diff options
Diffstat (limited to 'drivers/iommu/io-pgfault.c')
-rw-r--r-- | drivers/iommu/io-pgfault.c | 463 |
1 files changed, 269 insertions, 194 deletions
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c index e5b8b9110c13..06d78fcc79fd 100644 --- a/drivers/iommu/io-pgfault.c +++ b/drivers/iommu/io-pgfault.c @@ -11,101 +11,140 @@ #include <linux/slab.h> #include <linux/workqueue.h> -#include "iommu-sva.h" +#include "iommu-priv.h" -/** - * struct iopf_queue - IO Page Fault queue - * @wq: the fault workqueue - * @devices: devices attached to this queue - * @lock: protects the device list +/* + * Return the fault parameter of a device if it exists. Otherwise, return NULL. + * On a successful return, the caller takes a reference of this parameter and + * should put it after use by calling iopf_put_dev_fault_param(). */ -struct iopf_queue { - struct workqueue_struct *wq; - struct list_head devices; - struct mutex lock; -}; +static struct iommu_fault_param *iopf_get_dev_fault_param(struct device *dev) +{ + struct dev_iommu *param = dev->iommu; + struct iommu_fault_param *fault_param; -/** - * struct iopf_device_param - IO Page Fault data attached to a device - * @dev: the device that owns this param - * @queue: IOPF queue - * @queue_list: index into queue->devices - * @partial: faults that are part of a Page Request Group for which the last - * request hasn't been submitted yet. - */ -struct iopf_device_param { - struct device *dev; - struct iopf_queue *queue; - struct list_head queue_list; - struct list_head partial; -}; - -struct iopf_fault { - struct iommu_fault fault; - struct list_head list; -}; - -struct iopf_group { - struct iopf_fault last_fault; - struct list_head faults; - struct work_struct work; - struct device *dev; -}; - -static int iopf_complete_group(struct device *dev, struct iopf_fault *iopf, - enum iommu_page_response_code status) + rcu_read_lock(); + fault_param = rcu_dereference(param->fault_param); + if (fault_param && !refcount_inc_not_zero(&fault_param->users)) + fault_param = NULL; + rcu_read_unlock(); + + return fault_param; +} + +/* Caller must hold a reference of the fault parameter. */ +static void iopf_put_dev_fault_param(struct iommu_fault_param *fault_param) { - struct iommu_page_response resp = { - .version = IOMMU_PAGE_RESP_VERSION_1, - .pasid = iopf->fault.prm.pasid, - .grpid = iopf->fault.prm.grpid, - .code = status, - }; + if (refcount_dec_and_test(&fault_param->users)) + kfree_rcu(fault_param, rcu); +} - if ((iopf->fault.prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) && - (iopf->fault.prm.flags & IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID)) - resp.flags = IOMMU_PAGE_RESP_PASID_VALID; +static void __iopf_free_group(struct iopf_group *group) +{ + struct iopf_fault *iopf, *next; - return iommu_page_response(dev, &resp); + list_for_each_entry_safe(iopf, next, &group->faults, list) { + if (!(iopf->fault.prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) + kfree(iopf); + } + + /* Pair with iommu_report_device_fault(). */ + iopf_put_dev_fault_param(group->fault_param); } -static void iopf_handler(struct work_struct *work) +void iopf_free_group(struct iopf_group *group) +{ + __iopf_free_group(group); + kfree(group); +} +EXPORT_SYMBOL_GPL(iopf_free_group); + +static struct iommu_domain *get_domain_for_iopf(struct device *dev, + struct iommu_fault *fault) { - struct iopf_group *group; struct iommu_domain *domain; - struct iopf_fault *iopf, *next; - enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS; - group = container_of(work, struct iopf_group, work); - domain = iommu_get_domain_for_dev_pasid(group->dev, - group->last_fault.fault.prm.pasid, 0); - if (!domain || !domain->iopf_handler) - status = IOMMU_PAGE_RESP_INVALID; + if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) { + domain = iommu_get_domain_for_dev_pasid(dev, fault->prm.pasid, 0); + if (IS_ERR(domain)) + domain = NULL; + } else { + domain = iommu_get_domain_for_dev(dev); + } - list_for_each_entry_safe(iopf, next, &group->faults, list) { + if (!domain || !domain->iopf_handler) { + dev_warn_ratelimited(dev, + "iopf (pasid %d) without domain attached or handler installed\n", + fault->prm.pasid); + + return NULL; + } + + return domain; +} + +/* Non-last request of a group. Postpone until the last one. */ +static int report_partial_fault(struct iommu_fault_param *fault_param, + struct