1.. SPDX-License-Identifier: GPL-2.0
2
3===================================================================
4TDX Guest API Documentation
5===================================================================
6
71. General description
8======================
9
10The TDX guest driver exposes IOCTL interfaces via the /dev/tdx-guest misc
11device to allow userspace to get certain TDX guest-specific details.
12
132. API description
14==================
15
16In this section, for each supported IOCTL, the following information is
17provided along with a generic description.
18
19:Input parameters: Parameters passed to the IOCTL and related details.
20:Output: Details about output data and return value (with details about
21         the non common error values).
22
232.1 TDX_CMD_GET_REPORT0
24-----------------------
25
26:Input parameters: struct tdx_report_req
27:Output: Upon successful execution, TDREPORT data is copied to
28         tdx_report_req.tdreport and return 0. Return -EINVAL for invalid
29         operands, -EIO on TDCALL failure or standard error number on other
30         common failures.
31
32The TDX_CMD_GET_REPORT0 IOCTL can be used by the attestation software to get
33the TDREPORT0 (a.k.a. TDREPORT subtype 0) from the TDX module using
34TDCALL[TDG.MR.REPORT].
35
36A subtype index is added at the end of this IOCTL CMD to uniquely identify the
37subtype-specific TDREPORT request. Although the subtype option is mentioned in
38the TDX Module v1.0 specification, section titled "TDG.MR.REPORT", it is not
39currently used, and it expects this value to be 0. So to keep the IOCTL
40implementation simple, the subtype option was not included as part of the input
41ABI. However, in the future, if the TDX Module supports more than one subtype,
42a new IOCTL CMD will be created to handle it. To keep the IOCTL naming
43consistent, a subtype index is added as part of the IOCTL CMD.
44
45Reference
46---------
47
48TDX reference material is collected here:
49
50https://www.intel.com/content/www/us/en/developer/articles/technical/intel-trust-domain-extensions.html
51
52The driver is based on TDX module specification v1.0 and TDX GHCI specification v1.0.
53