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Message-ID: <20250509162839.3057217-7-david.kaplan@amd.com>
Date: Fri, 9 May 2025 11:28:25 -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>
Subject: [PATCH v5 06/20] 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 97d152c33e9e..d57132cdbc21 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -516,12 +516,13 @@ 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_clear_cpu_buf_mitigation_selected = true;
@@ -529,7 +530,7 @@ 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_clear_cpu_buf_mitigation_selected)
@@ -570,7 +571,7 @@ 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
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