From: Dave Hansen The auto-generated tdx_global_metadata.c populates each member of 'struct tdx_sys_info' with a chain like if (!ret && !(ret = read_sys_metadata_field(0x..., &val))) sysinfo_xxx->member = val; repeated once per field, with a bare hex literal for the field ID and an implicit narrowing assignment. Reading it requires the JSON file, and reviewing any change to it requires the out-of-tree script. Replace it with a small table-driven reader. Each table entry pairs a named MD_FIELD_ID_* with the C member that holds its value: #define MAP_FEATURES(_field_id, _member) \ TD_SYSINFO_MAP(_field_id, tdx_sys_info_features, _member) static const struct tdx_sys_field features_fields[] __initconst = { MAP_FEATURES(TDX_FEATURES0, tdx_features0), }; TD_SYSINFO_MAP() derives the destination offset and width from the struct via offsetof()/sizeof_field(). Add read_sys_metadata_table() to walk such a table, reading each field and populating the C struct. Three things fall out of this table-driven reader, all of which matter now that the code is hand-maintained rather than auto-generated: - The field-to-member pairing becomes data rather than code embedded in control flow. - The read logic exists once instead of once per field. - The width is recorded explicitly instead of being implied by a narrowing assignment. Convert the 'features' class only, as an example. The remaining classes follow in later patches. Assisted-by: Claude:claude-opus-5 Not-yet-signed-off-by: Dave Hansen Signed-off-by: Chao Gao --- arch/x86/virt/vmx/tdx/tdx.c | 60 +++++++++++++++++++++ arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 11 ---- 2 files changed, 60 insertions(+), 11 deletions(-) diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index 42df8ea464c4..fb21433e7851 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -347,6 +347,66 @@ static int read_sys_metadata_field(u64 field_id, u64 *data) return 0; } +/* + * Mapping between a TDX global metadata field and the C member that + * holds its value. Use TD_SYSINFO_MAP() to populate entries. + */ +struct tdx_sys_field { + u64 field_id; + u16 offset; + u8 size; +}; + +#define TD_SYSINFO_MAP(_field_id, _struct, _member) \ + { \ + .field_id = MD_FIELD_ID_##_field_id, \ + .offset = offsetof(struct _struct, _member), \ + .size = sizeof_field(struct _struct, _member), \ + } + +/* + * Walk a table of TDX global metadata fields, read each via TDH.SYS.RD, + * and store the result into the matching C member of *@base. + */ +static int read_sys_metadata_table(const struct tdx_sys_field *fields, + int nr_fields, void *base) +{ + int i, ret; + u64 val; + + for (i = 0; i < nr_fields; i++) { + const struct tdx_sys_field *f = &fields[i]; + + ret = read_sys_metadata_field(f->field_id, &val); + if (ret) + return ret; + + switch (f->size) { + case 1: *(u8 *)(base + f->offset) = val; break; + case 2: *(u16 *)(base + f->offset) = val; break; + case 4: *(u32 *)(base + f->offset) = val; break; + case 8: *(u64 *)(base + f->offset) = val; break; + default: + return -EINVAL; + } + } + return 0; +} + +#define MAP_FEATURES(_field_id, _member) \ + TD_SYSINFO_MAP(_field_id, tdx_sys_info_features, _member) + +static const struct tdx_sys_field features_fields[] __initconst = { + MAP_FEATURES(TDX_FEATURES0, tdx_features0), +}; + +static __init int get_tdx_sys_info_features(struct tdx_sys_info_features *sysinfo_features) +{ + return read_sys_metadata_table(features_fields, + ARRAY_SIZE(features_fields), + sysinfo_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_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c index e49c300f23d4..e69c655a91a0 100644 --- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c +++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c @@ -22,17 +22,6 @@ static int get_tdx_sys_info_version(struct tdx_sys_info_version *sysinfo_version return ret; } -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(struct tdx_sys_info_tdmr *sysinfo_tdmr) { int ret = 0; -- 2.52.0