diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 3e6dbd2199cfc..2f27ae1e2c6bf 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -816,6 +816,9 @@ void __init tdx_early_init(void)
 
 	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
 
+	/* TSC is the only reliable clock in TDX guest */
+	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+
 	cc_vendor = CC_VENDOR_INTEL;
 	tdx_parse_tdinfo(&cc_mask);
 	cc_set_mask(cc_mask);