linux-kernel - [PATCH v5 10/20] x86/bugs: Add attack vector controls for GDS

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Message-ID: <20250509162839.3057217-11-david.kaplan@amd.com>
Date: Fri, 9 May 2025 11:28:29 -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 10/20] x86/bugs: Add attack vector controls for GDS

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

Signed-off-by: David Kaplan <david.kaplan@....com>
---
 arch/x86/kernel/cpu/bugs.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 237ef8d0980a..659455c5b38f 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1008,12 +1008,15 @@ static void __init gds_select_mitigation(void)
 		return;
 	}
 
-	if (cpu_mitigations_off())
-		gds_mitigation = GDS_MITIGATION_OFF;
 	/* Will verify below that mitigation _can_ be disabled */
-
-	if (gds_mitigation == GDS_MITIGATION_AUTO)
-		gds_mitigation = GDS_MITIGATION_FULL;
+	if (gds_mitigation == GDS_MITIGATION_AUTO) {
+		if (should_mitigate_vuln(X86_BUG_GDS))
+			gds_mitigation = GDS_MITIGATION_FULL;
+		else {
+			gds_mitigation = GDS_MITIGATION_OFF;
+			return;
+		}
+	}
 
 	/* No microcode */
 	if (!(x86_arch_cap_msr & ARCH_CAP_GDS_CTRL)) {
-- 
2.34.1