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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by DS2PEPF0000343E.mail.protection.outlook.com (10.167.18.41) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8655.12 via Frontend Transport; Fri, 18 Apr 2025 16:17:43 +0000 Received: from tiny.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 18 Apr 2025 11:17:39 -0500 From: David Kaplan To: Thomas Gleixner , Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Pawan Gupta , Ingo Molnar , Dave Hansen , , "H . Peter Anvin" CC: Subject: [PATCH v5 15/16] x86/bugs: Restructure L1TF mitigation Date: Fri, 18 Apr 2025 11:17:20 -0500 Message-ID: <20250418161721.1855190-16-david.kaplan@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250418161721.1855190-1-david.kaplan@amd.com> References: <20250418161721.1855190-1-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: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS2PEPF0000343E:EE_|IA1PR12MB7614:EE_ X-MS-Office365-Filtering-Correlation-Id: e57001c0-1d57-416a-7d2e-08dd7e948ca2 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|36860700013|7416014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?QGvDEPCc8kPktOWDJiRVpkxKBaJkxsv7JfYWLHqjeoR7ttx+bhfAlDq9dE0V?= =?us-ascii?Q?LoF47eBbGhr6Vd6nvdoUyWVSdNvBHUNCZNefFdjCxnoeIZrQ6jlG/oSj0iyw?= =?us-ascii?Q?fHhuUY29wcoOcZRvcJyVUC8UGV+IWr74NyKM/RUF5j3iAg8JYYpMKQ6IzrvZ?= =?us-ascii?Q?QfWKEQGpLrxGbCZN/1du68f1FVX+XnwvWFs486aYhqAw/tSst6yIgWU0wdZd?= =?us-ascii?Q?Ch+jAhQmWtwTfLs4qgCiYRF8PolF3Pkke7MYDP3Ix+djayg9WnUx3v5tDIUz?= =?us-ascii?Q?8aav4l0+R63Xg0CFJR21KrJA13vw3qZiUxbKheA/PfCRWHnZfPmBzIhVd2OQ?= =?us-ascii?Q?xNgNw3GltzHBI0GR5QxarLg83lo7TwWw48Zj8VybGvw7o82CDKeDIX1aGNbK?= =?us-ascii?Q?AONUJ4QHBM0JcTds3Yd2QPaUnwFQ7XPNWImaNisZu0OgkZ2Zsv/E+Pb1ti+7?= =?us-ascii?Q?hmvMfd8IgPiIgl+RGl2wX84tbOEftBDDDfrRhWJzSfGJjNsKaaZU0Ze8GRE+?= =?us-ascii?Q?w0h9gW9fN6sl1cxqHGQ7jFrH3fhrjXkvpaAw3fz4WH9k5YJgptY34UrJ2HLo?= =?us-ascii?Q?PdoQQ1/x4x0FXtvG+d1fOn6UpKWR0ReIQmLi1WAZ/n27c26FdbCHaCwdWIkX?= =?us-ascii?Q?pYWBtDrHP4ptCP5594i1VADxRTcEq69I5zr/Ey6+aCSbVSXD9SGvWqNF4koD?= =?us-ascii?Q?a+AiChayA2ngPMwN4UrgRit5xAqu37+i9uc9rbAppaFd6NUgucf8EIuNWuQ4?= =?us-ascii?Q?dvliHdcXhevF18O7vBHxsN1yK4lBQNKV0yiBTzty/5Wh8XBQeZrD2bAyeAvv?= =?us-ascii?Q?Zg6sM+rtH6NiwPksC0GO1Yej6fl4nPbB62ZGnHFLVgNB00LbyxhkAL7mRY/2?= =?us-ascii?Q?MRlLBkUai/RVuMHt34X1SlOtQmpfUnOZpjMoV2iKxfk1sM3+xzYdM0sBqfgH?= =?us-ascii?Q?32L8HZbuQ0UI1xQ6Il9daNm7KytV3c65eyXzaEaUldzEMP4E3k0Eg+wpSGUd?= =?us-ascii?Q?YFCLB/ViPOt+CvZMEmKIY8+o1erefTl4ELztnpVd8hI+aFLDXD4tfwnaQk4b?= =?us-ascii?Q?B+K3H4Zf2AHmruJ2rlapnvB4vaJrsU7UDbKthS/x2pRYIvZKk92zacdrtV/p?= =?us-ascii?Q?vwuyRkkYbwTD6CjKLI9uwh3FK+9B4LlfkKokbbUeG5UeGG+DkI3r86+Sg+e0?= =?us-ascii?Q?n18Flu37uGPmNveENxt5NCTbOSdWPK+FyieFQoLrVZuKSgC8EiGCxfdtipsL?= =?us-ascii?Q?Kwcazp4pNiF/Ig6+txg04erEDKrX8CQHWsR6rUHBOUA7zPzZQ9PxpzRJI4WV?= =?us-ascii?Q?J+r/Yzlua6ByGKCnEfUgtspR9KpbMVs4nFiWUEvP+aoT6r77WwrbHB/ol2MD?= =?us-ascii?Q?rpKem2xytfeDUdd4G3IkZlb0185pnIul9RAntTOwBP1mXVJhGb7MCIfTFVXL?= =?us-ascii?Q?j3gbPmgq+YilnllPB6vaxGYoVug9Bdep68xMwheb1GFGoxdUCYAf1TYfS0y1?= =?us-ascii?Q?znv6sdHihsOZWE6vbMKBjPhMLHMmhBKEjQGn?= 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)(1800799024)(376014)(36860700013)(7416014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Apr 2025 16:17:43.5364 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e57001c0-1d57-416a-7d2e-08dd7e948ca2 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: DS2PEPF0000343E.