From: Lu Baolu baolu.lu@linux.intel.com
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 baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com --- drivers/iommu/iommu-priv.h | 2 + drivers/iommu/iommu.c | 82 +++++++++++++++++++++++++++++++------- 2 files changed, 70 insertions(+), 14 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 9d573e971aff..ec213ebd5ecc 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3430,6 +3430,27 @@ 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. @@ -3453,19 +3474,9 @@ 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); + return ret; } EXPORT_SYMBOL_GPL(iommu_attach_device_pasid); @@ -3479,8 +3490,8 @@ 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) { /* Caller must be a probed driver on dev */ struct iommu_group *group = dev->iommu_group; @@ -3492,6 +3503,49 @@ 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; + struct iommu_domain *old_domain; + int ret; + + if (!domain) + return -EINVAL; + + if (!group) + return -ENODEV; + + mutex_lock(&group->mutex); + __iommu_remove_group_pasid(group, pasid); + old_domain = xa_erase(&group->pasid_array, pasid); + ret = __iommu_group_attach_pasid(domain, group, pasid); + if (ret) + goto err_rollback; + mutex_unlock(&group->mutex); + + return 0; + +err_rollback: + if (old_domain) + __iommu_group_attach_pasid(old_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