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Peter Anvin" , "Peter Zijlstra" , Pavan Kumar Paluri Subject: [PATCH v2 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line Date: Mon, 2 Sep 2024 19:35:11 -0500 Message-ID: <20240903003511.1530454-3-papaluri@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240903003511.1530454-1-papaluri@amd.com> References: <20240903003511.1530454-1-papaluri@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: SJ1PEPF0000231F:EE_|DM4PR12MB6230:EE_ X-MS-Office365-Filtering-Correlation-Id: b9c1e6df-11dd-472d-a480-08dccbb06559 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|376014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?fnMSBUaZDSd2GAUwueK3pMwbJaVEVQ5OLUy9BW1GeQFFopJbptax8vLqyDHC?= =?us-ascii?Q?LadsBTZmx9wcr+UXdSLBYtXOrwiUfwjeAR/HVfwAjA/BdCn327g0SxKMar1B?= =?us-ascii?Q?BoImIroNSf0kGJMDYgnnIxHtOLhEBs7YuUDajDdY3lkDghafpPuA2c8jh4Wg?= =?us-ascii?Q?j+5/TXANAjKsVTUsphpxb10uX6yvHDodxFDgaVPNxxNdyl+kqnDLj+Jvu1Jv?= =?us-ascii?Q?XDLZH5R+ev6YRednhtsX2XNPBspeMDX7uGx0MXvf/g4rWq7Mx1NQYbBJGHEc?= =?us-ascii?Q?q8OReeG3r9Xl/4zWnOHxn+sauLXCnnKmRFcD0f/lFfbQ3KK5854LlklZzcYT?= =?us-ascii?Q?52GIJAn+j5NaTFPszLpK3NisabRWo+Ux56oiCfIEPJ36yJzYWXfjj3/Va39X?= =?us-ascii?Q?okFBMK5uuXIU6AncplFIk8Y0/i4pv0mH9sV45jMFT9yugX4rr/ffFAeGkIfH?= =?us-ascii?Q?JK6ywHZVu9WOwZp22HxtuUnsOJ+3nc6pGNeKwJ99qfyyZ0G7Nqo3D+Y1GH61?= =?us-ascii?Q?809J8QLb5pEu/733nvVq4EK9QYUENqIE+E4fQxodj3UzjN2Z9OBBdHv2Uo/Z?= =?us-ascii?Q?aXHk541azK/3Gx+OFtiHEQkA9T67/xmhZUP3Sz5z5qVGLIYZrWUk6PSAqSvK?= =?us-ascii?Q?qNqQZybsxdORlNWfYI8wU0f/4H36fVs8zmB8DRxC0u8C6DFenyX2qxqmat/T?= =?us-ascii?Q?MgVAE41ELz8Lk/TxSuGxs+fX1m8ouiKrkyKhDmbG54hJe7FuSbBC0rDHE0Xb?= =?us-ascii?Q?8AwP9H1pyEii4w5M5CVPAm8FWvGbhC/NWFd4pK2eStnk8PPbnaB1gv3a0+8k?= =?us-ascii?Q?CepXtdg8aWrQ8Edyp7iTVGts/F8c72CzsODmVQ7jRpHHM8D0mkEh/ggRrjmR?= =?us-ascii?Q?c8rrt74PFz4HukNVC0hAL8JUNscczHRhCkPFfZLaj7n7qhgpIy0OhoaBqBT/?= =?us-ascii?Q?w4EcKKNt4wFSi2kTQ0EO/oh7JB8NCX97wNSTCDel8phhvPKqsjPEzINuGh6n?= =?us-ascii?Q?a9sxtNaUpq+viBHv5c8AykqiTkE0tge6e2Zig4v7rWJTbETDaubivtB8fsoV?= =?us-ascii?Q?GeEjBkPA2yAgLfm5iugphNipbR3tf/8NrjYvDDhHcmven/lrfR4ZTrLkifLE?= =?us-ascii?Q?4k2kNqeTnGw6KhYchTVN3crgdM8k6NQ79NePaOVMTTYgCpEqdrSMpnD1fZDA?= =?us-ascii?Q?p0AzPtoKAegZtLctq9KW/46VhttaRNHLMCeEccqQIOZWc9DygpsOzlm8Y7xU?= =?us-ascii?Q?1nbCvRKwa2OC4gJLTOmRTTI14MPzzRooaLDuilMNBlV0Msw9blZFO+h/meDX?= =?us-ascii?Q?6OJiNO2YEHdXNeyImKGwSoJXn2xm3lko7CgMP0/tiBOpOxdlibh28zlMlyGI?= =?us-ascii?Q?ZCwB+NTN65OtvwEiC0R7WQE0WbnaNEh4mkLp5r1SldnnrTMLCOeavqN925WG?= =?us-ascii?Q?MMy8/sDJdUp0N1YER/1Z1+mcaiQv+20i?= 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)(36860700013)(1800799024)(376014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2024 00:36:04.8417 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b9c1e6df-11dd-472d-a480-08dccbb06559 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: SJ1PEPF0000231F.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB6230 Content-Type: text/plain; charset="utf-8" Provide a "nosnp" kernel command line option to prevent enabling of the RMP and SEV-SNP features in the host/hypervisor. Not initializing the RMP removes system overhead associated with RMP checks. Co-developed-by: Eric Van Tassell Signed-off-by: Eric Van Tassell Signed-off-by: Pavan Kumar Paluri Reviewed-by: Tom Lendacky --- Documentation/arch/x86/x86_64/boot-options.rst | 3 +++ arch/x86/virt/svm/cmdline.c | 7 +++++++ 2 files changed, 10 insertions(+) diff --git a/Documentation/arch/x86/x86_64/boot-options.rst b/Documentation= /arch/x86/x86_64/boot-options.rst index 137432d34109..3d4e9a7dccf2 100644 --- a/Documentation/arch/x86/x86_64/boot-options.rst +++ b/Documentation/arch/x86/x86_64/boot-options.rst @@ -317,3 +317,6 @@ The available options are: =20 debug Enable debug messages. + + nosnp + Do not enable SEV-SNP (applies to host/hypervisor only). diff --git a/arch/x86/virt/svm/cmdline.c b/arch/x86/virt/svm/cmdline.c index 4fe34e831d8f..43039ec67606 100644 --- a/arch/x86/virt/svm/cmdline.c +++ b/arch/x86/virt/svm/cmdline.c @@ -10,6 +10,7 @@ #include #include =20 +#include #include =20 struct sev_config sev_cfg; @@ -24,6 +25,12 @@ static int __init init_sev_config(char *str) continue; } =20 + if (!strcmp(s, "nosnp")) { + setup_clear_cpu_cap(X86_FEATURE_SEV_SNP); + cc_platform_clear(CC_ATTR_HOST_SEV_SNP); + continue; + } + pr_info("SEV command-line option '%s' was not recognized\n", s); } =20 --=20 2.34.1