[PATCH 06/12] iommufd: IOMMU_HWPT_ALLOC allocation with user data

Yi Liu
2023-03-09T08:10:16Z

IOMMU_HWPT_ALLOC already supports iommu_domain allocation for usersapce.
But it can only allocate hw_pagetables linked with IOAS. There are needs
to support hw_pagetable allocation with parameters specified by user. For
example, in nested translation, user needs to allocate hw_pagetable for
the stage-1 translation (e.g. a single I/O page table or a set of I/O page
tables) with user data. It also needs provide a stage-2 hw_pagetable which
is linked to the GPA IOAS.

This extends IOMMU_HWPT_ALLOC to accept user specified parameter and hwpt
ID in @pt_id field. Such as the user-managed stage-1 hwpt, which requires
a parent hwpt to point to stage-2 translation.

enum iommu_hwpt_type is defined to differentiate the user parameters use
by different usages. For the allocations that don't require user parameter,
IOMMU_HWPT_TYPE_DEFAULT is defined for backward compatibility. Other types
would be added by future iommu vendor driver extensions.

Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/hw_pagetable.c | 94 +++++++++++++++++++++++++---
drivers/iommu/iommufd/main.c | 2 +-
include/uapi/linux/iommufd.h | 30 +++++++++
3 files changed, 115 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 6e45ec0a66fa..64e7cf7142e1 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -165,34 +165,106 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
return ERR_PTR(rc);
}

+/*
+ * size of page table type specific data, indexed by
+ * enum iommu_hwpt_type.
+ */
+static const size_t iommufd_hwpt_alloc_data_size[] = {
+ [IOMMU_HWPT_TYPE_DEFAULT] = 0,
+};
+
int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
{
struct iommu_hwpt_alloc *cmd = ucmd->cmd;
- struct iommufd_hw_pagetable *hwpt;
+ struct iommufd_hw_pagetable *hwpt, *parent = NULL;
+ struct iommufd_object *pt_obj;
struct iommufd_device *idev;
struct iommufd_ioas *ioas;
+ const struct iommu_ops *ops;
+ void *data = NULL;
+ u32 klen;
int rc;

- if (cmd->flags)
+ if (cmd->__reserved || cmd->flags)
return -EOPNOTSUPP;

idev = iommufd_get_device(ucmd, cmd->dev_id);
if (IS_ERR(idev))
return PTR_ERR(idev);

- ioas = iommufd_get_ioas(ucmd, cmd->pt_id);
- if (IS_ERR(ioas)) {
- rc = PTR_ERR(ioas);
+ ops = dev_iommu_ops(idev->dev);
+ if (!ops) {
+ rc = -EOPNOTSUPP;
goto out_put_idev;
}

+ /* Only support IOMMU_HWPT_TYPE_DEFAULT for now */
+ if (cmd->data_type != IOMMU_HWPT_TYPE_DEFAULT) {
+ rc = -EINVAL;
+ goto out_put_idev;
+ }
+
+ pt_obj = iommufd_get_object(ucmd->ictx, cmd->pt_id, IOMMUFD_OBJ_ANY);
+ if (IS_ERR(pt_obj)) {
+ rc = -EINVAL;
+ goto out_put_idev;
+ }
+
+ switch (pt_obj->type) {
+ case IOMMUFD_OBJ_IOAS:
+ ioas = container_of(pt_obj, struct iommufd_ioas, obj);
+ break;
+ case IOMMUFD_OBJ_HW_PAGETABLE:
+ /* pt_id points HWPT only when data_type is !IOMMU_HWPT_TYPE_DEFAULT */
+ if (cmd->data_type == IOMMU_HWPT_TYPE_DEFAULT) {
+ rc = -EINVAL;
+ goto out_put_pt;
+ }
+
+ parent = container_of(pt_obj, struct iommufd_hw_pagetable, obj);
+ /*
+ * Cannot allocate user-managed hwpt linking to auto_created
+ * hwpt. If the parent hwpt is already a user-managed hwpt,
+ * don't allocate another user-managed hwpt linking to it.
+ */
+ if (parent->auto_domain || parent->parent) {
+ rc = -EINVAL;
+ goto out_put_pt;
+ }
+ ioas = parent->ioas;
+ break;
+ default:
+ rc = -EINVAL;
+ goto out_put_pt;
+ }
+
+ klen = iommufd_hwpt_alloc_data_size[cmd->data_type];
+ if (klen) {
+ if (!cmd->data_len) {
+ rc = -EINVAL;
+ goto out_put_pt;
+ }
+
+ data = kzalloc(klen, GFP_KERNEL);
+ if (!data) {
+ rc = -ENOMEM;
+ goto out_put_pt;
+ }
+
+ rc = copy_struct_from_user(data, klen,
+ u64_to_user_ptr(cmd->data_uptr),
+ cmd->data_len);
+ if (rc)
+ goto out_free_data;
+ }
+
mutex_lock(&ioas->mutex);
hwpt = iommufd_hw_pagetable_alloc(ucmd->ictx, ioas, idev,
- NULL, NULL, false);
+ parent, data, false);
mutex_unlock(&ioas->mutex);
if (IS_ERR(hwpt)) {
rc = PTR_ERR(hwpt);
- goto out_put_ioas;
+ goto out_free_data;
}

