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 expected to be used only by IOMMUFD.
Co-developed-by: Lu Baolu <[email protected]> Signed-off-by: Lu Baolu <[email protected]> Signed-off-by: Yi Liu <[email protected]> --- drivers/iommu/iommu-priv.h | 3 ++ drivers/iommu/iommu.c | 80 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 79 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index 5f731d994803..0949c02cee93 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -20,6 +20,9 @@ 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, const struct bus_type *bus, diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index b3a1dabed2dd..2d64582b7c43 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3268,14 +3268,15 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group) EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed); static int __iommu_set_group_pasid(struct iommu_domain *domain, - struct iommu_group *group, ioasid_t pasid) + struct iommu_group *group, ioasid_t pasid, + struct iommu_domain *old) { struct group_device *device, *last_gdev; int ret; for_each_group_device(group, device) { ret = domain->ops->set_dev_pasid(domain, device->dev, - pasid, NULL); + pasid, old); if (ret) goto err_revert; } @@ -3289,7 +3290,20 @@ static int __iommu_set_group_pasid(struct iommu_domain *domain, if (device == last_gdev) break; - ops->remove_dev_pasid(device->dev, pasid, domain); + /* If no old domain, undo the succeeded devices/pasid */ + if (!old) { + ops->remove_dev_pasid(device->dev, pasid, domain); + continue; + } + + /* + * Rollback the succeeded devices/pasid to the old domain. + * And it is a driver bug to fail attaching with a previously + * good domain. + */ + if (WARN_ON(old->ops->set_dev_pasid(old, device->dev, + pasid, domain))) + ops->remove_dev_pasid(device->dev, pasid, domain); } return ret; } @@ -3348,7 +3362,7 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, goto out_unlock; } - ret = __iommu_set_group_pasid(domain, group, pasid); + ret = __iommu_set_group_pasid(domain, group, pasid, NULL); if (ret) xa_erase(&group->pasid_array, pasid); out_unlock: @@ -3357,6 +3371,64 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, } EXPORT_SYMBOL_GPL(iommu_attach_device_pasid); +/** + * iommu_replace_device_pasid - Replace the domain that a pasid is attached to + * @domain: the new iommu domain + * @dev: the attached device. + * @pasid: the pasid of the device. + * + * This API allows the pasid to switch domains. Return 0 on success, or an + * error. The pasid will keep the old configuration if replacement failed. + */ +int iommu_replace_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; + void *curr; + int ret; + + if (!domain->ops->set_dev_pasid) + return -EOPNOTSUPP; + + if (!group) + return -ENODEV; + + if (!dev_has_iommu(dev) || dev_iommu_ops(dev) != domain->owner || + pasid == IOMMU_NO_PASID) + return -EINVAL; + + mutex_lock(&group->mutex); + /* + * The recorded domain is inconsistent with the domain pasid is + * actually attached until pasid is attached to the new domain. + * This has race condition with the paths that do not hold + * group->mutex. E.g. the Page Request forwarding. + */ + curr = xa_store(&group->pasid_array, pasid, domain, GFP_KERNEL); + if (!curr) { + xa_erase(&group->pasid_array, pasid); + ret = -EINVAL; + goto out_unlock; + } + + ret = xa_err(curr); + if (ret) + goto out_unlock; + + if (curr == domain) + goto out_unlock; + + ret = __iommu_set_group_pasid(domain, group, pasid, curr); + if (ret) + WARN_ON(domain != xa_store(&group->pasid_array, pasid, + curr, GFP_KERNEL)); +out_unlock: + mutex_unlock(&group->mutex); + return ret; +} +EXPORT_SYMBOL_NS_GPL(iommu_replace_device_pasid, IOMMUFD_INTERNAL); + /* * iommu_detach_device_pasid() - Detach the domain from pasid of device * @domain: the iommu domain. -- 2.34.1
