linux-kernel - [PATCH v3 15/26] x86/virt/seamldr: Abort updates if errors occurred midway

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260123145645.90444-16-chao.gao@intel.com>
Date: Fri, 23 Jan 2026 06:55:23 -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 15/26] x86/virt/seamldr: Abort updates if errors occurred midway

The TDX Module update process has multiple stages, each of which may
encounter failures.

The current state machine of updates proceeds to the next stage
regardless of errors. But continuing updates when errors occur midway
is pointless.

If a CPU encounters an error, abort the update by setting a flag and
exiting the execution loop. Note that this CPU doesn't acknowledge the
current stage. This will keep all other CPUs in the current stage until
they see the flag and exit the loop as well.

Signed-off-by: Chao Gao <chao.gao@...el.com>
Tested-by: Farrah Chen <farrah.chen@...el.com>
---
v3:
 - Instead of fast-forward to the final stage, exit the execution loop
   directly.
---
 arch/x86/virt/vmx/tdx/seamldr.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
index 06080c648b02..a13d526b38a7 100644
--- a/arch/x86/virt/vmx/tdx/seamldr.c
+++ b/arch/x86/virt/vmx/tdx/seamldr.c
@@ -239,6 +239,7 @@ enum tdp_state {
 static struct {
 	enum tdp_state state;
 	atomic_t thread_ack;
+	atomic_t failed;
 } tdp_data;
 
 static void set_target_state(enum tdp_state state)
@@ -277,12 +278,16 @@ static int do_seamldr_install_module(void *params)
 			default:
 				break;
 			}
-			ack_state();
+
+			if (ret)
+				atomic_inc(&tdp_data.failed);
+			else
+				ack_state();
 		} else {
 			touch_nmi_watchdog();
 			rcu_momentary_eqs();
 		}
-	} while (curstate != TDP_DONE);
+	} while (curstate != TDP_DONE && !atomic_read(&tdp_data.failed));
 
 	return ret;
 }
@@ -323,6 +328,7 @@ int seamldr_install_module(const u8 *data, u32 size)
 		return -EBUSY;
 	}
 
+	atomic_set(&tdp_data.failed, 0);
 	set_target_state(TDP_START + 1);
 	ret = stop_machine_cpuslocked(do_seamldr_install_module, params, cpu_online_mask);
 	if (ret)
-- 
2.47.3