NVIDIA VCMDQ driver will have a driver-defined vDEVICE structure and do some HW configurations with that.
To allow IOMMU drivers to define their own vDEVICE structures, move the struct iommufd_vdevice to the public header and provide a pair of viommu ops, similar to get_viommu_size and viommu_init.
Doing this, however, creates a new window between the vDEVICE allocation and its driver-level initialization, during which an abort could happen but it can't invoke a driver destroy function from the struct viommu_ops since the driver structure isn't initialized yet. vIOMMU object doesn't have this problem, since its destroy op is set via the viommu_ops by the driver viommu_init function. Thus, vDEVICE should do something similar: add a destroy function pointer inside the struct iommufd_vdevice instead of the struct iommufd_viommu_ops.
Note that there is unlikely a use case for a type dependent vDEVICE, so a static vdevice_size is probably enough for the near term instead of a get_vdevice_size function op.
Reviewed-by: Jason Gunthorpe jgg@nvidia.com Reviewed-by: Kevin Tian kevin.tian@intel.com Reviewed-by: Pranjal Shrivastava praan@google.com Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/iommufd_private.h | 12 ---------- include/linux/iommufd.h | 31 +++++++++++++++++++++++++ drivers/iommu/iommufd/viommu.c | 26 ++++++++++++++++++++- 3 files changed, 56 insertions(+), 13 deletions(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index b849099e804b..4db8c6890f4c 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -653,18 +653,6 @@ void iommufd_viommu_destroy(struct iommufd_object *obj); int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd); void iommufd_vdevice_destroy(struct iommufd_object *obj);
-struct iommufd_vdevice { - struct iommufd_object obj; - struct iommufd_viommu *viommu; - struct device *dev; - - /* - * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of - * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table - */ - u64 virt_id; -}; - #ifdef CONFIG_IOMMUFD_TEST int iommufd_test(struct iommufd_ucmd *ucmd); void iommufd_selftest_destroy(struct iommufd_object *obj); diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index 2d1bf2f97ee3..3709b264af28 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -104,6 +104,21 @@ struct iommufd_viommu { enum iommu_viommu_type type; };
+struct iommufd_vdevice { + struct iommufd_object obj; + struct iommufd_viommu *viommu; + struct device *dev; + + /* + * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of + * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table + */ + u64 virt_id; + + /* Clean up all driver-specific parts of an iommufd_vdevice */ + void (*destroy)(struct iommufd_vdevice *vdev); +}; + /** * struct iommufd_viommu_ops - vIOMMU specific operations * @destroy: Clean up all driver-specific parts of an iommufd_viommu. The memory @@ -120,6 +135,14 @@ struct iommufd_viommu { * array->entry_num to report the number of handled requests. * The data structure of the array entry must be defined in * include/uapi/linux/iommufd.h + * @vdevice_size: Size of the driver-defined vDEVICE structure per this vIOMMU + * @vdevice_init: Initialize the driver-level structure of a vDEVICE object, or + * related HW procedure. @vdev is already initialized by iommufd + * core: vdev->dev and vdev->viommu pointers; vdev->id carries a + * per-vIOMMU virtual ID (refer to struct iommu_vdevice_alloc in + * include/uapi/linux/iommufd.h) + * If driver has a deinit function to revert what vdevice_init op + * does, it should set it to the @vdev->destroy function pointer */ struct iommufd_viommu_ops { void (*destroy)(struct iommufd_viommu *viommu); @@ -128,6 +151,8 @@ struct iommufd_viommu_ops { const struct iommu_user_data *user_data); int (*cache_invalidate)(struct iommufd_viommu *viommu, struct iommu_user_data_array *array); + const size_t vdevice_size; + int (*vdevice_init)(struct iommufd_vdevice *vdev); };
#if IS_ENABLED(CONFIG_IOMMUFD) @@ -224,4 +249,10 @@ static inline int iommufd_viommu_report_event(struct iommufd_viommu *viommu, BUILD_BUG_ON_ZERO(offsetof(drv_struct, member)) + \ BUILD_BUG_ON_ZERO(!__same_type(struct iommufd_viommu, \ ((drv_struct *)NULL)->member))) + +#define VDEVICE_STRUCT_SIZE(drv_struct, member) \ + (sizeof(drv_struct) + \ + BUILD_BUG_ON_ZERO(offsetof(drv_struct, member)) + \ + BUILD_BUG_ON_ZERO(!__same_type(struct iommufd_vdevice, \ + ((drv_struct *)NULL)->member))) #endif diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c index c0365849f849..081ee6697a11 100644 --- a/drivers/iommu/iommufd/viommu.c +++ b/drivers/iommu/iommufd/viommu.c @@ -116,6 +116,8 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj) container_of(obj, struct iommufd_vdevice, obj); struct iommufd_viommu *viommu = vdev->viommu;
+ if (vdev->destroy) + vdev->destroy(vdev); /* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */ xa_cmpxchg(&viommu->vdevs, vdev->virt_id, vdev, NULL, GFP_KERNEL); refcount_dec(&viommu->obj.users); @@ -126,6 +128,7 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd) { struct iommu_vdevice_alloc *cmd = ucmd->cmd; struct iommufd_vdevice *vdev, *curr; + size_t vdev_size = sizeof(*vdev); struct iommufd_viommu *viommu; struct iommufd_device *idev; u64 virt_id = cmd->virt_id; @@ -150,7 +153,22 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd) goto out_put_idev; }
- vdev = iommufd_object_alloc_ucmd(ucmd, vdev, IOMMUFD_OBJ_VDEVICE); + if (viommu->ops && viommu->ops->vdevice_size) { + /* + * It is a driver bug for: + * - ops->vdevice_size smaller than the core structure size + * - not implementing a pairing ops->vdevice_init op + */ + if (WARN_ON_ONCE(viommu->ops->vdevice_size < vdev_size || + !viommu->ops->vdevice_init)) { + rc = -EOPNOTSUPP; + goto out_put_idev; + } + vdev_size = viommu->ops->vdevice_size; + } + + vdev = (struct iommufd_vdevice *)_iommufd_object_alloc_ucmd( + ucmd, vdev_size, IOMMUFD_OBJ_VDEVICE); if (IS_ERR(vdev)) { rc = PTR_ERR(vdev); goto out_put_idev; @@ -168,6 +186,12 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd) goto out_put_idev; }
+ if (viommu->ops && viommu->ops->vdevice_init) { + rc = viommu->ops->vdevice_init(vdev); + if (rc) + goto out_put_idev; + } + cmd->out_vdevice_id = vdev->obj.id; rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));