On 16.06.24 г. 15:01 ч., Kai Huang wrote:
The TDX module provides "global metadata fields" for software to query.
Each metadata field is accessible by a unique "metadata field ID". TDX
supports 8/16/32/64 bits metadata element sizes. The size of each
metadata field is encoded in its associated metadata field ID.
For now the kernel only reads "TD Memory Region" (TDMR) related global
metadata fields for module initialization. All these metadata fields
are 16-bit, and the kernel only supports reading 16-bit fields.
Future changes will need to read more metadata fields with other element
sizes. To resolve this once for all, extend the existing metadata
reading code to support reading all element sizes.
Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/virt/vmx/tdx/tdx.c | 29 ++++++++++++++++-------------
arch/x86/virt/vmx/tdx/tdx.h | 3 ++-
2 files changed, 18 insertions(+), 14 deletions(-)
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 854312e97eff..4392e82a9bcb 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -270,23 +270,25 @@ static int read_sys_metadata_field(u64 field_id, u64 *data)
return 0;
}
-static int read_sys_metadata_field16(u64 field_id,
- int offset,
- void *stbuf)
+/*
+ * Read one global metadata field and store the data to a location of a
+ * given buffer specified by the offset and size (in bytes).
+ */
+static int stbuf_read_sysmd_field(u64 field_id, void *stbuf, int offset,
+ int bytes)
Actually I think opencoding read_sys_metadata_field in
stbuf_read_sysmd_field and leaving the function named as
read_sys_metadata_field would be best. The new function is still very
short and linear.
Another point - why do proliferate the offset calculations in the lower
layers of TDX. Simply pass in a buffer and a size, calculate the exact
location in the callers of the read functions.
<snip>
