Commit 54b47585 authored by Nicolin Chen's avatar Nicolin Chen Committed by Jason Gunthorpe
Browse files

iommufd: Create access in vfio_iommufd_emulated_bind() 

There are needs to created iommufd_access prior to have an IOAS and set
IOAS later. Like the vfio device cdev needs to have an iommufd object
to represent the bond (iommufd_access) and IOAS replacement.

Moves the iommufd_access_create() call into vfio_iommufd_emulated_bind(),
making it symmetric with the __vfio_iommufd_access_destroy() call in the
vfio_iommufd_emulated_unbind(). This means an access is created/destroyed
by the bind()/unbind(), and the vfio_iommufd_emulated_attach_ioas() only
updates the access->ioas pointer.

Since vfio_iommufd_emulated_bind() does not provide ioas_id, drop it from
the argument list of iommufd_access_create(). Instead, add a new access
API iommufd_access_attach() to set the access->ioas pointer. Also, set
vdev->iommufd_attached accordingly, similar to the physical pathway.

Link: https://lore.kernel.org/r/20230327093351.44505-3-yi.l.liu@intel.com


Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Tested-by: default avatarTerrence Xu <terrence.xu@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Acked-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 325de950

drivers/iommu/iommufd/device.c

+30 −22
Original line number Diff line number Diff line
@@ -412,15 +412,17 @@ void iommufd_access_destroy_object(struct iommufd_object *obj) 
	struct iommufd_access *access =

		container_of(obj, struct iommufd_access, obj);



	if (access->ioas) {

		iopt_remove_access(&access->ioas->iopt, access);

	iommufd_ctx_put(access->ictx);

		refcount_dec(&access->ioas->obj.users);

		access->ioas = NULL;

	}

	iommufd_ctx_put(access->ictx);

}



/**

 * iommufd_access_create - Create an iommufd_access

 * @ictx: iommufd file descriptor

 * @ioas_id: ID for a IOMMUFD_OBJ_IOAS

 * @ops: Driver's ops to associate with the access

 * @data: Opaque data to pass into ops functions

 *
@@ -431,12 +433,10 @@ void iommufd_access_destroy_object(struct iommufd_object *obj) 
 * The provided ops are required to use iommufd_access_pin_pages().

 */

struct iommufd_access *

iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id,

iommufd_access_create(struct iommufd_ctx *ictx,

		      const struct iommufd_access_ops *ops, void *data)

{

	struct iommufd_access *access;

	struct iommufd_object *obj;

	int rc;



	/*

	 * There is no uAPI for the access object, but to keep things symmetric
@@ -449,21 +449,10 @@ iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id, 
	access->data = data;

	access->ops = ops;



	obj = iommufd_get_object(ictx, ioas_id, IOMMUFD_OBJ_IOAS);

	if (IS_ERR(obj)) {

		rc = PTR_ERR(obj);

		goto out_abort;

	}

	access->ioas = container_of(obj, struct iommufd_ioas, obj);

	iommufd_ref_to_users(obj);



	if (ops->needs_pin_pages)

		access->iova_alignment = PAGE_SIZE;

	else

		access->iova_alignment = 1;

	rc = iopt_add_access(&access->ioas->iopt, access);

	if (rc)

		goto out_put_ioas;



	/* The calling driver is a user until iommufd_access_destroy() */

	refcount_inc(&access->obj.users);
@@ -471,11 +460,6 @@ iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id, 
	iommufd_ctx_get(ictx);

	iommufd_object_finalize(ictx, &access->obj);

	return access;

out_put_ioas:

	refcount_dec(&access->ioas->obj.users);

out_abort:

	iommufd_object_abort(ictx, &access->obj);

	return ERR_PTR(rc);

}

EXPORT_SYMBOL_NS_GPL(iommufd_access_create, IOMMUFD);
@@ -494,6 +478,30 @@ void iommufd_access_destroy(struct iommufd_access *access) 
}

EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD);



int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id)

