[v18,019/121] KVM: TDX: Add helper function to read TDX metadata in array

Commit Message

Isaku Yamahata Jan. 22, 2024, 11:52 p.m. UTC

From: Isaku Yamahata <[e-mail]>

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 <[e-mail]>
---
v18:
- newly added
---
 arch/x86/kvm/vmx/tdx.c | 45 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

Patch

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index ee9d6a687d93..1608bdf2381d 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
@@ -40,6 +41,50 @@  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;
+	}
+}
+
+int 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;