,
 					      struct iommu_device_ser *device_ser)
@@ -1304,6 +1309,11 @@ static inline int intel_iommu_preserve_device(struct device *dev,
 	return -EOPNOTSUPP;
 }
 
+static inline void intel_iommu_unpreserve_device(struct device *dev,
+						 struct iommu_device_ser *device_ser)
+{
+}
+
 static inline int intel_iommu_preserve(struct iommu_device *iommu,
 				       struct iommu_hw_ser *iommu_ser)
 {
@@ -1323,6 +1333,13 @@ static inline void intel_iommu_liveupdate_restore_root_table(struct intel_iommu
 							     struct iommu_hw_ser *iommu_ser)
 {
 }
+
+static inline int intel_iommu_domain_reattach_iommu(struct dmar_domain *domain,
+						    struct intel_iommu *iommu,
+						    struct iommu_device_ser *device_ser)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
diff --git a/drivers/iommu/intel/liveupdate.c b/drivers/iommu/intel/liveupdate.c
index 1a1868e6cc59..61d864a2e27c 100644
--- a/drivers/iommu/intel/liveupdate.c
+++ b/drivers/iommu/intel/liveupdate.c
@@ -254,6 +254,117 @@ void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu,
 	iommu_for_each_preserved_device(_restore_used_domain_ids, iommu);
 }
 
+int intel_iommu_domain_reattach_iommu(struct dmar_domain *domain,
+				      struct intel_iommu *iommu,
+				      struct iommu_device_ser *device_ser)
+{
+	struct iommu_domain_info *info, *curr;
+	int ret = -ENOSPC;
+	int restored_did;
+
+	if (domain->domain.type == IOMMU_DOMAIN_SVA)
+		return 0;
+
+	restored_did = device_ser->domain_iommu_ser.attachment_id;
+	if (!ida_exists(&iommu->domain_ida, restored_did))
+		return -EINVAL;
+
+	info = kzalloc_obj(*info);
+	if (!info)
+		return -ENOMEM;
+
+	guard(mutex)(&iommu->did_lock);
+	curr = xa_load(&domain->iommu_array, iommu->seq_id);
+	if (curr) {
+		curr->refcnt++;
+		kfree(info);
+		return 0;
+	}
+
+	info->refcnt	= 1;
+	info->did	= restored_did;
+	info->iommu	= iommu;
+	curr = xa_cmpxchg(&domain->iommu_array, iommu->seq_id,
+			  NULL, info, GFP_KERNEL);
+	if (curr) {
+		ret = xa_err(curr) ? : -EBUSY;
+		goto err_unlock;
+	}
+
+	return 0;
+
+err_unlock:
+	kfree(info);
+	return ret;
+}
+
+enum pasid_lu_op {
+	PASID_LU_OP_PRESERVE = 1,
+	PASID_LU_OP_UNPRESERVE,
+	PASID_LU_OP_RESTORE,
+	PASID_LU_OP_FREE,
+};
+
+static int pasid_lu_do_op(void *table, enum pasid_lu_op op)
+{
+	int ret = 0;
+
+	switch (op) {
+	case PASID_LU_OP_PRESERVE:
+		ret = iommu_preserve_pages(table);
+		break;
+	case PASID_LU_OP_UNPRESERVE:
+		iommu_unpreserve_pages(table);
+		break;
+	case PASID_LU_OP_RESTORE:
+		iommu_restore_pages(virt_to_phys(table));
+		break;
+	case PASID_LU_OP_FREE:
+		iommu_free_pages(table);
+		break;
+	}
+
+	return ret;
+}
+
+static int pasid_lu_handle_pd(struct pasid_dir_entry *dir,
+			      u32 max_pasid, enum pasid_lu_op op)
+{
+	int max_pde = max_pasid >> PASID_PDE_SHIFT;
+	struct pasid_entry *table;
+	int i, ret;
+
+	for (i = 0; i < max_pde; i++) {
+		table = get_pasid_table_from_pde(&dir[i]);
+		if (!table)
+			continue;
+
+		ret = pasid_lu_do_op(table, op);
+		if (ret)
+			goto err;
+	}
+
+	ret = pasid_lu_do_op(dir, op);
+	if (ret)
+		goto err;
+
+	return 0;
+
+err:
+	if (op != PASID_LU_OP_PRESERVE)
+		return ret;
+
+	for (; i >= 0; i--) {
+		table = get_pasid_table_from_pde(&dir[i]);
+		if (!table)
+			continue;
+
+		pasid_lu_do_op(table, PASID_LU_OP_UNPRESERVE);
+	}
+
+	return ret;
+}
+
 int intel_iommu_preserve_device(struct device *dev,
 				struct iommu_device_ser *device_ser)
 {
-- 
2.54.0.1136.gdb2ca164c4-goog