{

	struct iommufd_ioas *new_ioas;

	int rc = 0;



	if (access->ioas)

		return -EINVAL;



	new_ioas = iommufd_get_ioas(access->ictx, ioas_id);

	if (IS_ERR(new_ioas))

		return PTR_ERR(new_ioas);



	rc = iopt_add_access(&new_ioas->iopt, access);

	if (rc) {

		iommufd_put_object(&new_ioas->obj);

		return rc;

	}

	iommufd_ref_to_users(&new_ioas->obj);



	access->ioas = new_ioas;

	return 0;

}

EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD);



/**

 * iommufd_access_notify_unmap - Notify users of an iopt to stop using it

 * @iopt: iopt to work on

drivers/iommu/iommufd/selftest.c

+4 −1
Original line number Diff line number Diff line
@@ -571,7 +571,7 @@ static int iommufd_test_create_access(struct iommufd_ucmd *ucmd, 
	}



	access = iommufd_access_create(

		ucmd->ictx, ioas_id,

		ucmd->ictx,

		(flags & MOCK_FLAGS_ACCESS_CREATE_NEEDS_PIN_PAGES) ?

			&selftest_access_ops_pin :

			&selftest_access_ops,
@@ -580,6 +580,9 @@ static int iommufd_test_create_access(struct iommufd_ucmd *ucmd, 
		rc = PTR_ERR(access);

		goto out_put_fdno;

	}

	rc = iommufd_access_attach(access, ioas_id);

	if (rc)

		goto out_destroy;

	cmd->create_access.out_access_fd = fdno;

	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));

	if (rc)

drivers/vfio/iommufd.c

+17 −7
Original line number Diff line number Diff line
@@ -138,10 +138,18 @@ static const struct iommufd_access_ops vfio_user_ops = { 
int vfio_iommufd_emulated_bind(struct vfio_device *vdev,

			       struct iommufd_ctx *ictx, u32 *out_device_id)

{

	struct iommufd_access *user;



	lockdep_assert_held(&vdev->dev_set->lock);



	vdev->iommufd_ictx = ictx;

	iommufd_ctx_get(ictx);

	user = iommufd_access_create(ictx, &vfio_user_ops, vdev);

	if (IS_ERR(user)) {

		iommufd_ctx_put(ictx);

		return PTR_ERR(user);

	}

	vdev->iommufd_access = user;

	vdev->iommufd_ictx = ictx;

	return 0;

}

EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_bind);
@@ -152,6 +160,7 @@ void vfio_iommufd_emulated_unbind(struct vfio_device *vdev) 


	if (vdev->iommufd_access) {

		iommufd_access_destroy(vdev->iommufd_access);

		vdev->iommufd_attached = false;

		vdev->iommufd_access = NULL;

	}

	iommufd_ctx_put(vdev->iommufd_ictx);
@@ -161,15 +170,16 @@ EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_unbind); 


int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)

{

	struct iommufd_access *user;

	int rc;



	lockdep_assert_held(&vdev->dev_set->lock);



	user = iommufd_access_create(vdev->iommufd_ictx, *pt_id, &vfio_user_ops,

				     vdev);

	if (IS_ERR(user))

		return PTR_ERR(user);

	vdev->iommufd_access = user;

	if (vdev->iommufd_attached)

		return -EBUSY;

	rc = iommufd_access_attach(vdev->iommufd_access, *pt_id);

	if (rc)

		return rc;

	vdev->iommufd_attached = true;

	return 0;

}

EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_attach_ioas);

include/linux/iommufd.h

+2 −1
Original line number Diff line number Diff line
@@ -40,9 +40,10 @@ enum { 
};



struct iommufd_access *

iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id,

iommufd_access_create(struct iommufd_ctx *ictx,

		      const struct iommufd_access_ops *ops, void *data);

void iommufd_access_destroy(struct iommufd_access *access);

int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id);



void iommufd_ctx_get(struct iommufd_ctx *ictx);