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Peter Anvin" CC: , Brendan Jackman , Derek Manwaring Subject: [PATCH v4 06/36] x86/bugs: Restructure srbds mitigation Date: Mon, 10 Mar 2025 11:39:53 -0500 Message-ID: <20250310164023.779191-7-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: BL6PEPF00022572:EE_|SN7PR12MB8103:EE_ X-MS-Office365-Filtering-Correlation-Id: b5c1937a-ad34-4a51-075b-08dd5ff24c1b 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?ujm6HRW0hUEKZxKe9HtrRBooR/I6dqaEl/ab4LbET72rG5tvEyaUENp4galJ?= =?us-ascii?Q?1RnHmwZjUTPRKgIC2r+uiy31dhmJBBh/G8mU0wShQoI+sdWmtHfyz0OuQ2Wm?= =?us-ascii?Q?hzT0FuPoSmIkWmDby7xVaiJ73htcLAvK6D+3/zqUmF1laNUphysUyKYRp4P7?= =?us-ascii?Q?50At5HUdGYOG/3Q/YeTuG17hug/Lnk7HM6yErvmk9FUSD0DLS5eIFqQJmRrn?= =?us-ascii?Q?FOyrL05ah6Op+dMXGHYphk5UXwZlpqKkpJT/jfTVxq65rkx/G351JJHtacC0?= =?us-ascii?Q?u88/ePbhLbazNa9jafmcyMh/cR2vbUnLtKfhSzqKuHKXIryeGC9qTWDeNoyD?= =?us-ascii?Q?ZGS0be6vrvTGJ4fhbmv2cS1BMwLSDvBZfDbnori15w+4NPg+0r6o1Fp5twA5?= =?us-ascii?Q?ZVu4QPW2DwjPdCrXDOLqMFBe6a5TCxbw4g8p1YVaZL9FRtS6jkRpuBI2B2QI?= =?us-ascii?Q?8UnTlHqLT4MajqCtSk9D/fs+lbMoR9wMYfJD8JpOG8ITJ5qHBorEXbmmw1Ed?= =?us-ascii?Q?UdxGggB+2uZvz9EUxLbPHryTIBo6RPExdEm3xaai1J3FWmIC1+eDK/TatuoJ?= =?us-ascii?Q?lPzHBYUItSqLNenmQzklpIVIuOatGgrHHAXh1sd5KJ1++Ixy9BOAn2/U4WJQ?= =?us-ascii?Q?gqVQ/Th8wckrJQEXddxpiYZzOQrZklTtYrhIOb24dJUDo91pwnPA23PPcGDg?= =?us-ascii?Q?lsydHV8A72K0BtvSVPfb3KrqGeMv0f/A+hUL+BQWM5nHtYFWiNLjw27MFnvR?= =?us-ascii?Q?JIx3U3dTDDD2ivrOGm7ur7XATE9t6ejt9plJE/1cCop6FzRJblPU6bCbHwrr?= =?us-ascii?Q?L1Nv+a/AMjcCMd/K/2/xz/4fmu9S0yJcpOz4cXUH9lBa4Pv59056Q6xpoLDy?= =?us-ascii?Q?uo8BhLZRLtAePfij79HkqTsgK7Y1zwcQ/PqXQ4OR1cZcYC/c3RueiUFGVlWz?= =?us-ascii?Q?Hnsw6T7+aBZf5P3LQH+qVvivKAz6OhPY0uhNJi7gfa/IKFnMnTpcr5s1i9qS?= =?us-ascii?Q?Y7N2ZS6jnBC4uVQ1Y49ByPBMtISZ7sPY0ysrASW0PXbYzrAB/S6BjPaOP17z?= =?us-ascii?Q?z/BARYvOUpQb7SQpTZkpNGeGHKy0A6QXpxlYwEasIasUzHD7npOLJFwjQbtY?= =?us-ascii?Q?DGTip1dtmVJfU1BPk77odQewPC2j+TcMbQI8TPWFZh+O56/aghOJe/TYKECN?= =?us-ascii?Q?ZQq54gJcn/X3r5PxPZmsYFfKTDtAzyhhGUDOgR/OFTXyRP8Ft26UG51Rj4q1?= =?us-ascii?Q?HgqpmmEfygaPg/SSsaEA1kJ/EouiWvH6Vv5Kbw63+yi1K/0HG31Wyh8SRV0y?= =?us-ascii?Q?ZnXPWrdJ51Is4CUShjAJ8diZMbuXYT1o9B3m85QqQER3Vzpb9EoSQOWyeW/U?= =?us-ascii?Q?kAdvh9lgFZQc2bNT0Cx2yZVcdzDURtu2fThjSS6jpFVZxC0uMYpn97HLVL9q?= =?us-ascii?Q?CuXKicgEXWjk3WE+/TPkV77pXf9yMZk5/ipNELHiux2XFi5H2D0PeWvXLEm6?= =?us-ascii?Q?bPyaFK2ANrldnF8=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 16:40:41.9573 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b5c1937a-ad34-4a51-075b-08dd5ff24c1b 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: BL6PEPF00022572.