[PATCH 3/5] x86/virt/tdx: Unbind global metadata read with 'struct tdx_tdmr_sysinfo'

[Kai Huang <kai.huang@xxxxxxxxx>]

For now the kernel only reads TDMR related global metadata fields for
module initialization, and the metadata read code only works with the
'struct tdx_tdmr_sysinfo'.

KVM will need to read a bunch of non-TDMR related metadata to create and
run TDX guests.  It's essential to provide a generic metadata read
infrastructure which is not bound to any specific structure.

To start providing such infrastructure, unbound the metadata read with
the 'struct tdx_tdmr_sysinfo'.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 arch/x86/virt/vmx/tdx/tdx.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index cdcb3332bc5d..eb208da4ff63 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -273,9 +273,9 @@ static int read_sys_metadata_field(u64 field_id, u64 *data)
 
 static int read_sys_metadata_field16(u64 field_id,
 				     int offset,
-				     struct tdx_tdmr_sysinfo *ts)
+				     void *stbuf)
 {
-	u16 *ts_member = ((void *)ts) + offset;
+	u16 *st_member = stbuf + offset;
 	u64 tmp;
 	int ret;
 
@@ -287,7 +287,7 @@ static int read_sys_metadata_field16(u64 field_id,
 	if (ret)
 		return ret;
 
-	*ts_member = tmp;
+	*st_member = tmp;
 
 	return 0;
 }
@@ -297,19 +297,22 @@ struct field_mapping {
 	int offset;
 };
 
-#define TD_SYSINFO_MAP(_field_id, _member) \
-	{ .field_id = MD_FIELD_ID_##_field_id,	   \
-	  .offset   = offsetof(struct tdx_tdmr_sysinfo, _member) }
+#define TD_SYSINFO_MAP(_field_id, _struct, _member)	\
+	{ .field_id = MD_FIELD_ID_##_field_id,		\
+	  .offset   = offsetof(_struct, _member) }
+
+#define TD_SYSINFO_MAP_TDMR_INFO(_field_id, _member)	\
+	TD_SYSINFO_MAP(_field_id, struct tdx_tdmr_sysinfo, _member)
 
 static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
 {
 	/* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */
 	const struct field_mapping fields[] = {
-		TD_SYSINFO_MAP(MAX_TDMRS,	      max_tdmrs),
-		TD_SYSINFO_MAP(MAX_RESERVED_PER_TDMR, max_reserved_per_tdmr),
-		TD_SYSINFO_MAP(PAMT_4K_ENTRY_SIZE,    pamt_entry_size[TDX_PS_4K]),
-		TD_SYSINFO_MAP(PAMT_2M_ENTRY_SIZE,    pamt_entry_size[TDX_PS_2M]),
-		TD_SYSINFO_MAP(PAMT_1G_ENTRY_SIZE,    pamt_entry_size[TDX_PS_1G]),
+		TD_SYSINFO_MAP_TDMR_INFO(MAX_TDMRS,		max_tdmrs),
+		TD_SYSINFO_MAP_TDMR_INFO(MAX_RESERVED_PER_TDMR, max_reserved_per_tdmr),
+		TD_SYSINFO_MAP_TDMR_INFO(PAMT_4K_ENTRY_SIZE,    pamt_entry_size[TDX_PS_4K]),
+		TD_SYSINFO_MAP_TDMR_INFO(PAMT_2M_ENTRY_SIZE,    pamt_entry_size[TDX_PS_2M]),
+		TD_SYSINFO_MAP_TDMR_INFO(PAMT_1G_ENTRY_SIZE,    pamt_entry_size[TDX_PS_1G]),
 	};
 	int ret;
 	int i;
-- 
2.43.2