diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 66659e5d1ec2..2515786d4156 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -62,14 +62,14 @@ struct iommu_group { int id; struct iommu_domain *default_domain; struct iommu_domain *blocking_domain; - /* - * During a group device reset, @resetting_domain points to the physical - * domain, while @domain points to the attached domain before the reset. - */ - struct iommu_domain *resetting_domain; struct iommu_domain *domain; struct list_head entry; unsigned int owner_cnt; + /* + * Number of devices in the group undergoing or awaiting recovery. + * If non-zero, concurrent domain attachments are rejected. + */ + unsigned int recovery_cnt; void *owner; }; @@ -77,12 +77,32 @@ struct group_device { struct list_head list; struct device *dev; char *name; + /* + * Device is blocked for a pending recovery while its group->domain is + * retained. This can happen when: + * - Device is undergoing a reset + */ + bool blocked; }; /* Iterate over each struct group_device in a struct iommu_group */ #define for_each_group_device(group, pos) \ list_for_each_entry(pos, &(group)->devices, list) +static struct group_device *__dev_to_gdev(struct device *dev) +{ + struct iommu_group *group = dev->iommu_group; + struct group_device *gdev; + + lockdep_assert_held(&group->mutex); + + for_each_group_device(group, gdev) { + if (gdev->dev == dev) + return gdev; + } + return NULL; +} + struct iommu_group_attribute { struct attribute attr; ssize_t (*show)(struct iommu_group *group, char *buf); @@ -2196,6 +2216,8 @@ EXPORT_SYMBOL_GPL(iommu_attach_device); int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain) { + struct group_device *gdev; + /* * This is called on the dma mapping fast path so avoid locking. This is * racy, but we have an expectation that the driver will setup its DMAs @@ -2206,14 +2228,18 @@ int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain) guard(mutex)(&dev->iommu_group->mutex); + gdev = __dev_to_gdev(dev); + if (WARN_ON(!gdev)) + return -ENODEV; + /* - * This is a concurrent attach during a device reset. Reject it until + * This is a concurrent attach during device recovery. Reject it until * pci_dev_reset_iommu_done() attaches the device to group->domain. * * Note that this might fail the iommu_dma_map(). But there's nothing * more we can do here. */ - if (dev->iommu_group->resetting_domain) + if (gdev->blocked) return -EBUSY; return __iommu_attach_device(domain, dev, NULL); } @@ -2270,19 +2296,24 @@ EXPORT_SYMBOL_GPL(iommu_get_domain_for_dev); struct iommu_domain *iommu_driver_get_domain_for_dev(struct device *dev) { struct iommu_group *group = dev->iommu_group; + struct group_device *gdev; lockdep_assert_held(&group->mutex); + gdev = __dev_to_gdev(dev); + if (WARN_ON(!gdev)) + return NULL; + /* * Driver handles the low-level __iommu_attach_device(), including the * one invoked by pci_dev_reset_iommu_done() re-attaching the device to * the cached group->domain. In this case, the driver must get the old - * domain from group->resetting_domain rather than group->domain. This + * domain from group->blocking_domain rather than group->domain. This * prevents it from re-attaching the device from group->domain (old) to * group->domain (new). */ - if (group->resetting_domain) - return group->resetting_domain; + if (gdev->blocked) + return group->blocking_domain; return group->domain; } @@ -2441,10 +2472,10 @@ static int __iommu_group_set_domain_internal(struct iommu_group *group, return -EINVAL; /* - * This is a concurrent attach during a device reset. Reject it until + * This is a concurrent attach during device recovery. Reject it until * pci_dev_reset_iommu_done() attaches the device to group->domain. */ - if (group->resetting_domain) + if (group->recovery_cnt) return -EBUSY; /* @@ -3615,10 +3646,10 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, mutex_lock(&group->mutex); /* - * This is a concurrent attach during a device reset. Reject it until + * This is a concurrent attach during device recovery. Reject it until * pci_dev_reset_iommu_done() attaches the device