From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZrUECiKzkW2Mr9lt5X0aD/62c9rcjtQ0JwKKATD73Pn9iaoohTKdZbBAPLxr400bvF1slfe ARC-Seal: i=1; a=rsa-sha256; t=1526277669; cv=none; d=google.com; s=arc-20160816; b=ut7DgxEjE3Tfmw6HJ2ZbJoqVNzIlk1WTzqs/W5EuEno+SlxtC2WZsJzX1K1IsnbrDF ezMYJj389r9IDRbjAyWHfOijmYdnWSrtOA7NRhoaXLWolX3HZi1aMIbHWJl0HhVZXE7c 8yClwpAmEsZdD+KWz04VkeKN+jhvONGy9hnG4gd9U9s1WitLM6LLOSqy0RzKBg6GlLYG 3KYXIo+Js9L2mdXouMBvnaN1s4AgEW0cER/BsSV8fuWOeYBEgXFGxm7fmYzRRMNojpSO JsWWseSf0igJ9umqH8cPVIRhYb5a/6yAcjWZX35zy7pqTvrcg7uwH9xvvmoUJYXUCaXb pdUg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:in-reply-to:mime-version:user-agent:date :message-id:from:cc:references:to:subject:arc-authentication-results; bh=4Hn/KZAdNT4ZvV/8D+jWrCt8mcr1cqQl6nW4oid1FvA=; b=od+k/jxY0MbDYWpcFi6dU08qJY/sDpyUxxKNBOFTbbnh2G5gu4Q0QVP/opcyrp3/K6 IEZjicLMT3TyL6j+iF+15+OtJLK24dxsB/ctjvYYCmpcRiYS1ZtWmuNPzSgas/CJl4E7 DCYOWTnY1P1QABZQAHV9iedvbMX6zO1emUd5PFv5KzrTVksVlMTldKJz4Ttv26JZxXi8 03y/0v+5syMPtqwQzdt9wYn+MjnP/nrnfpGS3vWyJQONUjaPUdzee0DWcVie4LtqzQmO N+ZnBZ7dSWkLfWgBkD70+43mX/Yq36icIN5Nv3JkbxVV4lDi7CCqDuKUWcnh2bjcrApA H6Jw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of baolu.lu@linux.intel.com designates 134.134.136.126 as permitted sender) smtp.mailfrom=baolu.lu@linux.intel.com Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of baolu.lu@linux.intel.com designates 134.134.136.126 as permitted sender) smtp.mailfrom=baolu.lu@linux.intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,398,1520924400"; d="scan'208";a="55640250" Subject: Re: [PATCH v5 13/23] iommu: introduce device fault report API To: Jacob Pan , iommu@lists.linux-foundation.org, LKML , Joerg Roedel , David Woodhouse , Greg Kroah-Hartman , Alex Williamson , Jean-Philippe Brucker References: <1526072055-86990-1-git-send-email-jacob.jun.pan@linux.intel.com> <1526072055-86990-14-git-send-email-jacob.jun.pan@linux.intel.com> Cc: Rafael Wysocki , "Liu, Yi L" , "Tian, Kevin" , Raj Ashok , Jean Delvare , Christoph Hellwig From: Lu Baolu Message-ID: <5AF92622.2090902@linux.intel.com> Date: Mon, 14 May 2018 14:01:06 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1526072055-86990-14-git-send-email-jacob.jun.pan@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600202363226135285?= X-GMAIL-MSGID: =?utf-8?q?1600418133230911628?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi, On 05/12/2018 04:54 AM, Jacob Pan wrote: > 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. > > Faults detected by IOMMU is based on the transaction's source ID which > can be reported at per device basis, regardless of the device type is a > PCI device or not. > > The fault types include recoverable (e.g. page request) and > unrecoverable faults(e.g. access error). In most cases, faults can be > handled by IOMMU drivers internally. The primary use cases are as > follows: > 1. page request fault originated from an SVM capable device that is > assigned to guest via vIOMMU. In this case, the first level page tables > are owned by the guest. Page request must be propagated to the guest to > let guest OS fault in the pages then send page response. In this > mechanism, the direct receiver of IOMMU fault notification is VFIO, > which can relay notification events to QEMU or other user space > software. > > 2. faults need more subtle handling by device drivers. Other than > simply invoke reset function, there are needs to let device driver > handle the fault with a smaller impact. > > This patchset is intended to create a generic fault report API such > that it can scale as follows: > - all IOMMU types > - PCI and non-PCI devices > - recoverable and unrecoverable faults > - VFIO and other other in kernel users > - DMA & IRQ remapping (TBD) > The original idea was brought up by David Woodhouse and discussions > summarized at https://lwn.net/Articles/608914/. > > Signed-off-by: Jacob Pan > Signed-off-by: Ashok Raj > Signed-off-by: Jean-Philippe Brucker > --- > drivers/iommu/iommu.