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Peter Anvin" CC: , Brendan Jackman , Derek Manwaring Subject: [PATCH v4 24/36] x86/bugs: Add attack vector controls for rfds Date: Mon, 10 Mar 2025 11:40:11 -0500 Message-ID: <20250310164023.779191-25-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_|MN0PR12MB5977:EE_ X-MS-Office365-Filtering-Correlation-Id: 653ee758-0e31-401b-d2d2-08dd5ff2572f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|36860700013|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?7/Chf8SfjmYkl+pE5gXf9xHlb3lfu+wFyBG71g8ZyTtNFpMyGgy1Yuz3m50u?= =?us-ascii?Q?rf6I3E8VEajRBZsCAvaibozg9ycdbVPEkVZ/jQZjqK7O1SWe5eMLVo5tSZF9?= =?us-ascii?Q?0mky8dDx3jTn3qLXiLa1wRSQq1e6O/FQ3P3RiMNowFA8CeCW8mcka1fKa4xE?= =?us-ascii?Q?kQg8kSuMj3GL4fNbLUWK+DRNdicwQO+7Tr3z9Km5TZWji/A7CXE3gT2GfR0p?= =?us-ascii?Q?jbEO0+mATrXfBJK6acX5FG1JFPTAeUTv6sB9uHXpAXIiXSV49BaytWtn76JP?= =?us-ascii?Q?+7lyYsEkAy6nYatulhc4hqCzO2yNiKrcFPceet1LmdIERRLTSaifO2QCZ8m5?= =?us-ascii?Q?rSbpkmsnXxesqMNQ6rvYA1svnAR1/T+ODuqDyUPdB2CvN9+nKaeCuvuGyMXf?= =?us-ascii?Q?ZxWO/HZpPRWYfKW1MN8EQ3BfnZThdwNDRAxDguxnEp24jldpl6cLfnDuodB9?= =?us-ascii?Q?exlu63LJEx1OHTQ/1kzs0QZHtdF2YARGhpEW9elq+xs5+YWzBhKtWHrQttZw?= =?us-ascii?Q?LH36PzSzR7ObBNzkLnZLPEVAstl4QAVZYIjQIXC/5IwVIG7uthcYATpN0w4F?= =?us-ascii?Q?gBXlgBnza7oy18BHWXwfsO4OO47vNBP7Wqt8oWceZ6jvTFmEgDZAf7C/64bt?= =?us-ascii?Q?mySmV4RKdJrpqloLitc2MaU7u6BOlCzB8nLRMNyYG6VUybTXDlvrmfV9hc4z?= =?us-ascii?Q?g+FqdsmXV5UU5nirtBLuFP64W1NSHMfbMGx84ezgcxlvo5YxdEuymiPnjGti?= =?us-ascii?Q?NEHmzs6iZ83oB6VUQ/NZUBrIsfuJZ+URqjobRcpu/KEj0TKBuwMnVH7D1ren?= =?us-ascii?Q?OT0gSs4kAjJMd1oxxAu1xgb1IR7iymQkmQU1VT4JQ5nZZk7iKkqm951xRa2b?= =?us-ascii?Q?X/OpC96+pwsJFPaLm3RoNxV3rI9etHAmiWdKvwkFZNqsJtjtU6gm2kO725nO?= =?us-ascii?Q?q3sFi17lH34LVuy5RJsp8cLqyS8mHGJ6IKbRk7uBp8h/426En56v7mq6trV8?= =?us-ascii?Q?wzvKKKmt4KIQPchTdlAyNXGMmwKyAIij6r+uNqq6MJQdBGNmi0ebKpnb5T6F?= =?us-ascii?Q?skWpNcMYlxjidrXtx4HkB+C+69Of8dA2usRkkZxKw6gQjRaSQ8WVPbI95otG?= =?us-ascii?Q?CqhbQBDlUq/Iep0fAZWroRTT0CqNeJBYQ7EgLGn+At281k8PHDxJd6oBe3IQ?= =?us-ascii?Q?ftY6QJpmzm46Ufod29GhP918iagwq/s21JP4t9D9iNuVZc3B9lTqKFsS3pw1?= =?us-ascii?Q?QzaU3iUmFvAIbHSvkKcLNVmSZZNtHpGO4sWszH9ycOrt/5xNMJk3eDEp+mDs?= =?us-ascii?Q?lkMmJfrluFZYg/tCf+x1KYpMgbo3MW97Qys2L3zZrkkl1R73RHtXyt9Xa5qL?= =?us-ascii?Q?xXyEqHB7EDFlOHUBQU1O3u98+zeEzGLMV21idPaCx3OTpev6xfJ2zyAmOYHI?= =?us-ascii?Q?8S0EUW1dGjexNgTE0xI9NJnY5lHSjkUOhV0CYSfeev7AOwN4WZvZAf38XRwp?= =?us-ascii?Q?cPbgFFfY65fQk4k=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)(7416014)(376014)(1800799024)(36860700013)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Mar 2025 16:41:00.5485 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 653ee758-0e31-401b-d2d2-08dd5ff2572f 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: MN0PR12MB5977 Content-Type: text/plain; charset="utf-8" Use attack vector controls to determine if rfds mitigation is required. Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index ba7c2a1ea98f..32f850c80b86 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -712,13 +712,20 @@ static bool __init rfds_has_ucode(void) =20 static void __init rfds_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_RFDS) || cpu_mitigations_off()) { + if (!boot_cpu_has_bug(X86_BUG_RFDS)) { rfds_mitigation =3D RFDS_MITIGATION_OFF; return; } =20 - if (rfds_mitigation =3D=3D RFDS_MITIGATION_AUTO) - rfds_mitigation =3D RFDS_MITIGATION_VERW; + if (rfds_mitigation =3D=3D RFDS_MITIGATION_AUTO) { + if (should_mitigate_vuln(X86_BUG_RFDS)) + rfds_mitigation =3D RFDS_MITIGATION_VERW; + else + rfds_mitigation =3D RFDS_MITIGATION_OFF; + } + + if (rfds_mitigation =3D=3D RFDS_MITIGATION_OFF) + return; =20 if (rfds_has_ucode()) verw_mitigation_selected =3D true; @@ -726,7 +733,7 @@ static void __init rfds_select_mitigation(void) =20 static void __init rfds_update_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_RFDS) || cpu_mitigations_off()) + if (!boot_cpu_has_bug(X86_BUG_RFDS)) return; =20 if (verw_mitigation_selected) --=20 2.34.1