linux-kernel - [PATCH v4 22/36] x86/bugs: Add attack vector controls for taa

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: <20250310164023.779191-23-david.kaplan@amd.com>
Date: Mon, 10 Mar 2025 11:40:09 -0500
From: David Kaplan <david.kaplan@....com>
To: Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>,
	Peter Zijlstra <peterz@...radead.org>, Josh Poimboeuf <jpoimboe@...nel.org>,
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, Ingo Molnar
	<mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>, "H . Peter Anvin" <hpa@...or.com>
CC: <linux-kernel@...r.kernel.org>, Brendan Jackman <jackmanb@...gle.com>,
	Derek Manwaring <derekmn@...zon.com>
Subject: [PATCH v4 22/36] x86/bugs: Add attack vector controls for taa

Use attack vector controls to determine if taa mitigation is required.

Signed-off-by: David Kaplan <david.kaplan@....com>
---
 arch/x86/kernel/cpu/bugs.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 197ef9f2cbce..56d3bf343d1f 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -500,12 +500,13 @@ static void __init taa_select_mitigation(void)
 		return;
 	}
 
-	if (cpu_mitigations_off())
-		taa_mitigation = TAA_MITIGATION_OFF;
-
 	/* Microcode will be checked in taa_update_mitigation(). */
-	if (taa_mitigation == TAA_MITIGATION_AUTO)
-		taa_mitigation = TAA_MITIGATION_VERW;
+	if (taa_mitigation == TAA_MITIGATION_AUTO) {
+		if (should_mitigate_vuln(X86_BUG_TAA))
+			taa_mitigation = TAA_MITIGATION_VERW;
+		else
+			taa_mitigation = TAA_MITIGATION_OFF;
+	}
 
 	if (taa_mitigation != TAA_MITIGATION_OFF)
 		verw_mitigation_selected = true;
@@ -513,7 +514,7 @@ static void __init taa_select_mitigation(void)
 
 static void __init taa_update_mitigation(void)
 {
-	if (!taa_vulnerable() || cpu_mitigations_off())
+	if (!taa_vulnerable())
 		return;
 
 	if (verw_mitigation_selected)
@@ -554,7 +555,7 @@ static void __init taa_apply_mitigation(void)
 		 */
 		setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);
 
-		if (taa_nosmt || cpu_mitigations_auto_nosmt())
+		if (taa_nosmt || smt_mitigations == SMT_MITIGATIONS_ON)
 			cpu_smt_disable(false);
 	}
 }
-- 
2.34.1