Commit 13a75018 authored by Nicolin Chen's avatar Nicolin Chen Committed by Jason Gunthorpe
Browse files

iommufd: Allow pt_id to carry viommu_id for IOMMU_HWPT_ALLOC 

Now a vIOMMU holds a shareable nesting parent HWPT. So, it can act like
that nesting parent HWPT to allocate a nested HWPT.

Support that in the IOMMU_HWPT_ALLOC ioctl handler, and update its kdoc.

Also, add an iommufd_viommu_alloc_hwpt_nested helper to allocate a nested
HWPT for a vIOMMU object. Since a vIOMMU object holds the parent hwpt's
refcount already, increase the refcount of the vIOMMU only.

Link: https://patch.msgid.link/r/a0f24f32bfada8b448d17587adcaedeeb50a67ed.1730836219.git.nicolinc@nvidia.com


Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 69d2689e

drivers/iommu/iommufd/hw_pagetable.c

+72 −1
Original line number Diff line number Diff line
@@ -57,6 +57,9 @@ void iommufd_hwpt_nested_destroy(struct iommufd_object *obj) 
		container_of(obj, struct iommufd_hwpt_nested, common.obj);



	__iommufd_hwpt_destroy(&hwpt_nested->common);

	if (hwpt_nested->viommu)

		refcount_dec(&hwpt_nested->viommu->obj.users);

	else

		refcount_dec(&hwpt_nested->parent->common.obj.users);

}
@@ -260,6 +263,58 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx, 
	return ERR_PTR(rc);

}



/**

 * iommufd_viommu_alloc_hwpt_nested() - Get a hwpt_nested for a vIOMMU

 * @viommu: vIOMMU ojbect to associate the hwpt_nested/domain with

 * @flags: Flags from userspace

 * @user_data: user_data pointer. Must be valid

 *

 * Allocate a new IOMMU_DOMAIN_NESTED for a vIOMMU and return it as a NESTED

 * hw_pagetable.

 */

static struct iommufd_hwpt_nested *

iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags,

				 const struct iommu_user_data *user_data)

{

	struct iommufd_hwpt_nested *hwpt_nested;

	struct iommufd_hw_pagetable *hwpt;

	int rc;



	if (!user_data->len)

		return ERR_PTR(-EOPNOTSUPP);

	if (!viommu->ops || !viommu->ops->alloc_domain_nested)

		return ERR_PTR(-EOPNOTSUPP);



	hwpt_nested = __iommufd_object_alloc(

		viommu->ictx, hwpt_nested, IOMMUFD_OBJ_HWPT_NESTED, common.obj);

	if (IS_ERR(hwpt_nested))

		return ERR_CAST(hwpt_nested);

	hwpt = &hwpt_nested->common;



	hwpt_nested->viommu = viommu;

	refcount_inc(&viommu->obj.users);

	hwpt_nested->parent = viommu->hwpt;



	hwpt->domain =

		viommu->ops->alloc_domain_nested(viommu, flags, user_data);

	if (IS_ERR(hwpt->domain)) {

		rc = PTR_ERR(hwpt->domain);

		hwpt->domain = NULL;

		goto out_abort;

	}

	hwpt->domain->owner = viommu->iommu_dev->ops;



	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED)) {

		rc = -EINVAL;

		goto out_abort;

	}

	return hwpt_nested;



out_abort:

	iommufd_object_abort_and_destroy(viommu->ictx, &hwpt->obj);

	return ERR_PTR(rc);

}



int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)

{

	struct iommu_hwpt_alloc *cmd = ucmd->cmd;
@@ -316,6 +371,22 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd) 
			goto out_unlock;

		}

		hwpt = &hwpt_nested->common;

	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {

		struct iommufd_hwpt_nested *hwpt_nested;

		struct iommufd_viommu *viommu;



		viommu = container_of(pt_obj, struct iommufd_viommu, obj);

		if (viommu->iommu_dev != __iommu_get_iommu_dev(idev->dev)) {

			rc = -EINVAL;

			goto out_unlock;

		}

		hwpt_nested = iommufd_viommu_alloc_hwpt_nested(

			viommu, cmd->flags, &user_data);

		if (IS_ERR(hwpt_nested)) {

			rc = PTR_ERR(hwpt_nested);

			goto out_unlock;

		}

		hwpt = &hwpt_nested->common;

	} else {

		rc = -EINVAL;

		goto out_put_pt;

drivers/iommu/iommufd/iommufd_private.h

+1 −0
Original line number Diff line number Diff line
@@ -290,6 +290,7 @@ struct iommufd_hwpt_paging { 
struct iommufd_hwpt_nested {

	struct iommufd_hw_pagetable common;

	struct iommufd_hwpt_paging *parent;

	struct iommufd_viommu *viommu;

};



static inline bool hwpt_is_paging(struct iommufd_hw_pagetable *hwpt)

include/uapi/linux/iommufd.h

+8 −6
Original line number Diff line number Diff line
@@ -435,7 +435,7 @@ enum iommu_hwpt_data_type { 
 * @size: sizeof(struct iommu_hwpt_alloc)

 * @flags: Combination of enum iommufd_hwpt_alloc_flags

 * @dev_id: The device to allocate this HWPT for

 * @pt_id: The IOAS or HWPT to connect this HWPT to

 * @pt_id: The IOAS or HWPT or vIOMMU to connect this HWPT to

 * @out_hwpt_id: The ID of the new HWPT

 * @__reserved: Must be 0

 * @data_type: One of enum iommu_hwpt_data_type
@@ -454,11 +454,13 @@ enum iommu_hwpt_data_type { 
 * IOMMU_HWPT_DATA_NONE. The HWPT can be allocated as a parent HWPT for a

 * nesting configuration by passing IOMMU_HWPT_ALLOC_NEST_PARENT via @flags.

 *

 * A user-managed nested HWPT will be created from a given parent HWPT via

 * @pt_id, in which the parent HWPT must be allocated previously via the

 * same ioctl from a given IOAS (@pt_id). In this case, the @data_type

 * must be set to a pre-defined type corresponding to an I/O page table

 * type supported by the underlying IOMMU hardware.

 * A user-managed nested HWPT will be created from a given vIOMMU (wrapping a

 * parent HWPT) or a parent HWPT via @pt_id, in which the parent HWPT must be

 * allocated previously via the same ioctl from a given IOAS (@pt_id). In this

 * case, the @data_type must be set to a pre-defined type corresponding to an

 * I/O page table type supported by the underlying IOMMU hardware. The device

 * via @dev_id and the vIOMMU via @pt_id must be associated to the same IOMMU

 * instance.

 *

 * If the @data_type is set to IOMMU_HWPT_DATA_NONE, @data_len and

 * @data_uptr should be zero. Otherwise, both @data_len and @data_uptr