[PATCH v1 5/8] x86/virt/tdx: Convert td_conf reader

[Chao Gao]

From: Dave Hansen <dave@xxxxxxxx>

Convert the "TD Configuration" class to the table-driven reader.

This class has two parts:

  - Six scalar fields (attributes_fixed{0,1}, xfam_fixed{0,1},
    num_cpuid_config, max_vcpus_per_td) that fit straight into a
    TD_SYSINFO_MAP table.

  - Two arrays (cpuid_config_leaves[] and cpuid_config_values[][])
    whose lengths come from num_cpuid_config and whose field IDs
    are computed from a base announced by the spec:

	field_id(leaves[i])     = MD_FIELD_ID_CPUID_CONFIG_LEAVES + i
	field_id(values[i][j])  = MD_FIELD_ID_CPUID_CONFIG_VALUES + i*2 + j

    The arrays can't be expressed as a static table, so read them
    explicitly after the scalar block has populated num_cpuid_config.

Bounds-check num_cpuid_config against the C array sizes before
indexing, matching the prior generated code.

Drop the corresponding function from the auto-generated file.

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.c                 | 56 +++++++++++++++++++++
 arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 33 ------------
 2 files changed, 56 insertions(+), 33 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 89055afeef68..98534e702144 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -471,6 +471,62 @@ static int get_tdx_sys_info_handoff(struct tdx_sys_info_handoff *sysinfo_handoff
 				       sysinfo_handoff);
 }
 
+#define MAP_TD_CONF(_field_id, _member)	\
+	TD_SYSINFO_MAP(_field_id, tdx_sys_info_td_conf, _member)
+
+/*
+ * Scalar fields of the "TD Configuration" class.  num_cpuid_config
+ * must be present here (and must be read before the CPUID arrays
+ * below) because it sizes them.
+ */
+static const struct tdx_sys_field td_conf_fields[] __initconst = {
+	MAP_TD_CONF(ATTRIBUTES_FIXED0,	attributes_fixed0),
+	MAP_TD_CONF(ATTRIBUTES_FIXED1,	attributes_fixed1),
+	MAP_TD_CONF(XFAM_FIXED0,	xfam_fixed0),
+	MAP_TD_CONF(XFAM_FIXED1,	xfam_fixed1),
+	MAP_TD_CONF(NUM_CPUID_CONFIG,	num_cpuid_config),
+	MAP_TD_CONF(MAX_VCPUS_PER_TD,	max_vcpus_per_td),
+};
+
+static __init int get_tdx_sys_info_td_conf(struct tdx_sys_info_td_conf *td_conf)
+{
+	int ret, i, j;
+
+	ret = read_sys_metadata_table(td_conf_fields,
+				      ARRAY_SIZE(td_conf_fields),
+				      td_conf);
+	if (ret)
+		return ret;
+
+	/*
+	 * The configurable-CPUID arrays are sized at runtime by
+	 * num_cpuid_config, so they can't be expressed in a static
+	 * TD_SYSINFO_MAP table.  Their field IDs are contiguous from
+	 * the bases announced by the spec.
+	 */
+	if (td_conf->num_cpuid_config > ARRAY_SIZE(td_conf->cpuid_config_leaves) ||
+	    td_conf->num_cpuid_config > ARRAY_SIZE(td_conf->cpuid_config_values))
+		return -EINVAL;
+
+	for (i = 0; i < td_conf->num_cpuid_config; i++) {
+		ret = read_sys_metadata_field(MD_FIELD_ID_CPUID_CONFIG_LEAVES + i,
+					      &td_conf->cpuid_config_leaves[i]);
+		if (ret)
+			return ret;
+
+		for (j = 0; j < 2; j++) {
+			u64 fid = MD_FIELD_ID_CPUID_CONFIG_VALUES + i * 2 + j;
+
+			ret = read_sys_metadata_field(fid,
+						      &td_conf->cpuid_config_values[i][j]);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
 #include "tdx_global_metadata.c"
 
 static __init int check_features(struct tdx_sys_info *sysinfo)
diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
index 0c2cc99f1af1..4d673cac0976 100644
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
@@ -7,39 +7,6 @@
  * Include this file to other C file instead.
  */
 
-static __init int get_tdx_sys_info_td_conf(struct tdx_sys_info_td_conf *sysinfo_td_conf)
-{
-	int ret = 0;
-	u64 val;
-	int i, j;
-
-	if (!ret && !(ret = read_sys_metadata_field(0x1900000300000000, &val)))
-		sysinfo_td_conf->attributes_fixed0 = val;
-	if (!ret && !(ret = read_sys_metadata_field(0x1900000300000001, &val)))
-		sysinfo_td_conf->attributes_fixed1 = val;
-	if (!ret && !(ret = read_sys_metadata_field(0x1900000300000002, &val)))
-		sysinfo_td_conf->xfam_fixed0 = val;
-	if (!ret && !(ret = read_sys_metadata_field(0x1900000300000003, &val)))
-		sysinfo_td_conf->xfam_fixed1 = val;
-	if (!ret && !(ret = read_sys_metadata_field(0x9900000100000004, &val)))
-		sysinfo_td_conf->num_cpuid_config = val;
-	if (!ret && !(ret = read_sys_metadata_field(0x9900000100000008, &val)))
-		sysinfo_td_conf->max_vcpus_per_td = val;
-	if (sysinfo_td_conf->num_cpuid_config > ARRAY_SIZE(sysinfo_td_conf->cpuid_config_leaves))
-		return -EINVAL;
-	for (i = 0; i < sysinfo_td_conf->num_cpuid_config; i++)
-		if (!ret && !(ret = read_sys_metadata_field(0x9900000300000400 + i, &val)))
-			sysinfo_td_conf->cpuid_config_leaves[i] = val;
-	if (sysinfo_td_conf->num_cpuid_config > ARRAY_SIZE(sysinfo_td_conf->cpuid_config_values))
-		return -EINVAL;
-	for (i = 0; i < sysinfo_td_conf->num_cpuid_config; i++)
-		for (j = 0; j < 2; j++)
-			if (!ret && !(ret = read_sys_metadata_field(0x9900000300000500 + i * 2 + j, &val)))
-				sysinfo_td_conf->cpuid_config_values[i][j] = val;
-
-	return ret;
-}
-
 static __init int get_tdx_sys_info(struct tdx_sys_info *sysinfo)
 {
 	int ret = 0;
-- 
2.52.0