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Peter Anvin" CC: , Brendan Jackman , Derek Manwaring Subject: [PATCH v4 32/36] x86/bugs: Add attack vector controls for l1tf Date: Mon, 10 Mar 2025 11:40:19 -0500 Message-ID: <20250310164023.779191-33-david.kaplan@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250310164023.779191-1-david.kaplan@amd.com> References: <20250310164023.779191-1-david.kaplan@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL6PEPF00022574:EE_|PH7PR12MB7209:EE_ X-MS-Office365-Filtering-Correlation-Id: b8ac744b-26d9-478d-377d-08dd5ff25c24 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|376014|7416014|36860700013|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?rJ7NPGW6uTsWYes48CaLeRcLZx6tqfhgoeyCo+rVwD5KrSTuiazRrwHcf88j?= =?us-ascii?Q?taqUCMAJSui0AxJWIQYaMLu/LtIVfQGerKjPM2T5/B8kS5M54dTx2sSFwc3d?= =?us-ascii?Q?Hw4rQ6ZKVoc0zPtzKIXXZRIjJ0pMQdeOM7/0rSyvxj8o1m7Uael42RAAu8KE?= =?us-ascii?Q?VCGmmIQBzbbSibMfAvPAL5fs4S1dkqEt7EtBIOvmLRU1IkfSFi9vjafger49?= =?us-ascii?Q?YKfW6edRGfeQA5lzdu2CrmDRxX5qIDoz5qA+pDYA492lqNKhvbT5u6TgfYmd?= =?us-ascii?Q?+73r5Vz8x3rLmsLPcrr3nG2TqdDE40ObLHXywAnj4D2AMMzpYc6xIgtcGvTN?= =?us-ascii?Q?/QqL3+cCYWbYC1zfb1L5STlDlc9o8lwp9IzpUHHoErO9LgyK/mK13Qet5u7Q?= =?us-ascii?Q?lGY0jDwIp82WhoLB8JQkSVE2Rt81mJhdroOB1XImdI8u2orCwh9CU6MjlsS9?= =?us-ascii?Q?QFYkDcmzdq2/7G0E1wbX2hbawCBf0DrGX5fU01HkdQ8dmrFOPXMeskjMC5z/?= =?us-ascii?Q?AmTjTpEqZpIu2DfcDGYkeg7gAKk19u/Q9YKa/EgRiCvFCEfNZxVuFXM38vuS?= =?us-ascii?Q?x8ziRO3xd+O2XOoBj7Uw2hmZ6rOKyZ19aMtasktgiptjjr2iYwEnV5eIcliz?= =?us-ascii?Q?GefEcLqS/d5eY44eXdg1idWSpvbFX/xQHlpRl6SXQzdgZh61ljmjDqBtnJQF?= =?us-ascii?Q?1yo5p9vmZYafalpfpdAQObvAmwsiuplU/aV3rSlrWS4rgWSqMl/SUMeKs2z9?= =?us-ascii?Q?2PWMX9PT7CbnGLnszV4NnZCAAD500HEHs+GN97bWX99G12XfRzPeHkZux5r/?= =?us-ascii?Q?nCGm8+gpa8SmfZNdw42LUd3AzV9E57/g2n6YGzqWyenzVPCfdSR0OSGgYjTt?= =?us-ascii?Q?WTPnnHwPJAB5gLDzxy6TWdKqP3ejSsVgFjrdBpYsFiPrGrJUigcnB/sGHd65?= =?us-ascii?Q?sfPO4iJ4rObLKUqGpUS4IMfWfpak2RDKizxpfgA2j5gKO/9lccDxTU4MADuX?= =?us-ascii?Q?MznsLWR+Ab7nWko+Ycf5FzgCxw0r+BcxZy60Bn7DkVuC9tW6qRjDK/MuMgnd?= =?us-ascii?Q?3jTd2vlUb7T8sq8a/7FPsg1t1RakGjsl1VItDWycAxAe7E6kDcYFzUXGzdv8?= =?us-ascii?Q?ohifLB4ifScEDsju6P0puP1YQmt4dCvW4MBvQdeMTNszerjxAHR/3E5KDemH?= =?us-ascii?Q?LNmbJ7JJm3BhkmP/klRguRRDccPHnxBXjYy7KYpbXQ45aTIiw1EjripC0kOe?= =?us-ascii?Q?jqKzDumHucieolJyeeAomNS5vXWKZP/Sn25bZG5tj/CXq7hEvd7qU/umoGmk?= =?us-ascii?Q?9nC99U/IqfC3N3WdSb8HDL9GSeiDcvOkJMJN02LC72NXAYf3OXp9l9T27S4+?= =?us-ascii?Q?ePFu754/6EmFt2fIXF7vsbm2dhtdJtETybh+X47aT6Q+WE6RmOMI1XGUuF8j?= =?us-ascii?Q?wjkpDknp9axs9xWmvP+34RcmqnvixYzP/3vZZttgZ7AYkj7S6XjSjqD0sjcL?= =?us-ascii?Q?3uCZwTMR0a43Fkw=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(376014)(7416014)(36860700013)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Mar 2025 16:41:08.8611 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b8ac744b-26d9-478d-377d-08dd5ff25c24 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BL6PEPF00022574.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB7209 Content-Type: text/plain; charset="utf-8" Use attack vector controls to determine if l1tf mitigation is required. Disable SMT if cross-thread attack vector option is selected. Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e35f7059f6fc..e38529f3022b 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2717,16 +2717,20 @@ static void override_cache_bits(struct cpuinfo_x86 = *c) =20 static void __init l1tf_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_L1TF) || cpu_mitigations_off()) { + if (!boot_cpu_has_bug(X86_BUG_L1TF)) { l1tf_mitigation =3D L1TF_MITIGATION_OFF; return; } =20 if (l1tf_mitigation =3D=3D L1TF_MITIGATION_AUTO) { - if (cpu_mitigations_auto_nosmt()) - l1tf_mitigation =3D L1TF_MITIGATION_FLUSH_NOSMT; - else - l1tf_mitigation =3D L1TF_MITIGATION_FLUSH; + if (!should_mitigate_vuln(X86_BUG_L1TF)) + l1tf_mitigation =3D L1TF_MITIGATION_OFF; + else { + if (smt_mitigations =3D=3D SMT_MITIGATIONS_ON) + l1tf_mitigation =3D L1TF_MITIGATION_FLUSH_NOSMT; + else + l1tf_mitigation =3D L1TF_MITIGATION_FLUSH; + } } } =20 --=20 2.34.1