[PATCH v1 02/16] iommufd/viommu: Allow driver-specific user data for a vIOMMU object

Nicolin Chen
2025-04-11T06:38:25Z

The new type of vIOMMU for tegra241-cmdqv driver needs a driver-specific
user data. So, add data_len/uptr to the iommu_viommu_alloc uAPI and pass
it in via the viommu_alloc iommu op.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
include/uapi/linux/iommufd.h | 6 ++++++
drivers/iommu/iommufd/viommu.c | 8 +++++++-
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index f29b6c44655e..cc90299a08d9 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -965,6 +965,9 @@ enum iommu_viommu_type {
* @dev_id: The device's physical IOMMU will be used to back the virtual IOMMU
* @hwpt_id: ID of a nesting parent HWPT to associate to
* @out_viommu_id: Output virtual IOMMU ID for the allocated object
+ * @data_len: Length of the type specific data
+ * @__reserved: Must be 0
+ * @data_uptr: User pointer to an array of driver-specific virtual IOMMU data
*
* Allocate a virtual IOMMU object, representing the underlying physical IOMMU's
* virtualization support that is a security-isolated slice of the real IOMMU HW
@@ -985,6 +988,9 @@ struct iommu_viommu_alloc {
__u32 dev_id;
__u32 hwpt_id;
__u32 out_viommu_id;
+ __u32 data_len;
+ __u32 __reserved;
+ __aligned_u64 data_uptr;
};
#define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)

diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index b861ca49d723..3d4d325adeaa 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -17,6 +17,11 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
{
struct iommu_viommu_alloc *cmd = ucmd->cmd;
+ const struct iommu_user_data user_data = {
+ .type = cmd->type,
+ .uptr = u64_to_user_ptr(cmd->data_uptr),
+ .len = cmd->data_len,
+ };
struct iommufd_hwpt_paging *hwpt_paging;
struct iommufd_viommu *viommu;
struct iommufd_device *idev;
@@ -48,7 +53,8 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
}

viommu = ops->viommu_alloc(idev->dev, hwpt_paging->common.domain,
- ucmd->ictx, cmd->type, NULL);
+ ucmd->ictx, cmd->type,
+ user_data.len ? &user_data : NULL);
if (IS_ERR(viommu)) {
rc = PTR_ERR(viommu);
goto out_put_hwpt;
--
2.43.0