1 files changed, 238 insertions, 20 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 46a06ff46e47..0c674d80c37f 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1,19 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2007-2008 Advanced Micro Devices, Inc.
  * Author: Joerg Roedel <jroedel@suse.de>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
 #define pr_fmt(fmt)    "iommu: " fmt
@@ -108,15 +96,43 @@ void iommu_device_unregister(struct iommu_device *iommu)
 	spin_unlock(&iommu_device_lock);
 }
 
+static struct iommu_param *iommu_get_dev_param(struct device *dev)
+{
+	struct iommu_param *param = dev->iommu_param;
+
+	if (param)
+		return param;
+
+	param = kzalloc(sizeof(*param), GFP_KERNEL);
+	if (!param)
+		return NULL;
+
+	mutex_init(&param->lock);
+	dev->iommu_param = param;
+	return param;
+}
+
+static void iommu_free_dev_param(struct device *dev)
+{
+	kfree(dev->iommu_param);
+	dev->iommu_param = NULL;
+}
+
 int iommu_probe_device(struct device *dev)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
-	int ret = -EINVAL;
+	int ret;
 
 	WARN_ON(dev->iommu_group);
+	if (!ops)
+		return -EINVAL;
 
-	if (ops)
-		ret = ops->add_device(dev);
+	if (!iommu_get_dev_param(dev))
+		return -ENOMEM;
+
+	ret = ops->add_device(dev);
+	if (ret)
+		iommu_free_dev_param(dev);
 
 	return ret;
 }
@@ -127,6 +143,8 @@ void iommu_release_device(struct device *dev)
 
 	if (dev->iommu_group)
 		ops->remove_device(dev);
+
+	iommu_free_dev_param(dev);
 }
 
 static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
@@ -344,7 +362,7 @@ static ssize_t iommu_group_show_type(struct iommu_group *group,
 			type = "unmanaged\n";
 			break;
 		case IOMMU_DOMAIN_DMA:
-			type = "DMA";
+			type = "DMA\n";
 			break;
 		}
 	}
@@ -859,6 +877,206 @@ int iommu_group_unregister_notifier(struct iommu_group *group,
 EXPORT_SYMBOL_GPL(iommu_group_unregister_notifier);
 
