From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF323C282DD for ; Thu, 23 May 2019 18:07:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C52FE2075B for ; Thu, 23 May 2019 18:07:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387517AbfEWSHM (ORCPT ); Thu, 23 May 2019 14:07:12 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:52116 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387500AbfEWSHK (ORCPT ); Thu, 23 May 2019 14:07:10 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6A41D1682; Thu, 23 May 2019 11:07:09 -0700 (PDT) Received: from ostrya.cambridge.arm.com (ostrya.cambridge.arm.com [10.1.196.129]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C0BCC3F5AF; Thu, 23 May 2019 11:07:07 -0700 (PDT) From: Jean-Philippe Brucker To: joro@8bytes.org, alex.williamson@redhat.com Cc: jacob.jun.pan@linux.intel.com, eric.auger@redhat.com, ashok.raj@intel.com, yi.l.liu@linux.intel.com, robdclark@gmail.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: [PATCH 3/4] iommu: Introduce device fault report API Date: Thu, 23 May 2019 19:06:12 +0100 Message-Id: <20190523180613.55049-4-jean-philippe.brucker@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190523180613.55049-1-jean-philippe.brucker@arm.com> References: <20190523180613.55049-1-jean-philippe.brucker@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jacob Pan Traditionally, device specific faults are detected and handled within their own device drivers. When IOMMU is enabled, faults such as DMA related transactions are detected by IOMMU. There is no generic reporting mechanism to report faults back to the in-kernel device driver or the guest OS in case of assigned devices. This patch introduces a registration API for device specific fault handlers. This differs from the existing iommu_set_fault_handler/ report_iommu_fault infrastructures in several ways: - it allows to report more sophisticated fault events (both unrecoverable faults and page request faults) due to the nature of the iommu_fault struct - it is device specific and not domain specific. The current iommu_report_device_fault() implementation only handles the "shoot and forget" unrecoverable fault case. Handling of page request faults or stalled faults will come later. Signed-off-by: Jacob Pan Signed-off-by: Ashok Raj Signed-off-by: Jean-Philippe Brucker Signed-off-by: Eric Auger --- drivers/iommu/iommu.c | 127 ++++++++++++++++++++++++++++++++++++++++++ include/linux/iommu.h | 29 ++++++++++ 2 files changed, 156 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 67ee6623f9b2..d546f7baa0d4 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -644,6 +644,13 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev) goto err_free_name; } + dev->iommu_param = kzalloc(sizeof(*dev->iommu_param), GFP_KERNEL); + if (!dev->iommu_param) { + ret = -ENOMEM; + goto err_free_name; + } + mutex_init(&dev->iommu_param->lock); + kobject_get(group->devices_kobj); dev->iommu_group = group; @@ -674,6 +681,8 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev) mutex_unlock(&group->mutex); dev->iommu_group = NULL; kobject_put(group->devices_kobj); + kfree(dev->iommu_param); + dev->iommu_param = NULL; err_free_name: kfree(device->name); err_remove_link: @@ -721,6 +730,8 @@ void iommu_group_remove_device(struct device *dev) trace_remove_device_from_group(group->id, dev); + kfree(dev->iommu_param); + dev->iommu_param = NULL; kfree(device->name); kfree(device); dev->iommu_group = NULL; @@ -854,6 +865,122 @@ 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. + * + * 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; + + /* + * Device iommu_param should have been allocated when device is + * added to its iommu_group. + */ + if (!param) + return -EINVAL; + + mutex_lock(¶m->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(struct iommu_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; + +done_unlock: + mutex_unlock(¶m->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(¶m->lock); + + if (!param->fault_param) + goto unlock; + + kfree(param->fault_param); + param->fault_param = NULL; + put_device(dev); +unlock: + mutex_unlock(¶m->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. + * + * 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_param *fparam; + int ret = 0; + + /* iommu_param is allocated when device is added to group */ + if (!param || !evt) + return -EINVAL; + + /* we only report device fault if there is a handler registered */ + mutex_lock(¶m->lock); + fparam = param->fault_param; + if (!fparam || !fparam->handler) { + ret = -EINVAL; + goto done_unlock; + } + ret = fparam->handler(evt, fparam->data); +done_unlock: + mutex_unlock(¶m->lock); + return ret; +} +EXPORT_SYMBOL_GPL(iommu_report_device_fault); + /** * iommu_group_id - Return ID for a group * @group: the group to ID diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d442f5f3fa93..f95e376a7ed3 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -340,6 +340,7 @@ struct iommu_fault_param { * struct iommu_fwspec *iommu_fwspec; */ struct iommu_param { + struct mutex lock; struct iommu_fault_param *fault_param; }; @@ -432,6 +433,15 @@ extern int iommu_group_register_notifier(struct iommu_group *group, struct notifier_block *nb); extern int iommu_group_unregister_notifier(struct iommu_group *group, struct notifier_block *nb); +extern int iommu_register_device_fault_handler(struct device *dev, + iommu_dev_fault_handler_t handler, + void *data); + +extern int iommu_unregister_device_fault_handler(struct device *dev); + +extern int iommu_report_device_fault(struct device *dev, + struct iommu_fault_event *evt); + extern int iommu_group_id(struct iommu_group *group); extern struct iommu_group *iommu_group_get_for_dev(struct device *dev); extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *); @@ -740,6 +750,25 @@ static inline int iommu_group_unregister_notifier(struct iommu_group *group, return 0; } +static inline +int iommu_register_device_fault_handler(struct device *dev, + iommu_dev_fault_handler_t handler, + void *data) +{ + return -ENODEV; +} + +static inline int iommu_unregister_device_fault_handler(struct device *dev) +{ + return 0; +} + +static inline +int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt) +{ + return -ENODEV; +} + static inline int iommu_group_id(struct iommu_group *group) { return -ENODEV; -- 2.21.0