iommu_fault *fault) +{ + struct iopf_fault *iopf; + + iopf = kzalloc(sizeof(*iopf), GFP_KERNEL); + if (!iopf) + return -ENOMEM; + + iopf->fault = *fault; + + mutex_lock(&fault_param->lock); + list_add(&iopf->list, &fault_param->partial); + mutex_unlock(&fault_param->lock); + + return 0; +} + +static struct iopf_group *iopf_group_alloc(struct iommu_fault_param *iopf_param, + struct iopf_fault *evt, + struct iopf_group *abort_group) +{ + struct iopf_fault *iopf, *next; + struct iopf_group *group; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + if (!group) { /* - * For the moment, errors are sticky: don't handle subsequent - * faults in the group if there is an error. + * We always need to construct the group as we need it to abort + * the request at the driver if it can't be handled. */ - if (status == IOMMU_PAGE_RESP_SUCCESS) - status = domain->iopf_handler(&iopf->fault, - domain->fault_data); + group = abort_group; + } - if (!(iopf->fault.prm.flags & - IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) - kfree(iopf); + group->fault_param = iopf_param; + group->last_fault.fault = evt->fault; + INIT_LIST_HEAD(&group->faults); + INIT_LIST_HEAD(&group->pending_node); + list_add(&group->last_fault.list, &group->faults); + + /* See if we have partial faults for this group */ + mutex_lock(&iopf_param->lock); + list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) { + if (iopf->fault.prm.grpid == evt->fault.prm.grpid) + /* Insert *before* the last fault */ + list_move(&iopf->list, &group->faults); } + list_add(&group->pending_node, &iopf_param->faults); + mutex_unlock(&iopf_param->lock); - iopf_complete_group(group->dev, &group->last_fault, status); - kfree(group); + return group; } /** - * iommu_queue_iopf - IO Page Fault handler - * @fault: fault event - * @cookie: struct device, passed to iommu_register_device_fault_handler. + * iommu_report_device_fault() - Report fault event to device driver + * @dev: the device + * @evt: fault event data * - * Add a fault to the device workqueue, to be handled by mm. + * Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ + * handler. If this function fails then ops->page_response() was called to + * complete evt if required. * * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't @@ -137,83 +176,57 @@ static void iopf_handler(struct work_struct *work) * freed after the device has stopped generating page faults (or the iommu * hardware has been set to block the page faults) and the pending page faults * have been flushed. - * - * Return: 0 on success and <0 on error. */ -int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) +void iommu_report_device_fault(struct device *dev, struct iopf_fault *evt) { - int ret; + struct iommu_fault *fault = &evt->fault; + struct iommu_fault_param *iopf_param; + struct iopf_group abort_group = {}; struct iopf_group *group; - struct iopf_fault *iopf, *next; - struct iopf_device_param *iopf_param; - struct device *dev = cookie; - struct dev_iommu *param = dev->iommu; - - lockdep_assert_held(¶m->lock); - - if (fault->type != IOMMU_FAULT_PAGE_REQ) - /* Not a recoverable page fault */ - return -EOPNOTSUPP; - - /* - * As long as we're holding param->lock, the queue can't be unlinked - * from the device and therefore cannot disappear. - */ - iopf_param = param->iopf_param; - if (!iopf_param) - return -ENODEV; + iopf_param = iopf_get_dev_fault_param(dev); + if (WARN_ON(!iopf_param)) + return; if (!(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) { - iopf = kzalloc(sizeof(*iopf), GFP_KERNEL); - if (!iopf) - return -ENOMEM; - - iopf->fault = *fault; - - /* Non-last request of a group. Postpone until the last one */ - list_add(&iopf->list, &iopf_param->partial); - - return 0; + report_partial_fault(iopf_param, fault); + iopf_put_dev_fault_param(iopf_param); + /* A request that is not the last does not need to be ack'd */ } - group = kzalloc(sizeof(*group), GFP_KERNEL); - if (!group) { - /* - * The caller will send a response to the hardware. But we do - * need to clean up before leaving, otherwise partial faults - * will be stuck. - */ - ret = -ENOMEM; - goto cleanup_partial; - } + /* + * This is the last page fault of a group. Allocate an iopf group and + * pass it to domain's page fault handler. The group holds a reference + * count of the fault parameter. It will be released after response or + * error path of this function. If an error