[PATCH 4/9] x86/virt/tdx: Abstract reading multiple global metadata fields as a helper

Kai Huang
2024-06-16T12:01:57Z

For now the kernel only reads "TD Memory Region" (TDMR) related global
metadata fields to a 'struct tdx_tdmr_sysinfo' for initializing the TDX
module. Future changes will need to read other metadata fields that
don't make sense to populate to the "struct tdx_tdmr_sysinfo".

Now the code in get_tdx_tdmr_sysinfo() to read multiple global metadata
fields is not bound to the 'struct tdx_tdmr_sysinfo', and can support
reading all metadata element sizes. Abstract this code as a helper for
future use.

Signed-off-by: Kai Huang <kai.huang@intel.com>
---
arch/x86/virt/vmx/tdx/tdx.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 4392e82a9bcb..c68fbaf4aa15 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -304,6 +304,21 @@ struct field_mapping {
.offset = offsetof(_struct, _member), \
.size = sizeof(typeof(((_struct *)0)->_member)) }

+static int stbuf_read_sysmd_multi(const struct field_mapping *fields,
+ int nr_fields, void *stbuf)
+{
+ int i, ret;
+
+ for (i = 0; i < nr_fields; i++) {
+ ret = stbuf_read_sysmd_field(fields[i].field_id, stbuf,
+ fields[i].offset, fields[i].size);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
#define TD_SYSINFO_MAP_TDMR_INFO(_field_id, _member) \
TD_SYSINFO_MAP(_field_id, struct tdx_tdmr_sysinfo, _member)

@@ -318,18 +333,8 @@ static const struct field_mapping fields[] = {

static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
{
- int ret;
- int i;
-
/* Populate 'tdmr_sysinfo' fields using the mapping structure above: */
- for (i = 0; i < ARRAY_SIZE(fields); i++) {
- ret = stbuf_read_sysmd_field(fields[i].field_id, tdmr_sysinfo,
- fields[i].offset, fields[i].size);
- if (ret)
- return ret;
- }
-
- return 0;
+ return stbuf_read_sysmd_multi(fields, ARRAY_SIZE(fields), tdmr_sysinfo);
}

/* Calculate the actual TDMR size */
--
2.43.2