From: Lu Baolu <[email protected]> Provide a high-level API to allow replacements of one domain with another for specific pasid of a device. This is similar to iommu_group_replace_domain() and it is also expected to be used only by IOMMUFD.
Signed-off-by: Lu Baolu <[email protected]> Signed-off-by: Yi Liu <[email protected]> --- drivers/iommu/iommu-priv.h | 2 ++ drivers/iommu/iommu.c | 73 ++++++++++++++++++++++++++++++-------- 2 files changed, 60 insertions(+), 15 deletions(-) diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index 2024a2313348..5c32637f6325 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -19,6 +19,8 @@ static inline const struct iommu_ops *dev_iommu_ops(struct device *dev) int iommu_group_replace_domain(struct iommu_group *group, struct iommu_domain *new_domain); +int iommu_replace_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid); int iommu_device_register_bus(struct iommu_device *iommu, const struct iommu_ops *ops, struct bus_type *bus, diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index e53c9e659ae6..b47581c7b1c6 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3382,6 +3382,27 @@ static void __iommu_remove_group_pasid(struct iommu_group *group, } } +static int __iommu_group_attach_pasid(struct iommu_domain *domain, + struct iommu_group *group, ioasid_t pasid) +{ + void *curr; + int ret; + + lockdep_assert_held(&group->mutex); + + curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain, GFP_KERNEL); + if (curr) + return xa_err(curr) ? : -EBUSY; + + ret = __iommu_set_group_pasid(domain, group, pasid); + if (ret) { + __iommu_remove_group_pasid(group, pasid); + xa_erase(&group->pasid_array, pasid); + } + + return ret; +} + /* * iommu_attach_device_pasid() - Attach a domain to pasid of device * @domain: the iommu domain. @@ -3394,7 +3415,6 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid) { struct iommu_group *group; - void *curr; int ret; if (!domain->ops->set_dev_pasid) @@ -3405,19 +3425,9 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, return -ENODEV; mutex_lock(&group->mutex); - curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain, GFP_KERNEL); - if (curr) { - ret = xa_err(curr) ? : -EBUSY; - goto out_unlock; - } - - ret = __iommu_set_group_pasid(domain, group, pasid); - if (ret) { - __iommu_remove_group_pasid(group, pasid); - xa_erase(&group->pasid_array, pasid); - } -out_unlock: + ret = __iommu_group_attach_pasid(domain, group, pasid); mutex_unlock(&group->mutex); + iommu_group_put(group); return ret; @@ -3433,8 +3443,8 @@ EXPORT_SYMBOL_GPL(iommu_attach_device_pasid); * The @domain must have been attached to @pasid of the @dev with * iommu_attach_device_pasid(). */ -void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev, - ioasid_t pasid) +void iommu_detach_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid) { struct iommu_group *group = iommu_group_get(dev); @@ -3447,6 +3457,39 @@ void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev, } EXPORT_SYMBOL_GPL(iommu_detach_device_pasid); +/** + * iommu_replace_device_pasid - replace the domain that a pasid is attached to + * @domain: new IOMMU domain to replace with + * @dev: the physical device + * @pasid: pasid that will be attached to the new domain + * + * This API allows the pasid to switch domains. Return 0 on success, or an + * error. The pasid will roll back to use the old domain if failure. The + * caller could call iommu_detach_device_pasid() before free the old domain + * in order to avoid use-after-free case. + */ +int iommu_replace_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid) +{ + struct iommu_group *group = dev->iommu_group; + int ret; + + if (!domain) + return -EINVAL; + + if (!group) + return -ENODEV; + + mutex_lock(&group->mutex); + __iommu_remove_group_pasid(group, pasid); + xa_erase(&group->pasid_array, pasid); + ret = __iommu_group_attach_pasid(domain, group, pasid); + mutex_unlock(&group->mutex); + + return ret; +} +EXPORT_SYMBOL_NS_GPL(iommu_replace_device_pasid, IOMMUFD_INTERNAL); + /* * iommu_get_domain_for_dev_pasid() - Retrieve domain for @pasid of @dev * @dev: the queried device -- 2.34.1