cmd->out_hwpt_id = hwpt->obj.id;
@@ -200,12 +272,14 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
if (rc)
goto out_hwpt;
iommufd_object_finalize(ucmd->ictx, &hwpt->obj);
- goto out_put_ioas;
+ goto out_free_data;

out_hwpt:
iommufd_object_abort_and_destroy(ucmd->ictx, &hwpt->obj);
-out_put_ioas:
- iommufd_put_object(&ioas->obj);
+out_free_data:
+ kfree(data);
+out_put_pt:
+ iommufd_put_object(pt_obj);
out_put_idev:
iommufd_put_object(&idev->obj);
return rc;
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index f079c0bda46b..7ab1e2c638a1 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -295,7 +295,7 @@ struct iommufd_ioctl_op {
static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id),
IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc,
- __reserved),
+ data_uptr),
IOCTL_OP(IOMMU_DEVICE_GET_HW_INFO, iommufd_device_get_hw_info,
struct iommu_hw_info, __reserved),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 4ac525897b82..48781ff40a37 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -347,6 +347,14 @@ struct iommu_vfio_ioas {
};
#define IOMMU_VFIO_IOAS _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VFIO_IOAS)

+/**
+ * enum iommu_hwpt_type - IOMMU HWPT Type
+ * @IOMMU_HWPT_TYPE_DEFAULT: default
+ */
+enum iommu_hwpt_type {
+ IOMMU_HWPT_TYPE_DEFAULT,
+};
+
/**
* struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
* @size: sizeof(struct iommu_hwpt_alloc)
@@ -355,12 +363,31 @@ struct iommu_vfio_ioas {
* @pt_id: The IOAS 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_type
+ * @data_len: Length of the type specific data
+ * @data_uptr: User pointer to the type specific data
*
* Explicitly allocate a hardware page table object. This is the same object
* type that is returned by iommufd_device_attach() and represents the
* underlying iommu driver's iommu_domain kernel object.
*
* A normal HWPT will be created with the mappings from the given IOAS.
+ * The @data_type for its allocation can be set to IOMMU_HWPT_TYPE_DEFAULT, or
+ * another type (being listed below) to specialize a kernel-managed HWPT.
+ *
+ * A user-managed 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. The @data_type must not be set to IOMMU_HWPT_TYPE_DEFAULT but a
+ * pre-defined type corresponding to the underlying IOMMU hardware.
+ *
+ * If the @data_type is set to IOMMU_HWPT_TYPE_DEFAULT, both the @data_len and
+ * the @data_uptr will be ignored. Otherwise, both of them must be given.
+ *
+ * +==============================+=====================================+===========+
+ * | @data_type | Data structure in @data_uptr | @pt_id |
+ * +------------------------------+-------------------------------------+-----------+
+ * | IOMMU_HWPT_TYPE_DEFAULT | N/A | IOAS |
+ * +------------------------------+-------------------------------------+-----------+
*/
struct iommu_hwpt_alloc {
__u32 size;
@@ -369,6 +396,9 @@ struct iommu_hwpt_alloc {
__u32 pt_id;
__u32 out_hwpt_id;
__u32 __reserved;
+ __u32 data_type;
+ __u32 data_len;
+ __aligned_u64 data_uptr;
};
#define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)

--
2.34.1