linux-kernel - [PATCH v3 18/26] x86/virt/seamldr: Log TDX Module update failures

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Message-ID: <20260123145645.90444-19-chao.gao@intel.com>
Date: Fri, 23 Jan 2026 06:55:26 -0800
From: Chao Gao <chao.gao@...el.com>
To: linux-coco@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org,
	x86@...nel.org
Cc: reinette.chatre@...el.com,
	ira.weiny@...el.com,
	kai.huang@...el.com,
	dan.j.williams@...el.com,
	yilun.xu@...ux.intel.com,
	sagis@...gle.com,
	vannapurve@...gle.com,
	paulmck@...nel.org,
	nik.borisov@...e.com,
	zhenzhong.duan@...el.com,
	seanjc@...gle.com,
	rick.p.edgecombe@...el.com,
	kas@...nel.org,
	dave.hansen@...ux.intel.com,
	vishal.l.verma@...el.com,
	Chao Gao <chao.gao@...el.com>,
	Farrah Chen <farrah.chen@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v3 18/26] x86/virt/seamldr: Log TDX Module update failures

If failures occur after the TDX Module has been successfully shut down,
they are unrecoverable. The kernel cannot restore the previous TDX
Module to a running state. All subsequent SEAMCALLs to the TDX Module
will fail, so TDs cannot continue to run.

Log a message to clarify that SEAMCALL errors are expected in this case.

To prevent TDX Module update failures, admins are encouraged to use the
user space tool [1] that will perform compatibility and integrity checks
that guarantee TDX Module update success.

Signed-off-by: Chao Gao <chao.gao@...el.com>
Tested-by: Farrah Chen <farrah.chen@...el.com>
Link: https://github.com/intel/tdx-module-binaries/blob/main/version_select_and_load.py # [1]
---
v3:
 - Rephrase the changelog to eliminate the confusing uses of 'i.e.' and 'e.g.'
   [Dave/Yilun]
---
 arch/x86/virt/vmx/tdx/seamldr.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
index 76f404d1115c..b497fa72ebb6 100644
--- a/arch/x86/virt/vmx/tdx/seamldr.c
+++ b/arch/x86/virt/vmx/tdx/seamldr.c
@@ -260,6 +260,14 @@ static void ack_state(void)
 		set_target_state(tdp_data.state + 1);
 }
 
+static void print_update_failure_message(void)
+{
+	static atomic_t printed = ATOMIC_INIT(0);
+
+	if (atomic_inc_return(&printed) == 1)
+		pr_err("update failed, SEAMCALLs will report failure until TDs killed\n");
+}
+
 /*
  * See multi_cpu_stop() from where this multi-cpu state-machine was
  * adopted, and the rationale for touch_nmi_watchdog()
@@ -289,10 +297,13 @@ static int do_seamldr_install_module(void *params)
 				break;
 			}
 
-			if (ret)
+			if (ret) {
 				atomic_inc(&tdp_data.failed);
-			else
+				if (curstate > TDP_SHUTDOWN)
+					print_update_failure_message();
+			} else {
 				ack_state();
+			}
 		} else {
 			touch_nmi_watchdog();
 			rcu_momentary_eqs();
-- 
2.47.3