linux-kernel - [tip: x86/bugs] x86/bugs: Add attack vector controls for GDS

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Message-ID: <175225017889.406.13837449048056339085.tip-bot2@tip-bot2>
Date: Fri, 11 Jul 2025 16:09:38 -0000
From: "tip-bot2 for David Kaplan" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: David Kaplan <david.kaplan@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/bugs] x86/bugs: Add attack vector controls for GDS

The following commit has been merged into the x86/bugs branch of tip:

Commit-ID:     8c7261abcb7ad1df493773fd52ff3ddce37a25e6
Gitweb:        https://git.kernel.org/tip/8c7261abcb7ad1df493773fd52ff3ddce37a25e6
Author:        David Kaplan <david.kaplan@....com>
AuthorDate:    Mon, 07 Jul 2025 13:33:05 -05:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Fri, 11 Jul 2025 17:56:41 +02:00

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>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/20250707183316.1349127-11-david.kaplan@amd.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 de0b5ef..e9227e4 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1030,12 +1030,15 @@ 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)) {