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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 16:17:40 +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 11:17:38 -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 12/16] x86/bugs: Restructure BHI mitigation Date: Fri, 18 Apr 2025 11:17:17 -0500 Message-ID: <20250418161721.1855190-13-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_|IA1PR12MB6209:EE_ X-MS-Office365-Filtering-Correlation-Id: ce71687a-5f58-424d-91cc-08dd7e948af7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700013|376014|1800799024|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?sonGZiJVoAdWP3eqBgGXC8bIoTDX7ni6WQVHqPmAR+5zAjVeAYmRT694vq38?= =?us-ascii?Q?tE8Vd1wU+JqfzT+2dPawb/iehz9WXN8FGTE0t8HlgbyTPPAncPXfpM9/2fcu?= =?us-ascii?Q?MvPeQ53ECWeQ3I3ZZP+rS6A7tfobEDZIRNqEOF91Pthng6Yr8jT3Q9k98kcW?= =?us-ascii?Q?r6vnjhwJaXI8EM6SEoBKxp9q1C/KfYbr2Ww4V4KuiU111Zkc1FrB/cws8X4r?= =?us-ascii?Q?NKPEmNnsSj+TOgeY93jBdYh8lktqmI/R6kRyft7WXHx5p3Aqz3vKIhkYaqEy?= =?us-ascii?Q?Q2hBPfES+4JuZuCde6A/TADBqmpJTnHEg+BEAMhQi2Lbt090paWKh6M2PwRC?= =?us-ascii?Q?GzJFy5YgzQSsirbJDNo9Q1fo8Sk91aR03RAAcyamnxkzDsPLpLdvTWF1dznv?= =?us-ascii?Q?vudyKlyj8qfndIFni4y5EXqSnxTbfvZmqRUXJQckiH4377VB+pte+GRpO8s1?= =?us-ascii?Q?FooGC1aYxNMg9XFkUK0byo1XPKSVfK7L75W1X8YS4MYKj3pgcd9jqlGIBWwG?= =?us-ascii?Q?jfkamNX6hezAnYUP0iR0NEyiyF7bpLSo9YorFue9AKeK2E+HPaN/Z+q62cfc?= =?us-ascii?Q?I5ZRPNmmH0zWSc2so8E8skdc/9adDylAQY5uSnhJJUG2E9AoPd7N0SeRuiVP?= =?us-ascii?Q?oY3eSOo2dZiPnptL55rjzOLURNz5YrQEuwEB7xwpeGCUdJREOZyIc4fuDZ+4?= =?us-ascii?Q?qWqBzkixFwmdPkf971ddZs6D/iJoDESLICYPzp//53lXjdeHbfj+WHSWIDy8?= =?us-ascii?Q?ruJE+X/+tdVR0xSYjla3cIT/CrQKv92QllnbDBsfTAFsolMXHE4FJGNx8fSq?= =?us-ascii?Q?y7hzS6xIvAtuOpDUPZQBEPEtFjhA8iHs/mJOW++9pRV15jEYer1ei731PtHU?= =?us-ascii?Q?siqEAKh8OtrNiWq0OweyO05kUgPLILTg1dtVfcP/Np0RkCipCj6JuAulgPGE?= =?us-ascii?Q?g4VJfPgblN9aeNJauHZM0eWoG0HwgMIJDl8qjIq3TPkHRfzGosKlJBlHfaO2?= =?us-ascii?Q?YFPWpPjsOT70ynDF2ocL4/aVYvcwImkqTwlQfsaDHe7AIDUNZ/or4yc8lllu?= =?us-ascii?Q?V4g5sMnL6egioe70tyf6et77S1ZjxpQ93uO69uRQIXqexv4TDs4HljkoXA8k?= =?us-ascii?Q?6qEyDOHVgB1lP+b+l8soiBnkuRYvYiwWcztMXbip2yAyj+6xCSeCOuplKw3q?= =?us-ascii?Q?2xdpXt2iM9sS7K6+chFPaneiUyhFWiO2lLuwou3FWGh8qRwJUPmmajCYdOES?= =?us-ascii?Q?y1EkvZiDka5pdgxXv2ValHu+OnVg0IP89M4+mF3rig+J8Ujspa95jpwZ0Npe?= =?us-ascii?Q?c/ACxI9gX+MBeThz2IWfZIh9aGH77aaILyDNYh38os+TfmPYR52B8hslqJAu?= =?us-ascii?Q?QfYtHXDIbgsX5Maa/yG9QMet2lLJ1Q1n/nr3ThFd/Dz8NpBp2URYGb0fS1R3?= =?us-ascii?Q?39RgRsLIGH4pbF0xWUxnVAipB7GR3c2myurCLl9y5eYtZpc8UwZ6rklda+LZ?= =?us-ascii?Q?02JH5OUFs5yNUx/+brrJGEnqIi66CAbuKXMg?= 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)(36860700013)(376014)(1800799024)(7416014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Apr 2025 16:17:40.7377 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ce71687a-5f58-424d-91cc-08dd7e948af7 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: IA1PR12MB6209 Content-Type: text/plain; charset="utf-8" Restructure BHI mitigation to use select/update/apply functions to create consistent vulnerability handling. BHI mitigation was previously selected from within spectre_v2_select_mitigation() and now is selected from cpu_select_mitigation() like with all others. Define new AUTO mitigation for BHI. Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index bb20cfb81015..b7063f58ae88 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -82,6 +82,9 @@ static void __init l1d_flush_select_mitigation(void); static void __init srso_select_mitigation(void); static void __init gds_select_mitigation(void); static void __init gds_apply_mitigation(void); +static void __init bhi_select_mitigation(void); +static void __init bhi_update_mitigation(void); +static void __init bhi_apply_mitigation(void); =20 /* The base value of the SPEC_CTRL MSR without task-specific bits set */ u64 x86_spec_ctrl_base; @@ -208,6 +211,7 @@ void __init cpu_select_mitigations(void) */ srso_select_mitigation(); gds_select_mitigation(); + bhi_select_mitigation(); =20 /* * After mitigations are selected, some may need to update their @@ -223,6 +227,7 @@ void __init cpu_select_mitigations(void) taa_update_mitigation(); mmio_update_mitigation(); rfds_update_mitigation(); + bhi_update_mitigation(); =20 spectre_v1_apply_mitigation(); retbleed_apply_mitigation(); @@ -233,6 +238,7 @@ void __init cpu_select_mitigations(void) rfds_apply_mitigation(); srbds_apply_mitigation(); gds_apply_mitigation(); + bhi_apply_mitigation(); } =20 /* @@ -1792,12 +1798,13 @@ static bool __init spec_ctrl_bhi_dis(void) =20 enum bhi_mitigations { BHI_MITIGATION_OFF, + BHI_MITIGATION_AUTO, BHI_MITIGATION_ON, BHI_MITIGATION_VMEXIT_ONLY, }; =20 static enum bhi_mitigations bhi_mitigation __ro_after_init =3D - IS_ENABLED(CONFIG_MITIGATION_SPECTRE_BHI) ? BHI_MITIGATION_ON : BHI_MITIG= ATION_OFF; + IS_ENABLED(CONFIG_MITIGATION_SPECTRE_BHI) ? BHI_MITIGATION_AUTO : BHI_MIT= IGATION_OFF; =20 static int __init spectre_bhi_parse_cmdline(char *str) { @@ -1818,6 +1825,25 @@ static int __init spectre_bhi_parse_cmdline(char *st= r) early_param("spectre_bhi", spectre_bhi_parse_cmdline); =20 static void __init bhi_select_mitigation(void) +{ + if (!boot_cpu_has(X86_BUG_BHI) || cpu_mitigations_off()) + bhi_mitigation =3D BHI_MITIGATION_OFF; + + if (bhi_mitigation =3D=3D BHI_MITIGATION_AUTO) + bhi_mitigation =3D BHI_MITIGATION_ON; +} + +static void __init bhi_update_mitigation(void) +{ + if (spectre_v2_cmd =3D=3D SPECTRE_V2_CMD_NONE) + bhi_mitigation =3D BHI_MITIGATION_OFF; + + if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2) && + spectre_v2_cmd =3D=3D SPECTRE_V2_CMD_AUTO) + bhi_mitigation =3D BHI_MITIGATION_OFF; +} + +static void __init bhi_apply_mitigation(void) { if (bhi_mitigation =3D=3D BHI_MITIGATION_OFF) return; @@ -1959,9 +1985,6 @@ static void __init spectre_v2_select_mitigation(void) mode =3D=3D SPECTRE_V2_RETPOLINE) spec_ctrl_disable_kernel_rrsba(); =20 - if (boot_cpu_has(X86_BUG_BHI)) - bhi_select_mitigation(); - spectre_v2_enabled =3D mode; pr_info("%s\n", spectre_v2_strings[mode]); =20 --=20 2.34.1