Messages in this thread | | | Date | Tue, 18 Jun 2019 16:41:58 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH v4 03/22] iommu: Introduce device fault report API |
| |
On Sun, 9 Jun 2019 06:44:03 -0700 Jacob Pan <jacob.jun.pan@linux.intel.com> 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. > > 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 <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> > Signed-off-by: Eric Auger <eric.auger@redhat.com>
A few nitpicks and minor suggestions inline.
> --- > drivers/iommu/iommu.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++- > include/linux/iommu.h | 33 ++++++++++++- > 2 files changed, 157 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 67ee662..7955184 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 +681,7 @@ 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: > @@ -720,7 +728,7 @@ 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; > @@ -855,6 +863,123 @@ 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. > + * > + * 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); > +
One blank line probably enough.. (my personal favourite stylistic nitpick ;)
> + > +/** > + * iommu_report_device_fault() - Report fault event to device > + * @dev: the device > + * @evt: fault event data > + * > + * Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ > + * handler.
What constraints does that put on it? We probably don't care about the fact it is in a threaded irq as such, rather something that is true as a result of that?
> + * > + * 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 7890a92..b87b74c 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -322,9 +322,9 @@ 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 > * > + * @handler: Callback function to handle IOMMU faults at device level
This should be in the previous patch, not this one.
> + * @data: handler private data > */ > struct iommu_fault_param { > iommu_dev_fault_handler_t handler; > @@ -341,6 +341,7 @@ struct iommu_fault_param { > * struct iommu_fwspec *iommu_fwspec; > */ > struct iommu_param { > + struct mutex lock;
Structure has kernel doc so this should be added to that.
> struct iommu_fault_param *fault_param; > }; > > @@ -433,6 +434,15 @@ 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 *); > @@ -741,6 +751,25 @@ 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;
| |