[RFC PATCH v2 03/10] x86/virt/tdx: Convert the features metadata reader

[Chao Gao <chao.gao@intel.com>]

Continue converting the metadata readers to the table-driven helper.

Add a table that pairs each field ID with the 'struct
tdx_sys_info_features' member that holds its value, and read all fields by
walking that table.

Even though the structure has only one field, add a table anyway for
symmetry with the other classes. Adding a field later then becomes a
one-line change.

Annotate the table as __initconst as it is referenced only during init.

AI was used under supervision to review code and workshop logs.

Signed-off-by: Chao Gao <chao.gao@intel.com>
---
 arch/x86/virt/vmx/tdx/tdx.c                 | 12 ++++++++++++
 arch/x86/virt/vmx/tdx/tdx.h                 |  3 +++
 arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 11 -----------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 0c8b571f5186..59e2396fea39 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -448,6 +448,18 @@ static int get_tdx_sys_info_version(struct tdx_sys_info_version *version)
 	return read_sys_metadata_table(version_mappings, version);
 }
 
+#define TDX_SYSINFO_MAP_FEATURES(_field_id, _member) \
+	TDX_SYSINFO_MAP(_field_id, struct tdx_sys_info_features, _member)
+
+static const struct field_mapping feature_mappings[] __initconst = {
+	TDX_SYSINFO_MAP_FEATURES(TDX_FEATURES0, tdx_features0),
+};
+
+static __init int get_tdx_sys_info_features(struct tdx_sys_info_features *features)
+{
+	return read_sys_metadata_table(feature_mappings, features);
+}
+
 #include "tdx_global_metadata.c"
 
 static __init int check_features(struct tdx_sys_info *sysinfo)
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index 44124f399703..582b6ff9a0bb 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -70,6 +70,9 @@
 #define TDX_MD_FIELD_ID_MAJOR_VERSION			0x0800000100000004ULL
 #define TDX_MD_FIELD_ID_UPDATE_VERSION			0x0800000100000005ULL
 
+/* Class "TDX Module Info" */
+#define TDX_MD_FIELD_ID_TDX_FEATURES0			0x0A00000300000008ULL
+
 /* TDX page types */
 #define	PT_NDA		0x0
 #define	PT_RSVD		0x1
diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
index 9510bf5f6e7d..615f4d23c5d8 100644
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
@@ -7,17 +7,6 @@
  * Include this file to other C file instead.
  */
 
-static __init int get_tdx_sys_info_features(struct tdx_sys_info_features *sysinfo_features)
-{
-	int ret = 0;
-	u64 val;
-
-	if (!ret && !(ret = read_sys_metadata_field(0x0A00000300000008, &val)))
-		sysinfo_features->tdx_features0 = val;
-
-	return ret;
-}
-
 static __init int get_tdx_sys_info_tdmr_dpamt(struct tdx_sys_info_tdmr *sysinfo_tdmr)
 {
 	int ret;
-- 
2.52.0