linux-kernel - [PATCH v2 0/2] x86/virt/tdx: Print TDX module version to dmesg

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Message-Id: <20260109-tdx_print_module_version-v2-0-e10e4ca5b450@intel.com>
Date: Fri, 09 Jan 2026 12:14:29 -0700
From: Vishal Verma <vishal.l.verma@...el.com>
To: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev, 
 kvm@...r.kernel.org
Cc: x86@...nel.org, Chao Gao <chao.gao@...el.com>, 
 Dan Williams <dan.j.williams@...el.com>, Kai Huang <kai.huang@...el.com>, 
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, 
 "H. Peter Anvin" <hpa@...or.com>, Kiryl Shutsemau <kas@...nel.org>, 
 Rick Edgecombe <rick.p.edgecombe@...el.com>, 
 Vishal Verma <vishal.l.verma@...el.com>
Subject: [PATCH v2 0/2] x86/virt/tdx: Print TDX module version to dmesg

=== Problem & Solution ===

Currently, there is neither an ABI, nor any other way to determine from
the host system, what version of the TDX module is running. A sysfs ABI
for this has been proposed in [1], but it may need additional discussion.

Many/most TDX developers already carry patches like this in their
development branches. It can be tricky to know which TDX module is
actually loaded on a system, and so this functionality has been needed
regularly for development and processing bug reports. Hence, it is
prudent to break out the patches to retrieve and print the TDX module
version, as those parts are very straightforward, and get some level of
debugability and traceability for TDX host systems.

=== Dependencies ===

None. This is based on v6.19-rc4, and applies cleanly to tip.git.

=== Patch details ===

Patch 1 is a prerequisite that adds the infrastructure to retrieve the
TDX module version from its global metadata. This was originally posted in [2].

Patch 2 is based on a patch from Kai Huang [3], and prints the version to
dmesg during init.

=== Testing ===

This has passed the usual suite of tests, including successful 0day
builds, KVM Unit tests, KVM selftests, a TD creation smoke test, and
selected KVM tests from the Avocado test suite.

[1]: https://lore.kernel.org/all/20260105074350.98564-1-chao.gao@intel.com/
[2]: https://lore.kernel.org/all/20260105074350.98564-2-chao.gao@intel.com/
[3]: https://lore.kernel.org/all/57eaa1b17429315f8b5207774307f3c1dd40cf37.1730118186.git.kai.huang@intel.com/

Signed-off-by: Vishal Verma <vishal.l.verma@...el.com>
---
Changes in v2:
- Collect review tags (Kiryl, Rick)
- Reword commit messages for clarity (Rick)
- Move the version print get_tdx_sys_info() (Kiryl, Dave)
- Link to v1: https://patch.msgid.link/20260107-tdx_print_module_version-v1-0-822baa56762d@intel.com

---
Chao Gao (1):
      x86/virt/tdx: Retrieve TDX module version

Vishal Verma (1):
      x86/virt/tdx: Print TDX module version during init

 arch/x86/include/asm/tdx_global_metadata.h  |  7 +++++++
 arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 22 ++++++++++++++++++++++
 2 files changed, 29 insertions(+)
---
base-commit: 9ace4753a5202b02191d54e9fdf7f9e3d02b85eb
change-id: 20260107-tdx_print_module_version-e4ca7edc2022

Best regards,
--  
Vishal Verma <vishal.l.verma@...el.com>