On Sun, Mar 15, 2026 at 06:58:36AM -0700, Chao Gao wrote:

tdx_sysinfo contains all metadata of the active TDX module, including
versions, supported features, and TDMR/TDCS/TDVPS information etc. These
values may change over updates. Blindly refreshing the entire tdx_sysinfo
could disrupt running software, as it may subtly rely on the previous state
unless proven otherwise.

Adopt a conservative approach, like microcode updates, by only refreshing
version information that does not affect functionality, while ignoring
all other changes. This is acceptable as new modules are required to
maintain backward compatibility.

Any updates to metadata beyond versions should be justified and reviewed on
a case-by-case basis.

Note that preallocating a tdx_sys_info buffer before updates is to avoid
having to handle -ENOMEM when updating tdx_sysinfo after a successful
update.

Signed-off-by: Chao Gao <redacted>
Reviewed-by: Xu Yilun <redacted>
Reviewed-by: Tony Lindgren <redacted>
Reviewed-by: Kai Huang <redacted>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>

Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>

-- 
  Kiryl Shutsemau / Kirill A. Shutemov