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB7614 Content-Type: text/plain; charset="utf-8" Restructure L1TF to use select/apply functions to create consistent vulnerability handling. Define new AUTO mitigation for L1TF. Signed-off-by: David Kaplan --- arch/x86/include/asm/processor.h | 1 + arch/x86/kernel/cpu/bugs.c | 25 +++++++++++++++++++------ arch/x86/kvm/vmx/vmx.c | 2 ++ 3 files changed, 22 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/proces= sor.h index eaa7214d6953..62705783ca3c 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -735,6 +735,7 @@ void store_cpu_caps(struct cpuinfo_x86 *info); =20 enum l1tf_mitigations { L1TF_MITIGATION_OFF, + L1TF_MITIGATION_AUTO, L1TF_MITIGATION_FLUSH_NOWARN, L1TF_MITIGATION_FLUSH, L1TF_MITIGATION_FLUSH_NOSMT, diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e526d06171cd..5f718537ba70 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -67,6 +67,7 @@ static void __init spectre_v2_user_apply_mitigation(void); static void __init ssb_select_mitigation(void); static void __init ssb_apply_mitigation(void); static void __init l1tf_select_mitigation(void); +static void __init l1tf_apply_mitigation(void); static void __init mds_select_mitigation(void); static void __init mds_update_mitigation(void); static void __init mds_apply_mitigation(void); @@ -243,6 +244,7 @@ void __init cpu_select_mitigations(void) retbleed_apply_mitigation(); spectre_v2_user_apply_mitigation(); ssb_apply_mitigation(); + l1tf_apply_mitigation(); mds_apply_mitigation(); taa_apply_mitigation(); mmio_apply_mitigation(); @@ -2543,7 +2545,7 @@ EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation); =20 /* Default mitigation for L1TF-affected CPUs */ enum l1tf_mitigations l1tf_mitigation __ro_after_init =3D - IS_ENABLED(CONFIG_MITIGATION_L1TF) ? L1TF_MITIGATION_FLUSH : L1TF_MITIGAT= ION_OFF; + IS_ENABLED(CONFIG_MITIGATION_L1TF) ? L1TF_MITIGATION_AUTO : L1TF_MITIGATI= ON_OFF; #if IS_ENABLED(CONFIG_KVM_INTEL) EXPORT_SYMBOL_GPL(l1tf_mitigation); #endif @@ -2590,23 +2592,34 @@ 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()) { + l1tf_mitigation =3D L1TF_MITIGATION_OFF; + return; + } + + 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; + } +} + +static void __init l1tf_apply_mitigation(void) { u64 half_pa; =20 if (!boot_cpu_has_bug(X86_BUG_L1TF)) return; =20 - if (cpu_mitigations_off()) - l1tf_mitigation =3D L1TF_MITIGATION_OFF; - else if (cpu_mitigations_auto_nosmt()) - l1tf_mitigation =3D L1TF_MITIGATION_FLUSH_NOSMT; - override_cache_bits(&boot_cpu_data); =20 switch (l1tf_mitigation) { case L1TF_MITIGATION_OFF: case L1TF_MITIGATION_FLUSH_NOWARN: case L1TF_MITIGATION_FLUSH: + case L1TF_MITIGATION_AUTO: break; case L1TF_MITIGATION_FLUSH_NOSMT: case L1TF_MITIGATION_FULL: diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 1547bfacd40f..1b2a783f9ad9 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -273,6 +273,7 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state= l1tf) case L1TF_MITIGATION_OFF: l1tf =3D VMENTER_L1D_FLUSH_NEVER; break; + case L1TF_MITIGATION_AUTO: case L1TF_MITIGATION_FLUSH_NOWARN: case L1TF_MITIGATION_FLUSH: case L1TF_MITIGATION_FLUSH_NOSMT: @@ -7704,6 +7705,7 @@ int vmx_vm_init(struct kvm *kvm) case L1TF_MITIGATION_FLUSH_NOWARN: /* 'I explicitly don't care' is set */ break; + case L1TF_MITIGATION_AUTO: case L1TF_MITIGATION_FLUSH: case L1TF_MITIGATION_FLUSH_NOSMT: case L1TF_MITIGATION_FULL: --=20 2.34.1