From: Liu, Yi L yi.l.liu@intel.com Sent: Thursday, May 11, 2023 10:30 PM
+int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) +{
- struct iommu_hw_info *cmd = ucmd->cmd;
- unsigned int length = 0, data_len;
- struct iommufd_device *idev;
- const struct iommu_ops *ops;
- void *data = NULL;
- int rc = 0;
- if (cmd->flags || cmd->__reserved || !cmd->data_len)
return -EOPNOTSUPP;- idev = iommufd_get_device(ucmd, cmd->dev_id);
- if (IS_ERR(idev))
return PTR_ERR(idev);- ops = dev_iommu_ops(idev->dev);
- if (!ops->hw_info)
goto done;- /* driver has hw_info callback should have a unique hw_info_type */
- if (ops->hw_info_type == IOMMU_HW_INFO_TYPE_NONE) {
pr_warn_ratelimited("iommu driver set an invalid type\n");rc = -ENODEV;goto out_err;- }
this should be a WARN_ON_ONCE() since it's a driver bug.
- data = ops->hw_info(idev->dev, &data_len);
- if (IS_ERR(data)) {
rc = PTR_ERR(data);goto out_err;- }
- length = min(cmd->data_len, data_len);
- if (copy_to_user(u64_to_user_ptr(cmd->data_ptr), data, length)) {
rc = -EFAULT;goto out_err;- }
- /*
* Zero the trailing bytes if the user buffer is bigger than the* data size kernel actually has.*/- if (length < cmd->data_len) {
rc = iommufd_zero_fill_user(cmd->data_ptr + length,cmd->data_len - length);if (rc)goto out_err;- }
+done:
- cmd->data_len = length;
- cmd->out_data_type = ops->hw_info_type;
- rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
the 'done' label should be moved before above zero_fill. Otherwise in !ops->hw_info case the user buffer is not cleared.
union ucmd_buffer { struct iommu_destroy destroy; struct iommu_hwpt_alloc hwpt;
- struct iommu_hw_info info;
follow alphabetic order this should be ahead of hwpt.
@@ -302,6 +303,8 @@ 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),
- IOCTL_OP(IOMMU_DEVICE_GET_HW_INFO,
iommufd_device_get_hw_info,
struct iommu_hw_info, __reserved),
before IOMMU_HWPT_ALLOC
+/**
- struct iommu_hw_info - ioctl(IOMMU_DEVICE_GET_HW_INFO)
- @size: sizeof(struct iommu_hw_info)
- @flags: Must be 0
- @dev_id: The device bound to the iommufd
- @data_len: Input the length of the user buffer in bytes. Output the
length of data filled in the user buffer.
- @data_ptr: Pointer to the user buffer
- @out_data_type: Output the iommu hardware info type as defined by
enum iommu_hw_info_type.
- @__reserved: Must be 0
- Query the hardware iommu information for given device which has been
- bound to iommufd. @data_len is the size of the buffer which captures
- iommu type specific data and the data will be filled. Trailing bytes
- are zeroed if the user buffer is larger than the data kernel has.
- The type specific data would be used to sync capability between the
- virtual IOMMU and the hardware IOMMU. e.g. nested translation
requires
- to check the hardware IOMMU capability so guest stage-1 page table
- uses a format compatible to the hardware IOMMU.
- The @out_data_type will be filled if the ioctl succeeds. It would
- be used to decode the data filled in the buffer pointed by @data_ptr.
- */
+struct iommu_hw_info {
- __u32 size;
- __u32 flags;
- __u32 dev_id;
- __u32 data_len;
- __aligned_u64 data_ptr;
- __u32 out_data_type;
- __u32 __reserved;
it's unusual to have reserved field in the end. It makes more sense to move data_ptr to the end to make it meaningful.
+}; +#define IOMMU_DEVICE_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_GET_HW_INFO) #endif
Here we have a naming confusion.
'IOMMU' is the prefix of iommufd ioctls.
'DEVICE' is the subjective.
Then "GET_HW_INFO" implies getting hardware info related to this device. then it should not be restricted to the iommu info.
with that it's clearer to call it IOMMU_DEVICE_GET_IOMMU_INFO.
similarly for struct iommu_hw_info.
'iommu' is the prefix for all iommufd ioctl structures.
then 'hw_info' is too broard.
iommu_device_iommu_info reads better? though having two iommu's in the name is a little bit annoying...