[PATCH v1 2/8] x86/virt/tdx: Name the TDX module global metadata field IDs

[Chao Gao]

From: Dave Hansen <dave@xxxxxxxx>

tdx_global_metadata.c currently identifies each field by a bare 64-bit hex
literal, extracted from the JSON file by an out-of-tree script:

	if (!ret && !(ret = read_sys_metadata_field(0x9100000100000008, &val)))
		sysinfo_tdmr->max_tdmrs = val;

That is unreviewable on its own. Verifying any one line requires the
reviewer to cross-reference the JSON file.

Add MD_FIELD_ID_<NAME> constants for every global metadata field the kernel
currently reads (Version, Features, etc), grouped by class. This follows
how the kernel handles ABI-defined literals elsewhere. The IDs can then be
checked against the spec in one pass, and the read sites become readable
without the JSON file.

The hex literals in tdx_global_metadata.c are left alone because that file
will be replaced by a table-driven reader in the following patches.

No functional change intended.

Assisted-by: Claude:claude-opus-5
Not-yet-signed-off-by: Dave Hansen <dave@xxxxxxxx>
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
 arch/x86/virt/vmx/tdx/tdx.h | 51 +++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index bdfd0e1e337a..5f567cb6c07a 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -58,6 +58,57 @@
  */
 #define TDX_VERSION_SHIFT		16
 
+/*
+ * Global Scope Metadata field IDs.
+ *
+ * See "Global-Scope (TDX Module) Metadata" in the Intel TDX Module ABI
+ * spec.
+ *
+ * A field ID is a 64-bit value that encodes the metadata "Class"
+ * (which Linux mirrors in 'struct tdx_sys_info' sub-structures),
+ * the element size, and a per-class field index. Each ID below
+ * is paired with the C member that holds its value.
+ */
+
+/* Class "TDX Module Version" */
+#define MD_FIELD_ID_MINOR_VERSION		0x0800000100000003ULL
+#define MD_FIELD_ID_MAJOR_VERSION		0x0800000100000004ULL
+#define MD_FIELD_ID_UPDATE_VERSION		0x0800000100000005ULL
+
+/* Class "TDX Features" */
+#define MD_FIELD_ID_TDX_FEATURES0		0x0A00000300000008ULL
+
+/* Class "TDMR Info" */
+#define MD_FIELD_ID_MAX_TDMRS			0x9100000100000008ULL
+#define MD_FIELD_ID_MAX_RESERVED_PER_TDMR	0x9100000100000009ULL
+#define MD_FIELD_ID_PAMT_4K_ENTRY_SIZE		0x9100000100000010ULL
+#define MD_FIELD_ID_PAMT_2M_ENTRY_SIZE		0x9100000100000011ULL
+#define MD_FIELD_ID_PAMT_1G_ENTRY_SIZE		0x9100000100000012ULL
+
+/* Class "TD Control Structures" */
+#define MD_FIELD_ID_TDR_BASE_SIZE		0x9800000100000000ULL
+#define MD_FIELD_ID_TDCS_BASE_SIZE		0x9800000100000100ULL
+#define MD_FIELD_ID_TDVPS_BASE_SIZE		0x9800000100000200ULL
+
+/* Class "TD Configuration" */
+#define MD_FIELD_ID_ATTRIBUTES_FIXED0		0x1900000300000000ULL
+#define MD_FIELD_ID_ATTRIBUTES_FIXED1		0x1900000300000001ULL
+#define MD_FIELD_ID_XFAM_FIXED0			0x1900000300000002ULL
+#define MD_FIELD_ID_XFAM_FIXED1			0x1900000300000003ULL
+#define MD_FIELD_ID_NUM_CPUID_CONFIG		0x9900000100000004ULL
+#define MD_FIELD_ID_MAX_VCPUS_PER_TD		0x9900000100000008ULL
+
+/* Class "TDX Module Handoff" */
+#define MD_FIELD_ID_MODULE_HV			0x8900000100000000ULL
+
+/*
+ * Base IDs for the configurable-CPUID arrays.  The field ID of leaf
+ * index @i is BASE + i; for the values array, sub-entry @j of index
+ * @i is BASE + i*2 + j.
+ */
+#define MD_FIELD_ID_CPUID_CONFIG_LEAVES		0x9900000300000400ULL
+#define MD_FIELD_ID_CPUID_CONFIG_VALUES		0x9900000300000500ULL
+
 /* TDX page types */
 #define	PT_NDA		0x0
 #define	PT_RSVD		0x1
-- 
2.52.0