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From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	"David Woodhouse" <dwmw2@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc: "Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	Jean Delvare <khali@linux-fr.org>,
	Christoph Hellwig <hch@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>
Subject: RE: [PATCH v5 13/23] iommu: introduce device fault report API
Date: Thu, 17 May 2018 11:41:56 +0000	[thread overview]
Message-ID: <A2975661238FB949B60364EF0F2C257439BF2537@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <1526072055-86990-14-git-send-email-jacob.jun.pan@linux.intel.com>

> From: Jacob Pan [mailto:jacob.jun.pan@linux.intel.com]
> Sent: Saturday, May 12, 2018 4:54 AM
> 
> 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 <jacob.jun.pan@linux.intel.com>
> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> ---
>  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(&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(struct iommu_fault_param), GFP_KERNEL);
> +	if (!param->fault_param) {
> +		put_device(dev);
> +		ret = -ENOMEM;
> +		goto done_unlock;
> +	}
> +	mutex_init(&param->fault_param->lock);
> +	param->fault_param->handler = handler;
> +	param->fault_param->data = data;
> +	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);
> +	/* 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
> + * @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);

I may missed it. Here only see list add, how about removing? Who would remove
entry from the fault list?

> +		mutex_unlock(&fparam->lock);
> +	}
> +	ret = fparam->handler(evt, fparam->data);

I remember you mentioned there will be a queue to store the faults. Is it in the
fparam->faults list? Or there is no such queue?

Thanks,
Yi Liu

> +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;
> --
> 2.7.4

  parent reply	other threads:[~2018-05-17 11:41 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-11 20:53 [PATCH v5 00/23] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan
2018-05-11 20:53 ` [PATCH v5 01/23] iommu: introduce bind_pasid_table API function Jacob Pan
2018-08-23 16:34   ` Auger Eric
2018-08-24 12:47     ` Liu, Yi L
2018-08-24 13:20       ` Auger Eric
2018-08-28 17:04         ` Jacob Pan
2018-08-24 15:00   ` Auger Eric
2018-08-28  5:14     ` Jacob Pan
2018-08-28  8:34       ` Auger Eric
2018-08-28 16:36         ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 02/23] iommu/vt-d: move device_domain_info to header Jacob Pan
2018-05-11 20:53 ` [PATCH v5 03/23] iommu/vt-d: add a flag for pasid table bound status Jacob Pan
2018-05-13  7:33   ` Lu Baolu
2018-05-14 18:51     ` Jacob Pan
2018-05-13  8:01   ` Lu Baolu
2018-05-14 18:52     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 04/23] iommu/vt-d: add bind_pasid_table function Jacob Pan
2018-05-13  9:29   ` Lu Baolu
2018-05-14 20:22     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 05/23] iommu: introduce iommu invalidate API function Jacob Pan
2018-05-11 20:53 ` [PATCH v5 06/23] iommu/vt-d: add definitions for PFSID Jacob Pan
2018-05-14  1:36   ` Lu Baolu
2018-05-14 20:30     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 07/23] iommu/vt-d: fix dev iotlb pfsid use Jacob Pan
2018-05-14  1:52   ` Lu Baolu
2018-05-14 20:38     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 08/23] iommu/vt-d: support flushing more translation cache types Jacob Pan
2018-05-14  2:18   ` Lu Baolu
2018-05-14 20:46     ` Jacob Pan
2018-05-17  8:44   ` kbuild test robot
2018-05-11 20:54 ` [PATCH v5 09/23] iommu/vt-d: add svm/sva invalidate function Jacob Pan
2018-05-14  3:35   ` Lu Baolu
2018-05-14 20:49     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 10/23] iommu: introduce device fault data Jacob Pan
2018-09-21 10:07   ` Auger Eric
2018-09-21 17:05     ` Jacob Pan
2018-09-26 10:20       ` Auger Eric
2018-05-11 20:54 ` [PATCH v5 11/23] driver core: add per device iommu param Jacob Pan
2018-05-14  5:27   ` Lu Baolu
2018-05-14 20:52     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 12/23] iommu: add a timeout parameter for prq response Jacob Pan
2018-05-11 20:54 ` [PATCH v5 13/23] iommu: introduce device fault report API Jacob Pan
2018-05-14  6:01   ` Lu Baolu
2018-05-14 20:55     ` Jacob Pan
2018-05-15  6:52       ` Lu Baolu
2018-05-17 11:41   ` Liu, Yi L [this message]
2018-05-17 15:59     ` Jacob Pan
2018-05-17 23:22       ` Liu, Yi L
2018-05-21 23:03         ` Jacob Pan
2018-09-06  9:25   ` Auger Eric
2018-09-06 12:42     ` Jean-Philippe Brucker
2018-09-06 13:14       ` Auger Eric
2018-09-06 17:06         ` Jean-Philippe Brucker
2018-09-07  7:11           ` Auger Eric
2018-09-07 11:23             ` Jean-Philippe Brucker
2018-09-14 13:24   ` Auger Eric
2018-09-17 16:57     ` Jacob Pan
2018-09-25 14:58   ` Jean-Philippe Brucker
2018-09-25 22:17     ` Jacob Pan
2018-09-26 10:14       ` Jean-Philippe Brucker
2018-05-11 20:54 ` [PATCH v5 14/23] iommu: introduce page response function Jacob Pan
2018-05-14  6:39   ` Lu Baolu
2018-05-29 16:13     ` Jacob Pan
2018-09-10 14:52   ` Auger Eric
2018-09-10 17:50     ` Jacob Pan
2018-09-10 19:06       ` Auger Eric
2018-05-11 20:54 ` [PATCH v5 15/23] iommu: handle page response timeout Jacob Pan
2018-05-14  7:43   ` Lu Baolu
2018-05-29 16:20     ` Jacob Pan
2018-05-30  7:46       ` Lu Baolu
2018-05-11 20:54 ` [PATCH v5 16/23] iommu/config: add build dependency for dmar Jacob Pan
2018-05-11 20:54 ` [PATCH v5 17/23] iommu/vt-d: report non-recoverable faults to device Jacob Pan
2018-05-14  8:17   ` Lu Baolu
2018-05-29 17:33     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 18/23] iommu/intel-svm: report device page request Jacob Pan
2018-05-11 20:54 ` [PATCH v5 19/23] iommu/intel-svm: replace dev ops with fault report API Jacob Pan
2018-05-11 20:54 ` [PATCH v5 20/23] iommu/intel-svm: do not flush iotlb for viommu Jacob Pan
2018-05-11 20:54 ` [PATCH v5 21/23] iommu/vt-d: add intel iommu page response function Jacob Pan
2018-05-11 20:54 ` [PATCH v5 22/23] trace/iommu: add sva trace events Jacob Pan
2018-05-11 20:54 ` [PATCH v5 23/23] iommu: use sva invalidate and device fault trace event Jacob Pan
2018-05-29 15:54 ` [PATCH v5 00/23] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan

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