diff options
| -rw-r--r-- | drivers/iommu/iommu.c | 127 |
1 files changed, 91 insertions, 36 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 0c42ece25854..0b22e51e90f4 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -44,6 +44,7 @@ struct iommu_group { char *name; int id; struct iommu_domain *default_domain; + struct iommu_domain *blocking_domain; struct iommu_domain *domain; struct list_head entry; unsigned int owner_cnt; @@ -82,8 +83,8 @@ static int __iommu_attach_device(struct iommu_domain *domain, struct device *dev); static int __iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group); -static void __iommu_detach_group(struct iommu_domain *domain, - struct iommu_group *group); +static int __iommu_group_set_domain(struct iommu_group *group, + struct iommu_domain *new_domain); static int iommu_create_device_direct_mappings(struct iommu_group *group, struct device *dev); static struct iommu_group *iommu_group_get_for_dev(struct device *dev); @@ -596,6 +597,8 @@ static void iommu_group_release(struct kobject *kobj) if (group->default_domain) iommu_domain_free(group->default_domain); + if (group->blocking_domain) + iommu_domain_free(group->blocking_domain); kfree(group->name); kfree(group); @@ -1907,6 +1910,24 @@ void iommu_domain_free(struct iommu_domain *domain) } EXPORT_SYMBOL_GPL(iommu_domain_free); +/* + * Put the group's domain back to the appropriate core-owned domain - either the + * standard kernel-mode DMA configuration or an all-DMA-blocked domain. + */ +static void __iommu_group_set_core_domain(struct iommu_group *group) +{ + struct iommu_domain *new_domain; + int ret; + + if (group->owner) + new_domain = group->blocking_domain; + else + new_domain = group->default_domain; + + ret = __iommu_group_set_domain(group, new_domain); + WARN(ret, "iommu driver failed to attach the default/blocking domain"); +} + static int __iommu_attach_device(struct iommu_domain *domain, struct device *dev) { @@ -1963,9 +1984,6 @@ static void __iommu_detach_device(struct iommu_domain *domain, if (iommu_is_attach_deferred(dev)) return; - if (unlikely(domain->ops->detach_dev == NULL)) - return; - domain->ops->detach_dev(domain, dev); trace_detach_device_from_domain(dev); } @@ -1979,12 +1997,10 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev) return; mutex_lock(&group->mutex); - if (iommu_group_device_count(group) != 1) { - WARN_ON(1); + if (WARN_ON(domain != group->domain) || + WARN_ON(iommu_group_device_count(group) != 1)) goto out_unlock; - } - - __iommu_detach_group(domain, group); + __iommu_group_set_core_domain(group); out_unlock: mutex_unlock(&group->mutex); @@ -2040,7 +2056,8 @@ static int __iommu_attach_group(struct iommu_domain *domain, { int ret; - if (group->domain && group->domain != group->default_domain) + if (group->domain && group->domain != group->default_domain && + group->domain != group->blocking_domain) return -EBUSY; ret = __iommu_group_for_each_dev(group, domain, @@ -2072,38 +2089,49 @@ static int iommu_group_do_detach_device(struct device *dev, void *data) return 0; } -static void __iommu_detach_group(struct iommu_domain *domain, - struct iommu_group *group) +static int __iommu_group_set_domain(struct iommu_group *group, + struct iommu_domain *new_domain) { int ret; + if (group->domain == new_domain) + return 0; + /* - * If the group has been claimed already, do not re-attach the default - * domain. + * New drivers should support default domains and so the detach_dev() op + * will never be called. Otherwise the NULL domain represents some + * platform specific behavior. */ - if (!group->default_domain || group->owner) { - __iommu_group_for_each_dev(group, domain, + if (!new_domain) { + if (WARN_ON(!group->domain->ops->detach_dev)) + return -EINVAL; + __iommu_group_for_each_dev(group, group->domain, iommu_group_do_detach_device); group->domain = NULL; - return; + return 0; } - if (group->domain == group->default_domain) - return; - - /* Detach by re-attaching to the default domain */ - ret = __iommu_group_for_each_dev(group, group->default_domain, + /* + * Changing the domain is done by calling attach_dev() on the new + * domain. This switch does not have to be atomic and DMA can be + * discarded during the transition. DMA must only be able to access + * either new_domain or group->domain, never something else. + * + * Note that this is called in error unwind paths, attaching to a + * domain that has already been attached cannot fail. + */ + ret = __iommu_group_for_each_dev(group, new_domain, iommu_group_do_attach_device); - if (ret != 0) - WARN_ON(1); - else - group->domain = group->default_domain; + if (ret) + return ret; + group->domain = new_domain; + return 0; } void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group) { mutex_lock(&group->mutex); - __iommu_detach_group(domain, group); + __iommu_group_set_core_domain(group); mutex_unlock(&group->mutex); } EXPORT_SYMBOL_GPL(iommu_detach_group); @@ -3088,6 +3116,29 @@ void iommu_device_unuse_default_domain(struct device *dev) iommu_group_put(group); } +static int __iommu_group_alloc_blocking_domain(struct iommu_group *group) +{ + struct group_device *dev = + list_first_entry(&group->devices, struct group_device, list); + + if (group->blocking_domain) + return 0; + + group->blocking_domain = + __iommu_domain_alloc(dev->dev->bus, IOMMU_DOMAIN_BLOCKED); + if (!group->blocking_domain) { + /* + * For drivers that do not yet understand IOMMU_DOMAIN_BLOCKED + * create an empty domain instead. + */ + group->blocking_domain = __iommu_domain_alloc( + dev->dev->bus, IOMMU_DOMAIN_UNMANAGED); + if (!group->blocking_domain) + return -EINVAL; + } + return 0; +} + /** * iommu_group_claim_dma_owner() - Set DMA ownership of a group * @group: The group. @@ -3111,9 +3162,14 @@ int iommu_group_claim_dma_owner(struct iommu_group *group, void *owner) goto unlock_out; } + ret = __iommu_group_alloc_blocking_domain(group); + if (ret) + goto unlock_out; + + ret = __iommu_group_set_domain(group, group->blocking_domain); + if (ret) + goto unlock_out; group->owner = owner; - if (group->domain) - __iommu_detach_group(group->domain, group); } group->owner_cnt++; @@ -3132,18 +3188,17 @@ EXPORT_SYMBOL_GPL(iommu_group_claim_dma_owner); */ void iommu_group_release_dma_owner(struct iommu_group *group) { + int ret; + mutex_lock(&group->mutex); if (WARN_ON(!group->owner_cnt || !group->owner)) goto unlock_out; group->owner_cnt = 0; - /* - * The UNMANAGED domain should be detached before all USER - * owners have been released. - */ - if (!WARN_ON(group->domain) && group->default_domain) - __iommu_attach_group(group->default_domain, group); group->owner = NULL; + ret = __iommu_group_set_domain(group, group->default_domain); + WARN(ret, "iommu driver failed to attach the default domain"); + unlock_out: mutex_unlock(&group->mutex); } |