to group->domain. */ - if (group->resetting_domain) { + if (group->recovery_cnt) { ret = -EBUSY; goto out_unlock; } @@ -3708,10 +3739,10 @@ int iommu_replace_device_pasid(struct iommu_domain *domain, mutex_lock(&group->mutex); /* - * This is a concurrent attach during a device reset. Reject it until + * This is a concurrent attach during device recovery. Reject it until * pci_dev_reset_iommu_done() attaches the device to group->domain. */ - if (group->resetting_domain) { + if (group->recovery_cnt) { ret = -EBUSY; goto out_unlock; } @@ -3982,12 +4013,12 @@ EXPORT_SYMBOL_NS_GPL(iommu_replace_group_handle, "IOMMUFD_INTERNAL"); * routine wants to block any IOMMU activity: translation and ATS invalidation. * * This function attaches the device's RID/PASID(s) the group->blocking_domain, - * setting the group->resetting_domain. This allows the IOMMU driver pausing any + * incrementing the group->recovery_cnt, to allow the IOMMU driver pausing any * IOMMU activity while leaving the group->domain pointer intact. Later when the * reset is finished, pci_dev_reset_iommu_done() can restore everything. * * Caller must use pci_dev_reset_iommu_prepare() with pci_dev_reset_iommu_done() - * before/after the core-level reset routine, to unset the resetting_domain. + * before/after the core-level reset routine, to decrement the recovery_cnt. * * Return: 0 on success or negative error code if the preparation failed. * @@ -4000,6 +4031,7 @@ EXPORT_SYMBOL_NS_GPL(iommu_replace_group_handle, "IOMMUFD_INTERNAL"); int pci_dev_reset_iommu_prepare(struct pci_dev *pdev) { struct iommu_group *group = pdev->dev.iommu_group; + struct group_device *gdev; unsigned long pasid; void *entry; int ret; @@ -4009,8 +4041,12 @@ int pci_dev_reset_iommu_prepare(struct pci_dev *pdev) guard(mutex)(&group->mutex); + gdev = __dev_to_gdev(&pdev->dev); + if (WARN_ON(!gdev)) + return -ENODEV; + /* Re-entry is not allowed */ - if (WARN_ON(group->resetting_domain)) + if (WARN_ON(gdev->blocked)) return -EBUSY; ret = __iommu_group_alloc_blocking_domain(group); @@ -4025,6 +4061,13 @@ int pci_dev_reset_iommu_prepare(struct pci_dev *pdev) return ret; } + /* + * Update gdev->blocked upon the domain change, as it is used to return + * the correct domain in iommu_driver_get_domain_for_dev() that might be + * called in a set_dev_pasid callback function. + */ + gdev->blocked = true; + /* * Stage PASID domains at blocking_domain while retaining pasid_array. * @@ -4035,7 +4078,7 @@ int pci_dev_reset_iommu_prepare(struct pci_dev *pdev) iommu_remove_dev_pasid(&pdev->dev, pasid, pasid_array_entry_to_domain(entry)); - group->resetting_domain = group->blocking_domain; + group->recovery_cnt++; return ret; } EXPORT_SYMBOL_GPL(pci_dev_reset_iommu_prepare); @@ -4057,6 +4100,7 @@ EXPORT_SYMBOL_GPL(pci_dev_reset_iommu_prepare); void pci_dev_reset_iommu_done(struct pci_dev *pdev) { struct iommu_group *group = pdev->dev.iommu_group; + struct group_device *gdev; unsigned long pasid; void *entry; @@ -4065,11 +4109,13 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev) guard(mutex)(&group->mutex); - /* pci_dev_reset_iommu_prepare() was bypassed for the device */ - if (!group->resetting_domain) + gdev = __dev_to_gdev(&pdev->dev); + if (WARN_ON(!gdev)) + return; + + if (!gdev->blocked) return; - /* pci_dev_reset_iommu_prepare() was not successfully called */ if (WARN_ON(!group->blocking_domain)) return; @@ -4084,6 +4130,13 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev) group->blocking_domain)); } + /* + * Update gdev->blocked upon the domain change, as it is used to return + * the correct domain in iommu_driver_get_domain_for_dev() that might be + * called in a set_dev_pasid callback function. + */ + gdev->blocked = false; + /* * Re-attach PASID domains back to the domains retained in pasid_array. * @@ -4095,7 +4148,8 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev) pasid_array_entry_to_domain(entry), group, pasid, group->blocking_domain)); - group->resetting_domain = NULL; + if (!WARN_ON(group->recovery_cnt == 0)) + group->recovery_cnt--; } EXPORT_SYMBOL_GPL(pci_dev_reset_iommu_done);