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++++- > include/linux/iommu.h | 35 +++++++++++- > 2 files changed, 181 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 3a49b96..b3f9daf 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -609,6 +609,13 @@ 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; > @@ -639,6 +646,7 @@ 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); > err_free_name: > kfree(device->name); > err_remove_link: > @@ -685,7 +693,7 @@ void iommu_group_remove_device(struct device *dev) > sysfs_remove_link(&dev->kobj, "iommu_group"); > > trace_remove_device_from_group(group->id, dev); > - > + kfree(dev->iommu_param); > kfree(device->name); > kfree(device); > dev->iommu_group = NULL; > @@ -820,6 +828,145 @@ 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, call this handler 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 handler can 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; > + > + /* > + * 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; > + } > + mutex_init(¶m->fault_param->lock); Do we really need this mutex lock? Is param->lock enough? > + param->fault_param->handler = handler; > + param->fault_param->data = data; > + INIT_LIST_HEAD(¶m->fault_param->faults); > + > +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); > + /* we cannot unregister handler if there are pending faults */ > + if (!list_empty(¶m->fault_param->faults)) { > + ret = -EBUSY; > + 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 > + * @dev: the device > + * @evt: fault event data > + * > + * Called by IOMMU model specific drivers when 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) > +{ > + int ret = 0; > + struct iommu_fault_event *evt_pending; > + struct iommu_fault_param *fparam; > + > + /* iommu_param is allocated when device is added to group */ > + if (!dev->iommu_param | !evt) > + return -EINVAL; > + /* we only report device fault if there is a handler registered */ > + mutex_lock(&dev->iommu_param->lock); > + if (!dev->iommu_param->fault_param || > + !dev->iommu_param->fault_param->handler) { > + ret = -EINVAL; > + goto done_unlock; > + } > + fparam = dev->iommu_param->fault_param; > + if (evt->type == IOMMU_FAULT_PAGE_REQ && evt->last_req) { > + 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, fparam->data); > +done_unlock: > + mutex_unlock(&dev->iommu_param->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 aeadb4f..b3312ee 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -307,7 +307,8 @@ enum iommu_fault_reason { > * and PASID spec. > * - Un-recoverable faults of device interest > * - DMA remapping and IRQ remapping faults > - > + * > + * @list pending fault event list, used for tracking responses > * @type contains fault type. > * @reason fault reasons if relevant outside IOMMU driver, IOMMU driver internal > * faults are not reported > @@ -324,6 +325,7 @@ enum iommu_fault_reason { > * sending the fault response. > */ > struct iommu_fault_event { > + struct list_head list; > enum iommu_fault_type type; > enum iommu_fault_reason reason; > u64 addr; > @@ -340,10 +342,13 @@ struct iommu_fault_event { > * struct iommu_fault_param - per-device IOMMU fault data > * @dev_fault_handler: Callback function to handle IOMMU faults at device level > * @data: handler private data > - * > + * @faults: holds the pending faults which needs response, e.g. page response. > + * @lock: protect pending PRQ event list > */ > struct iommu_fault_param { > iommu_dev_fault_handler_t handler; > + struct list_head faults; > + struct mutex lock; > void *data; > }; > > @@ -357,6 +362,7 @@ struct iommu_fault_param { > * struct iommu_fwspec *iommu_fwspec; > */ > struct iommu_param { > + struct mutex lock; > struct iommu_fault_param *fault_param; > }; > > @@ -456,6 +462,14 @@ 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 *); > @@ -727,6 +741,23 @@ 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; Best regards, Lu Baolu