 /**
+ * iommu_register_device_fault_handler() - Register a device fault handler
+ * @dev: the device
+ * @handler: the fault handler
+ * @data: private data passed as argument to the handler
+ *
+ * When an IOMMU fault event is received, this handler gets called with the
+ * fault event and data as argument. The handler should return 0 on success. If
+ * the fault is recoverable (IOMMU_FAULT_PAGE_REQ), the consumer should also
+ * complete the fault by calling iommu_page_response() with one of the following
+ * response code:
+ * - IOMMU_PAGE_RESP_SUCCESS: retry the translation
+ * - IOMMU_PAGE_RESP_INVALID: terminate the fault
+ * - IOMMU_PAGE_RESP_FAILURE: terminate the fault and stop reporting
+ *   page faults if possible.
+ *
+ * Return 0 if the fault handler was installed successfully, or an error.
+ */
+int iommu_register_device_fault_handler(struct device *dev,
+					iommu_dev_fault_handler_t handler,
+					void *data)
+{
+	struct iommu_param *param = dev->iommu_param;
+	int ret = 0;
+
+	if (!param)
+		return -EINVAL;
+
+	mutex_lock(&param->lock);
+	/* Only allow one fault handler registered for each device */
+	if (param->fault_param) {
+		ret = -EBUSY;
+		goto done_unlock;
+	}
+
+	get_device(dev);
+	param->fault_param = kzalloc(sizeof(*param->fault_param), GFP_KERNEL);
+	if (!param->fault_param) {
+		put_device(dev);
+		ret = -ENOMEM;
+		goto done_unlock;
+	}
+	param->fault_param->handler = handler;
+	param->fault_param->data = data;
+	mutex_init(&param->fault_param->lock);
+	INIT_LIST_HEAD(&param->fault_param->faults);
+
+done_unlock:
+	mutex_unlock(&param->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_register_device_fault_handler);
+
+/**
+ * iommu_unregister_device_fault_handler() - Unregister the device fault handler
+ * @dev: the device
+ *
+ * Remove the device fault handler installed with
+ * iommu_register_device_fault_handler().
+ *
+ * Return 0 on success, or an error.
+ */
+int iommu_unregister_device_fault_handler(struct device *dev)
+{
+	struct iommu_param *param = dev->iommu_param;
+	int ret = 0;
+
+	if (!param)
+		return -EINVAL;
+
+	mutex_lock(&param->lock);
+
+	if (!param->fault_param)
+		goto unlock;
+
+	/* we cannot unregister handler if there are pending faults */
+	if (!list_empty(&param->fault_param->faults)) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	kfree(param->fault_param);
+	param->fault_param = NULL;
+	put_device(dev);
+unlock:
+	mutex_unlock(&param->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_unregister_device_fault_handler);
+
+/**
+ * iommu_report_device_fault() - Report fault event to device driver
+ * @dev: the device
+ * @evt: fault event data
+ *
+ * Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ
+ * handler. When this function fails and the fault is recoverable, it is the
+ * caller's responsibility to complete the fault.
+ *
+ * Return 0 on success, or an error.
+ */
+int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
+{
+	struct iommu_param *param = dev->iommu_param;
+	struct iommu_fault_event *evt_pending = NULL;
+	struct iommu_fault_param *fparam;
+	int ret = 0;
+
+	if (!param || !evt)
+		return -EINVAL;
+
+	/* we only report device fault if there is a handler registered */
+	mutex_lock(&param->lock);
+	fparam = param->fault_param;
+	if (!fparam || !fparam->handler) {
+		ret = -EINVAL;
+		goto done_unlock;
+	}
+
+	if (evt->fault.type == IOMMU_FAULT_PAGE_REQ &&
+	    (evt->fault.prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) {
+		evt_pending = kmemdup(evt, sizeof(struct iommu_fault_event),
+				      GFP_KERNEL);
+		if (!evt_pending) {
+			ret = -ENOMEM;
+			goto done_unlock;
+		}
+		mutex_lock(&fparam->lock);
+		list_add_tail(&evt_pending->list, &fparam->faults);
+		mutex_unlock(&fparam->lock);
+	}
+
+	ret = fparam->handler(&evt->fault, fparam->data);
+	if (ret && evt_pending) {
+		mutex_lock(&fparam->lock);
+		list_del(&evt_pending->list);
+		mutex_unlock(&fparam->lock);
+		kfree(evt_pending);
+	}
+done_unlock:
+	mutex_unlock(&param->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_report_device_fault);
+
+int iommu_page_response(struct device *dev,
+			struct iommu_page_response *msg)
+{
+	bool pasid_valid;
+	int ret = -EINVAL;
+	struct iommu_fault_event *evt;
+	struct iommu_fault_page_request *prm;
+	struct iommu_param *param = dev->iommu_param;
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+
+	if (!domain || !domain->ops->page_response)
+		return -ENODEV;
+
+	if (!param || !param->fault_param)
+		return -EINVAL;
+
+	if (msg->version != IOMMU_PAGE_RESP_VERSION_1 ||
+	    msg->flags & ~IOMMU_PAGE_RESP_PASID_VALID)
+		return -EINVAL;
+
+	/* Only send response if there is a fault report pending */
+	mutex_lock(&param->fault_param->lock);
+	if (list_empty(&param->fault_param->faults)) {
+		dev_warn_ratelimited(dev, "no pending PRQ, drop response\n");
+		goto done_unlock;
+	}
+	/*
+	 * Check if we have a matching page request pending to respond,
+	 * otherwise return -EINVAL
+	 */
+	list_for_each_entry(evt, &param->fault_param->faults, list) {
+		prm = &evt->fault.prm;
+		pasid_valid = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+
+		if ((pasid_valid && prm->pasid != msg->pasid) ||
+		    prm->grpid != msg->grpid)
+			continue;
+
+		/* Sanitize the reply */
+		msg->flags = pasid_valid ? IOMMU_PAGE_RESP_PASID_VALID : 0;
+
+		ret = domain->ops->page_response(dev, evt, msg);
+		list_del(&evt->list);
+		kfree(evt);
+		break;
+	}
+
+done_unlock:
+	mutex_unlock(&param->fault_param->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_page_response);
+
+/**
  * iommu_group_id - Return ID for a group
  * @group: the group to ID
  *
@@ -1919,9 +2137,9 @@ request_default_domain_for_dev(struct device *dev, unsigned long type)
 	int ret;
 
 	/* Device must already be in a group before calling this function */
-	group = iommu_group_get_for_dev(dev);
-	if (IS_ERR(group))
-		return PTR_ERR(group);
+	group = iommu_group_get(dev);
+	if (!group)
+		return -EINVAL;
 
 	mutex_lock(&group->mutex);