Commit ed42eee7 authored by Nicolin Chen's avatar Nicolin Chen Committed by Jason Gunthorpe
Browse files

iommufd/viommu: Add driver-defined vDEVICE support 

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.

Link: https://patch.msgid.link/r/1e751c01da7863c669314d8e27fdb89eabcf5605.1752126748.git.nicolinc@nvidia.com


Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarPranjal Shrivastava <praan@google.com>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 27b77ea5

drivers/iommu/iommufd/iommufd_private.h

+0 −12
Original line number Diff line number Diff line
@@ -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 Intel VT-d

	 */

	u64 virt_id;

};



#ifdef CONFIG_IOMMUFD_TEST

int iommufd_test(struct iommufd_ucmd *ucmd);

void iommufd_selftest_destroy(struct iommufd_object *obj);

drivers/iommu/iommufd/viommu.c

+25 −1
Original line number Diff line number Diff line
@@ -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));

include/linux/iommufd.h

+31 −0
Original line number Diff line number Diff line
@@ -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 Intel VT-d

	 */

	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