All pieces of TDX module runtime updates are in place. Enable it if it
is supported.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com>
Reviewed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 arch/x86/include/asm/tdx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 282cb0e08b8e..c848483d815f 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -34,6 +34,7 @@
 #define TDX_UPDATE_COMPAT_SENSITIVE	0x8000051200000000ULL
 
 /* Bit definitions of TDX_FEATURES0 metadata field */
+#define TDX_FEATURES0_TD_PRESERVING	BIT_ULL(1)
 #define TDX_FEATURES0_NO_RBP_MOD	BIT_ULL(18)
 
 #ifndef __ASSEMBLER__
@@ -114,8 +115,7 @@ const struct tdx_sys_info *tdx_get_sysinfo(void);
 
 static inline bool tdx_supports_runtime_update(const struct tdx_sys_info *sysinfo)
 {
-	/* To be enabled when kernel is ready. */
-	return false;
+	return sysinfo->features.tdx_features0 & TDX_FEATURES0_TD_PRESERVING;
 }
 
 int tdx_guest_keyid_alloc(void);
-- 
2.52.0