is returned, the caller + * will send a response to the hardware. We need to clean up before + * leaving, otherwise partial faults will be stuck. + */ + group = iopf_group_alloc(iopf_param, evt, &abort_group); + if (group == &abort_group) + goto err_abort; - group->dev = dev; - group->last_fault.fault = *fault; - INIT_LIST_HEAD(&group->faults); - list_add(&group->last_fault.list, &group->faults); - INIT_WORK(&group->work, iopf_handler); + group->domain = get_domain_for_iopf(dev, fault); + if (!group->domain) + goto err_abort; - /* See if we have partial faults for this group */ - list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) { - if (iopf->fault.prm.grpid == fault->prm.grpid) - /* Insert *before* the last fault */ - list_move(&iopf->list, &group->faults); - } + /* + * On success iopf_handler must call iopf_group_response() and + * iopf_free_group() + */ + if (group->domain->iopf_handler(group)) + goto err_abort; - queue_work(iopf_param->queue->wq, &group->work); - return 0; + return; -cleanup_partial: - list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) { - if (iopf->fault.prm.grpid == fault->prm.grpid) { - list_del(&iopf->list); - kfree(iopf); - } - } - return ret; +err_abort: + iopf_group_response(group, IOMMU_PAGE_RESP_FAILURE); + if (group == &abort_group) + __iopf_free_group(group); + else + iopf_free_group(group); } -EXPORT_SYMBOL_GPL(iommu_queue_iopf); +EXPORT_SYMBOL_GPL(iommu_report_device_fault); /** * iopf_queue_flush_dev - Ensure that all queued faults have been processed @@ -229,26 +242,52 @@ EXPORT_SYMBOL_GPL(iommu_queue_iopf); */ int iopf_queue_flush_dev(struct device *dev) { - int ret = 0; - struct iopf_device_param *iopf_param; - struct dev_iommu *param = dev->iommu; + struct iommu_fault_param *iopf_param; - if (!param) + /* + * It's a driver bug to be here after iopf_queue_remove_device(). + * Therefore, it's safe to dereference the fault parameter without + * holding the lock. + */ + iopf_param = rcu_dereference_check(dev->iommu->fault_param, true); + if (WARN_ON(!iopf_param)) return -ENODEV; - mutex_lock(¶m->lock); - iopf_param = param->iopf_param; - if (iopf_param) - flush_workqueue(iopf_param->queue->wq); - else - ret = -ENODEV; - mutex_unlock(¶m->lock); + flush_workqueue(iopf_param->queue->wq); - return ret; + return 0; } EXPORT_SYMBOL_GPL(iopf_queue_flush_dev); /** + * iopf_group_response - Respond a group of page faults + * @group: the group of faults with the same group id + * @status: the response code + */ +void iopf_group_response(struct iopf_group *group, + enum iommu_page_response_code status) +{ + struct iommu_fault_param *fault_param = group->fault_param; + struct iopf_fault *iopf = &group->last_fault; + struct device *dev = group->fault_param->dev; + const struct iommu_ops *ops = dev_iommu_ops(dev); + struct iommu_page_response resp = { + .pasid = iopf->fault.prm.pasid, + .grpid = iopf->fault.prm.grpid, + .code = status, + }; + + /* Only send response if there is a fault report pending */ + mutex_lock(&fault_param->lock); + if (!list_empty(&group->pending_node)) { + ops->page_response(dev, &group->last_fault, &resp); + list_del_init(&group->pending_node); + } + mutex_unlock(&fault_param->lock); +} +EXPORT_SYMBOL_GPL(iopf_group_response); + +/** * iopf_queue_discard_partial - Remove all pending partial fault * @queue: the queue whose partial faults need to be discarded * @@ -261,18 +300,20 @@ EXPORT_SYMBOL_GPL(iopf_queue_flush_dev); int iopf_queue_discard_partial(struct iopf_queue *queue) { struct iopf_fault *iopf, *next; - struct iopf_device_param *iopf_param; + struct iommu_fault_param *iopf_param; if (!queue) return -EINVAL; mutex_lock(&queue->lock); list_for_each_entry(iopf_param, &queue->devices, queue_list) { + mutex_lock(&iopf_param->lock); list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) { list_del(&iopf->list); kfree(iopf); } + mutex_unlock(&iopf_param->lock); } mutex_unlock(&queue->lock); return 0; @@ -288,34 +329,42 @@ EXPORT_SYMBOL_GPL(iopf_queue_discard_partial); */ int iopf_queue_add_device(struct iopf_queue *queue, struct device *dev) { - int ret = -EBUSY; - struct iopf_device_param *iopf_param; + int ret = 0; struct dev_iommu *param = dev->iommu; + struct iommu_fault_param *fault_param; + const struct iommu_ops *ops = dev_iommu_ops(dev); - if (!param) + if (!ops->page_response) return -ENODEV; - iopf_param = kzalloc(sizeof(*iopf_param), GFP_KERNEL); - if (!iopf_param) - return -ENOMEM; - - INIT_LIST_HEAD(&iopf_param->partial); - iopf_param->queue = queue; - iopf_param->dev = dev; - mutex_lock(&queue->lock); mutex_lock(¶m->lock); - if (!param->iopf_param) { - list_add(&iopf_param->queue_list, &queue->devices); - param->iopf_param = iopf_param; - ret = 0; + if (rcu_dereference_check(param->fault_param, + lockdep_is_held(¶m->lock))) { + ret = -EBUSY; + goto done_unlock; + } + + fault_param = kzalloc(sizeof(*fault_param), GFP_KERNEL); + if (!fault_param) { + ret = -ENOMEM; + goto done_unlock; } + + mutex_init(&fault_param->lock); + INIT_LIST_HEAD(&fault_param->faults); + INIT_LIST_HEAD(&fault_param->partial); + fault_param->dev = dev; + refcount_set(&fault_param->users, 1); + list_add(&fault_param->queue_list, &queue->devices); + fault_param->queue = queue; + + rcu_assign_pointer(param->fault_param, fault_param); + +done_unlock: mutex_unlock(¶m->lock); mutex_unlock(&queue->lock); - if (ret) - kfree(iopf_param); - return ret; } EXPORT_SYMBOL_GPL(iopf_queue_add_device); @@ -325,40 +374,66 @@ EXPORT_SYMBOL_GPL(iopf_queue_add_device); * @queue: IOPF queue * @dev: device to remove * - * Caller makes sure that no more faults are reported for this device. + * Removing a device from an iopf_queue. It's recommended to follow these + * steps when removing a device: * - * Return: 0 on success and <0 on error. + * - Disable new PRI reception: Turn off PRI generation in the IOMMU hardware + * and flush any hardware page request queues. This should be done before + * calling into this helper. + * - Acknowledge all outstanding PRQs to the device: Respond to all outstanding + * page requests with IOMMU_PAGE_RESP_INVALID, indicating the device should + * not retry. This helper function handles this. + * - Disable PRI on the device: After calling this helper, the caller could + * then disable PRI on the device. + * + * Calling iopf_queue_remove_device() essentially disassociates the device. + * The fault_param might still exist, but iommu_page_response() will do + * nothing. The device fault parameter reference count has been properly + * passed from iommu_report_device_fault() to the fault handling work, and + * will eventually be released after iommu_page_response(). */ -int iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) +void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) { - int ret = -EINVAL; - struct iopf_fault *iopf, *next; - struct iopf_device_param *iopf_param; + struct iopf_fault *partial_iopf; + struct iopf_fault *next; + struct iopf_group *group, *temp; struct dev_iommu *param = dev->iommu; - - if (!param || !queue) - return -EINVAL; + struct iommu_fault_param *fault_param; + const struct iommu_ops *ops = dev_iommu_ops(dev); mutex_lock(&queue->lock); mutex_lock(¶m->lock); - iopf_param = param->iopf_param; - if (iopf_param && iopf_param->queue == queue) { - list_del(&iopf_param->queue_list); - param->iopf_param = NULL; - ret = 0; + fault_param = rcu_dereference_check(param->fault_param, + lockdep_is_held(¶m->lock)); + + if (WARN_ON(!fault_param || fault_param->queue != queue)) + goto unlock; + + mutex_lock(&fault_param->lock); + list_for_each_entry_safe(partial_iopf, next, &fault_param->partial, list) + kfree(partial_iopf); + + list_for_each_entry_safe(group, temp, &fault_param->faults, pending_node) { + struct iopf_fault *iopf = &group->last_fault; + struct iommu_page_response resp = { + .pasid = iopf->fault.prm.pasid, + .grpid = iopf->fault.prm.grpid, + .code = IOMMU_PAGE_RESP_INVALID + }; + + ops->page_response(dev, iopf, &resp); + list_del_init(&group->pending_node); } - mutex_unlock(¶m->lock); - mutex_unlock(&queue->lock); - if (ret) - return ret; + mutex_unlock(&fault_param->lock); - /* Just in case some faults are still stuck */ - list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) - kfree(iopf); + list_del(&fault_param->queue_list); - kfree(iopf_param); - - return 0; + /* dec the ref owned by iopf_queue_add_device() */ + rcu_assign_pointer(param->fault_param, NULL); + iopf_put_dev_fault_param(fault_param); +unlock: + mutex_unlock(¶m->lock); + mutex_unlock(&queue->lock); } EXPORT_SYMBOL_GPL(iopf_queue_remove_device); @@ -404,7 +479,7 @@ EXPORT_SYMBOL_GPL(iopf_queue_alloc); */ void iopf_queue_free(struct iopf_queue *queue) { - struct iopf_device_param *iopf_param, *next; + struct iommu_fault_param *iopf_param, *next; if (!queue) return; |