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

On 5/11/2023 10:38 PM, Yi Liu wrote:

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

s/provide/to provide

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,

s/parameter/parameters

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;
  

• }
  

Would it be better if the later check "klen" is moved here ?     if (klen) {                 [...]     } If this check fails here, there's no need to execute the code after it. If this path is not executed, "klen" is 0, and there's no need to check it. Do I understand it right ?

Thanks, Jingqi

• }
• 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)