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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 4FB0FECE560 for ; Mon, 17 Sep 2018 16:56:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0A09214D5 for ; Mon, 17 Sep 2018 16:56:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0A09214D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728787AbeIQWYu (ORCPT ); Mon, 17 Sep 2018 18:24:50 -0400 Received: from mga01.intel.com ([192.55.52.88]:15276 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726795AbeIQWYu (ORCPT ); Mon, 17 Sep 2018 18:24:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Sep 2018 09:56:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,386,1531810800"; d="scan'208";a="73703700" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga007.jf.intel.com with ESMTP; 17 Sep 2018 09:56:37 -0700 Date: Mon, 17 Sep 2018 09:57:58 -0700 From: Jacob Pan To: Auger Eric Cc: iommu@lists.linux-foundation.org, LKML , Joerg Roedel , David Woodhouse , Greg Kroah-Hartman , Alex Williamson , Jean-Philippe Brucker , Raj Ashok , Rafael Wysocki , Jean Delvare , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v5 13/23] iommu: introduce device fault report API Message-ID: <20180917095758.589d44ec@jacob-builder> In-Reply-To: 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> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Sep 2018 15:24:41 +0200 Auger Eric wrote: > Hi Jacob, > > On 5/11/18 10:54 PM, 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); > > + 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); > don't you need to test if (param->fault_param) is set first. Otherwise > you may end up with an unpaired put_device()? You are right, thanks. I am also working on allowing multiple registrations per handler. i.e. device can register the same fault handler with different data. Then I will add refcount. The motivation is that for PCIe device with sub-device partitioned at PASID granularity, fault reporting needs to be at PCI device + PASID level. > > [...] > s/needs/need > taken, thanks > Thanks > > Eric > > + * @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; > > [Jacob Pan]