The iommufd core provides a lookup helper for an IOMMU driver to find a device pointer by device's per-viommu virtual ID. Yet a driver may need an inverted lookup to find a device's per-viommu virtual ID by a device pointer, e.g. when reporting virtual IRQs/events back to the user space. In this case, it'd be unsafe for iommufd core to do an inverted lookup, as the driver can't track the lifecycle of a viommu object or a vdev_id object.
Meanwhile, some HW can even support virtual device ID lookup by its HW- accelerated virtualization feature. E.g. Tegra241 CMDQV HW supports to execute vanilla guest-issued SMMU commands containing virtual Stream ID but requires software to configure a link between virtual Stream ID and physical Stream ID via HW registers. So not only the iommufd core needs a vdev_id lookup table, drivers will want one too.
Given the two justifications above, it's the best practice to provide a a pair of set_vdev_id/unset_vdev_id ops in the viommu ops, so a driver can implement them to control a vdev_id's lifecycle, and configure the HW properly if required.
Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/device.c | 2 ++ drivers/iommu/iommufd/iommufd_private.h | 6 ------ drivers/iommu/iommufd/viommu.c | 23 +++++++++++++++++++---- include/linux/iommufd.h | 13 +++++++++++++ 4 files changed, 34 insertions(+), 10 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 3ad759971b32..01bb5c9f415b 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -145,6 +145,8 @@ void iommufd_device_destroy(struct iommufd_object *obj) old = xa_cmpxchg(&viommu->vdev_ids, vdev_id->id, vdev_id, NULL, GFP_KERNEL); WARN_ON(old != vdev_id); + if (vdev_id->viommu->ops && vdev_id->viommu->ops->unset_vdev_id) + vdev_id->viommu->ops->unset_vdev_id(vdev_id); kfree(vdev_id); idev->vdev_id = NULL; } diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index be1f1813672e..4cb1555991b8 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -621,12 +621,6 @@ struct iommufd_viommu { unsigned int type; };
-struct iommufd_vdev_id { - struct iommufd_viommu *viommu; - struct iommufd_device *idev; - u64 id; -}; - static inline struct iommufd_viommu * iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id) { diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c index 9adc9c62ada9..b1eb900b7fbf 100644 --- a/drivers/iommu/iommufd/viommu.c +++ b/drivers/iommu/iommufd/viommu.c @@ -13,6 +13,8 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
xa_for_each(&viommu->vdev_ids, index, vdev_id) { /* Unlocked since there should be no race in a destroy() */ + if (viommu->ops && viommu->ops->unset_vdev_id) + viommu->ops->unset_vdev_id(vdev_id); vdev_id->idev->vdev_id = NULL; kfree(vdev_id); } @@ -116,10 +118,18 @@ int iommufd_viommu_set_vdev_id(struct iommufd_ucmd *ucmd) goto out_unlock_igroup; }
- vdev_id = kzalloc(sizeof(*vdev_id), GFP_KERNEL); - if (!vdev_id) { - rc = -ENOMEM; - goto out_unlock_igroup; + if (viommu->ops && viommu->ops->set_vdev_id) { + vdev_id = viommu->ops->set_vdev_id(viommu, idev->dev, cmd->vdev_id); + if (IS_ERR(vdev_id)) { + rc = PTR_ERR(vdev_id); + goto out_unlock_igroup; + } + } else { + vdev_id = kzalloc(sizeof(*vdev_id), GFP_KERNEL); + if (!vdev_id) { + rc = -ENOMEM; + goto out_unlock_igroup; + } }
vdev_id->idev = idev; @@ -137,6 +147,8 @@ int iommufd_viommu_set_vdev_id(struct iommufd_ucmd *ucmd) goto out_unlock_igroup;
out_free: + if (viommu->ops && viommu->ops->unset_vdev_id) + viommu->ops->unset_vdev_id(vdev_id); kfree(vdev_id); out_unlock_igroup: mutex_unlock(&idev->igroup->lock); @@ -185,6 +197,9 @@ int iommufd_viommu_unset_vdev_id(struct iommufd_ucmd *ucmd) rc = xa_err(old); goto out_unlock_igroup; } + + if (viommu->ops && viommu->ops->unset_vdev_id) + viommu->ops->unset_vdev_id(old); kfree(old); idev->vdev_id = NULL;
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index f7c265c6de7c..c89583c7c792 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -56,8 +56,18 @@ void iommufd_access_detach(struct iommufd_access *access);
void iommufd_ctx_get(struct iommufd_ctx *ictx);
+struct iommufd_vdev_id { + struct iommufd_viommu *viommu; + struct iommufd_device *idev; + u64 id; +}; + /** * struct iommufd_viommu_ops - viommu specific operations + * @set_vdev_id: Set a virtual device id for a device assigned to a viommu. + * Driver allocates an iommufd_vdev_id and return its pointer. + * @unset_vdev_id: Unset a virtual device id for a device assigned to a viommu. + * iommufd core frees the memory pointed by an iommufd_vdev_id. * @cache_invalidate: Flush hardware cache used by a viommu. It can be used for * any IOMMU hardware specific cache as long as a viommu has * enough information to identify it: for example, a VMID or @@ -69,6 +79,9 @@ void iommufd_ctx_get(struct iommufd_ctx *ictx); * include/uapi/linux/iommufd.h */ struct iommufd_viommu_ops { + struct iommufd_vdev_id *(*set_vdev_id)(struct iommufd_viommu *viommu, + struct device *dev, u64 id); + void (*unset_vdev_id)(struct iommufd_vdev_id *vdev_id); int (*cache_invalidate)(struct iommufd_viommu *viommu, struct iommu_user_data_array *array); };