x86/tdx: Add a helper to query maximum Quote size

Newer crypto algorithms can make Quotes larger, so guests can no longer
rely on a fixed-size buffer.

The TDX module added a new ABI that reports the largest possible Quote
size via a metadata field [1]. Add a helper to query the size instead of
exposing tdg_vm_rd() directly, as it can read arbitrary metadata fields.

The reported size covers every Quote type the platform can produce,
including SGX-based Quotes.

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[1] Intel TDX Module ABI Definitions, August 2026, TD-scope metadata
    field "TD_QUOTE_MAX_SIZE"

Signed-off-by: Peter Fang <peter.fang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Link: https://patch.msgid.link/20260930103739.2851980-6-peter.fang@intel.com

0 files changed, 0 insertions, 0 deletions