Convert iopf_queue_remove_device() to return void instead of an error code, as the return value is never used. This removal helper is designed to be never-failed, so there's no need for error handling. Ack all outstanding page requests from the device with the response code of IOMMU_PAGE_RESP_INVALID, indicating device should not attempt any retry. Add comments to this helper explaining the steps involved in removing a device from the iopf queue and disabling its PRI. Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> Tested-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> --- include/linux/iommu.h | 5 ++-- drivers/iommu/intel/iommu.c | 7 +---- drivers/iommu/io-pgfault.c | 59 ++++++++++++++++++++++++------------- 3 files changed, 41 insertions(+), 30 deletions(-) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index c2416aa79922..d8d173309469 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -1465,7 +1465,7 @@ iommu_sva_domain_alloc(struct device *dev, struct mm_struct *mm) #ifdef CONFIG_IOMMU_IOPF int iopf_queue_add_device(struct iopf_queue *queue, struct device *dev); -int iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev); +void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev); int iopf_queue_flush_dev(struct device *dev); struct iopf_queue *iopf_queue_alloc(const char *name); void iopf_queue_free(struct iopf_queue *queue); @@ -1481,10 +1481,9 @@ iopf_queue_add_device(struct iopf_queue *queue, struct device *dev) return -ENODEV; } -static inline int +static inline void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) { - return -ENODEV; } static inline int iopf_queue_flush_dev(struct device *dev) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 29a12f289e2e..a81a2be9b870 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4455,12 +4455,7 @@ static int intel_iommu_disable_iopf(struct device *dev) */ pci_disable_pri(to_pci_dev(dev)); info->pri_enabled = 0; - - /* - * With PRI disabled and outstanding PRQs drained, removing device - * from iopf queue should never fail. - */ - WARN_ON(iopf_queue_remove_device(iommu->iopf_queue, dev)); + iopf_queue_remove_device(iommu->iopf_queue, dev); return 0; } diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c index 3a907bad2fcb..3221f6387beb 100644 --- a/drivers/iommu/io-pgfault.c +++ b/drivers/iommu/io-pgfault.c @@ -449,42 +449,61 @@ EXPORT_SYMBOL_GPL(iopf_queue_add_device); * @queue: IOPF queue * @dev: device to remove * - * Caller makes sure that no more faults are reported for this device. + * Removing a device from an iopf_queue. It's recommended to follow these + * steps when removing a device: * - * Return: 0 on success and <0 on error. + * - Disable new PRI reception: Turn off PRI generation in the IOMMU hardware + * and flush any hardware page request queues. This should be done before + * calling into this helper. + * - Acknowledge all outstanding PRQs to the device: Respond to all outstanding + * page requests with IOMMU_PAGE_RESP_INVALID, indicating the device should + * not retry. This helper function handles this. + * - Disable PRI on the device: After calling this helper, the caller could + * then disable PRI on the device. + * - Tear down the iopf infrastructure: Calling iopf_queue_remove_device() + * essentially disassociates the device. The fault_param might still exist, + * but iommu_page_response() will do nothing. The device fault parameter + * reference count has been properly passed from iommu_report_device_fault() + * to the fault handling work, and will eventually be released after + * iommu_page_response(). */ -int iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) +void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) { - int ret = 0; struct iopf_fault *iopf, *next; + struct iommu_page_response resp; struct dev_iommu *param = dev->iommu; struct iommu_fault_param *fault_param; + const struct iommu_ops *ops = dev_iommu_ops(dev); mutex_lock(&queue->lock); mutex_lock(¶m->lock); fault_param = rcu_dereference_check(param->fault_param, lockdep_is_held(¶m->lock)); - if (!fault_param) { - ret = -ENODEV; - goto unlock; - } - - if (fault_param->queue != queue) { - ret = -EINVAL; - goto unlock; - } - if (!list_empty(&fault_param->faults)) { - ret = -EBUSY; + if (WARN_ON(!fault_param || fault_param->queue != queue)) goto unlock; - } - - list_del(&fault_param->queue_list); - /* Just in case some faults are still stuck */ + mutex_lock(&fault_param->lock); list_for_each_entry_safe(iopf, next, &fault_param->partial, list) kfree(iopf); + list_for_each_entry_safe(iopf, next, &fault_param->faults, list) { + memset(&resp, 0, sizeof(struct iommu_page_response)); + resp.pasid = iopf->fault.prm.pasid; + resp.grpid = iopf->fault.prm.grpid; + resp.code = IOMMU_PAGE_RESP_INVALID; + + if (iopf->fault.prm.flags & IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID) + resp.flags = IOMMU_PAGE_RESP_PASID_VALID; + + ops->page_response(dev, iopf, &resp); + list_del(&iopf->list); + kfree(iopf); + } + mutex_unlock(&fault_param->lock); + + list_del(&fault_param->queue_list); + /* dec the ref owned by iopf_queue_add_device() */ rcu_assign_pointer(param->fault_param, NULL); if (refcount_dec_and_test(&fault_param->users)) @@ -492,8 +511,6 @@ int iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev) unlock: mutex_unlock(¶m->lock); mutex_unlock(&queue->lock); - - return ret; } EXPORT_SYMBOL_GPL(iopf_queue_remove_device); -- 2.34.1