[PATCH v19 033/130] KVM: TDX: Add helper function to read TDX metadata in array

isaku.yamahata
2024-02-26T08:28:00Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

To read meta data in series, use table.
Instead of metadata_read(fid0, &data0); metadata_read(...); ...
table = { {fid0, &data0}, ...}; metadata-read(tables).
TODO: Once the TDX host code introduces its framework to read TDX metadata,
drop this patch and convert the code that uses this.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
v18:
- newly added
---
arch/x86/kvm/vmx/tdx.c | 45 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index cde971122c1e..dce21f675155 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -6,6 +6,7 @@
#include "capabilities.h"
#include "x86_ops.h"
#include "x86.h"
+#include "tdx_arch.h"
#include "tdx.h"

#undef pr_fmt
@@ -39,6 +40,50 @@ static void __used tdx_guest_keyid_free(int keyid)
ida_free(&tdx_guest_keyid_pool, keyid);
}

+#define TDX_MD_MAP(_fid, _ptr) \
+ { .fid = MD_FIELD_ID_##_fid, \
+ .ptr = (_ptr), }
+
+struct tdx_md_map {
+ u64 fid;
+ void *ptr;
+};
+
+static size_t tdx_md_element_size(u64 fid)
+{
+ switch (TDX_MD_ELEMENT_SIZE_CODE(fid)) {
+ case TDX_MD_ELEMENT_SIZE_8BITS:
+ return 1;
+ case TDX_MD_ELEMENT_SIZE_16BITS:
+ return 2;
+ case TDX_MD_ELEMENT_SIZE_32BITS:
+ return 4;
+ case TDX_MD_ELEMENT_SIZE_64BITS:
+ return 8;
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+}
+
+static int __used tdx_md_read(struct tdx_md_map *maps, int nr_maps)
+{
+ struct tdx_md_map *m;
+ int ret, i;
+ u64 tmp;
+
+ for (i = 0; i < nr_maps; i++) {
+ m = &maps[i];
+ ret = tdx_sys_metadata_field_read(m->fid, &tmp);
+ if (ret)
+ return ret;
+
+ memcpy(m->ptr, &tmp, tdx_md_element_size(m->fid));
+ }
+
+ return 0;
+}
+
static int __init tdx_module_setup(void)
{
int ret;
--
2.25.1