[PATCH v2 06/11] iommufd: IOMMU_HWPT_ALLOC allocation with user data

[Yi Liu <yi.l.liu@intel.com>]

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 | 87 +++++++++++++++++++++++++---
 drivers/iommu/iommufd/main.c         |  2 +-
 include/uapi/linux/iommufd.h         | 32 +++++++++-
 3 files changed, 112 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 73d7d9d07726..e84270eb6e49 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -184,11 +184,15 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 
 int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 {
+	struct iommufd_hw_pagetable *hwpt, *parent = NULL;
+	union iommu_domain_user_data *data = NULL;
 	struct iommu_hwpt_alloc *cmd = ucmd->cmd;
-	struct iommufd_hw_pagetable *hwpt;
+	struct iommufd_object *pt_obj;
+	const struct iommu_ops *ops;
 	struct iommufd_device *idev;
 	struct iommufd_ioas *ioas;
-	int rc;
+	int klen = 0;
+	int rc = 0;
 
 	if (cmd->flags || cmd->__reserved)
 		return -EOPNOTSUPP;
@@ -197,15 +201,81 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 	if (IS_ERR(idev))
 		return PTR_ERR(idev);
 
-	ioas = iommufd_get_ioas(ucmd->ictx, cmd->pt_id);
-	if (IS_ERR(ioas)) {
-		rc = PTR_ERR(ioas);
+	ops = dev_iommu_ops(idev->dev);
+
+	/*
+	 * All drivers support IOMMU_HWPT_TYPE_DEFAULT, so pass it through.
+	 * For any other hwpt_type, check the ops->domain_alloc_user_data_len
+	 * presence and its result.
+	 */
+	if (cmd->hwpt_type != IOMMU_HWPT_TYPE_DEFAULT) {
+		if (!ops->domain_alloc_user_data_len) {
+			rc = -EOPNOTSUPP;
+			goto out_put_idev;
+		}
+		klen = ops->domain_alloc_user_data_len(cmd->hwpt_type);
+		if (WARN_ON(klen < 0)) {
+			rc = -EINVAL;
+			goto out_put_pt;
+		}
+	}
+
+	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 hwpt_type is !IOMMU_HWPT_TYPE_DEFAULT */
+		if (cmd->hwpt_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;
+	}
+
+	if (klen) {
+		if (!cmd->data_len) {
+			rc = -EINVAL;
+			goto out_put_pt;
+		}
+
+		data = kzalloc(sizeof(*data), GFP_KERNEL);
+		if (!data) {
+			rc = -ENOMEM;
+			goto out_put_pt;
+		}
+
+		rc = copy_struct_from_user(data, sizeof(*data),
+					   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);
 	if (IS_ERR(hwpt)) {
 		rc = PTR_ERR(hwpt);
 		goto out_unlock;
@@ -222,7 +292,10 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 	iommufd_object_abort_and_destroy(ucmd->ictx, &hwpt->obj);
 out_unlock:
 	mutex_unlock(&ioas->mutex);
-	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 5c24e8971f09..ac81403ba78e 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -302,7 +302,7 @@ 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 e9d42838dcbd..699e735828db 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
+ * @hwpt_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 HWPT will be created with the IOVA mappings from the given IOAS.
+ * A kernel-managed HWPT will be created with the mappings from the given IOAS.
+ * The @hwpt_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 @hwpt_type must not be set to IOMMU_HWPT_TYPE_DEFAULT but a
+ * pre-defined type corresponding to the underlying IOMMU hardware.
+ *
+ * If the @hwpt_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.
+ *
+ * +==============================+=====================================+===========+
+ * | @hwpt_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 hwpt_type;
+	__u32 data_len;
+	__aligned_u64 data_uptr;
 };
 #define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)
 
-- 
2.34.1