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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 D081DC282DD for ; Thu, 23 May 2019 18:57:00 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AF0A22175B for ; Thu, 23 May 2019 18:57:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF0A22175B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 75F34F30; Thu, 23 May 2019 18:57:00 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 1EE1EF27 for ; Thu, 23 May 2019 18:56:59 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 5E78B83A for ; Thu, 23 May 2019 18:56:58 +0000 (UTC) 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 E4AA1A78; Thu, 23 May 2019 11:56:57 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 07D6E3F5AF; Thu, 23 May 2019 11:56:55 -0700 (PDT) Subject: Re: [PATCH 3/4] iommu: Introduce device fault report API To: Jean-Philippe Brucker , joro@8bytes.org, alex.williamson@redhat.com References: <20190523180613.55049-1-jean-philippe.brucker@arm.com> <20190523180613.55049-4-jean-philippe.brucker@arm.com> From: Robin Murphy Message-ID: Date: Thu, 23 May 2019 19:56:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190523180613.55049-4-jean-philippe.brucker@arm.com> Content-Language: en-GB Cc: yi.l.liu@linux.intel.com, iommu@lists.linux-foundation.org, ashok.raj@intel.com, linux-kernel@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 23/05/2019 19:06, Jean-Philippe Brucker wrote: > 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); > + Note that this gets a bit tricky when we come to move to move the fwspec/ops/etc. into iommu_param, since that data can have a longer lifespan than the group association. I'd suggest moving this management out to the iommu_{probe,release}_device() level from the start, but maybe we're happy to come back and change things later as necessary. Robin. > 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; > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu