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.
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
drivers/iommu/iommufd/iommufd_private.h | 1 +
include/uapi/linux/iommufd.h | 14 +++--
drivers/iommu/iommufd/hw_pagetable.c | 73 ++++++++++++++++++++++++-
3 files changed, 81 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index a8104d9d4cef..e8f5ef550cc9 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -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)
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 302844136b02..a498d4838f9a 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -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
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index d06bf6e6c19f..982bf4a35a2b 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -57,7 +57,10 @@ void iommufd_hwpt_nested_destroy(struct iommufd_object *obj)
container_of(obj, struct iommufd_hwpt_nested, common.obj);
__iommufd_hwpt_destroy(&hwpt_nested->common);
- refcount_dec(&hwpt_nested->parent->common.obj.users);
+ if (hwpt_nested->viommu)
+ refcount_dec(&hwpt_nested->viommu->obj.users);
+ else
+ refcount_dec(&hwpt_nested->parent->common.obj.users);
}
void iommufd_hwpt_nested_abort(struct iommufd_object *obj)
@@ -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;
--
2.43.0