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8103 Content-Type: text/plain; charset="utf-8" Restructure srbds to use select/apply functions to create consistent vulnerability handling. Define new AUTO mitigation for SRBDS. Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 841ab123a180..fd04de518fd0 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -72,6 +72,7 @@ static void __init rfds_select_mitigation(void); static void __init rfds_update_mitigation(void); static void __init rfds_apply_mitigation(void); static void __init srbds_select_mitigation(void); +static void __init srbds_apply_mitigation(void); static void __init l1d_flush_select_mitigation(void); static void __init srso_select_mitigation(void); static void __init gds_select_mitigation(void); @@ -222,6 +223,7 @@ void __init cpu_select_mitigations(void) taa_apply_mitigation(); mmio_apply_mitigation(); rfds_apply_mitigation(); + srbds_apply_mitigation(); } =20 /* @@ -680,6 +682,7 @@ early_param("reg_file_data_sampling", rfds_parse_cmdlin= e); =20 enum srbds_mitigations { SRBDS_MITIGATION_OFF, + SRBDS_MITIGATION_AUTO, SRBDS_MITIGATION_UCODE_NEEDED, SRBDS_MITIGATION_FULL, SRBDS_MITIGATION_TSX_OFF, @@ -687,7 +690,7 @@ enum srbds_mitigations { }; =20 static enum srbds_mitigations srbds_mitigation __ro_after_init =3D - IS_ENABLED(CONFIG_MITIGATION_SRBDS) ? SRBDS_MITIGATION_FULL : SRBDS_MITIG= ATION_OFF; + IS_ENABLED(CONFIG_MITIGATION_SRBDS) ? SRBDS_MITIGATION_AUTO : SRBDS_MITIG= ATION_OFF; =20 static const char * const srbds_strings[] =3D { [SRBDS_MITIGATION_OFF] =3D "Vulnerable", @@ -738,8 +741,13 @@ void update_srbds_msr(void) =20 static void __init srbds_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_SRBDS)) + if (!boot_cpu_has_bug(X86_BUG_SRBDS) || cpu_mitigations_off()) { + srbds_mitigation =3D SRBDS_MITIGATION_OFF; return; + } + + if (srbds_mitigation =3D=3D SRBDS_MITIGATION_AUTO) + srbds_mitigation =3D SRBDS_MITIGATION_FULL; =20 /* * Check to see if this is one of the MDS_NO systems supporting TSX that @@ -753,13 +761,17 @@ static void __init srbds_select_mitigation(void) srbds_mitigation =3D SRBDS_MITIGATION_HYPERVISOR; else if (!boot_cpu_has(X86_FEATURE_SRBDS_CTRL)) srbds_mitigation =3D SRBDS_MITIGATION_UCODE_NEEDED; - else if (cpu_mitigations_off() || srbds_off) + else if (srbds_off) srbds_mitigation =3D SRBDS_MITIGATION_OFF; =20 - update_srbds_msr(); pr_info("%s\n", srbds_strings[srbds_mitigation]); } =20 +static void __init srbds_apply_mitigation(void) +{ + update_srbds_msr(); +} + static int __init srbds_parse_cmdline(char *str) { if (!str) --=20 2.34.1