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Bae" , Thomas Gleixner , Sasha Levin , Borislav Petkov , Peter Zijlstra , Ingo Molnar References: <39d57e4d-5db4-f536-6f5e-6b0414c0dccc@amd.com> <7dedb0ab-56a6-5d96-577b-21ab1ecdad24@amd.com> <20200820151049.GA26595@sjchrist-ice> <362f5a45-b808-25ad-b99b-449e05717c4a@amd.com> <45e16c5c-ce99-33da-99c8-ea52ef0945db@amd.com> <68478297-ff21-fa38-a37b-2e1e515fdc5e@amd.com> <50e7c7f6-d212-4e90-09b7-2c568087084e@amd.com> From: Tom Lendacky Message-ID: Date: Thu, 20 Aug 2020 15:15:45 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SN2PR01CA0025.prod.exchangelabs.com (2603:10b6:804:2::35) To DM5PR12MB1355.namprd12.prod.outlook.com (2603:10b6:3:6e::7) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from 255.255.255.255 (255.255.255.255) by SN2PR01CA0025.prod.exchangelabs.com (2603:10b6:804:2::35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3305.25 via Frontend Transport; Thu, 20 Aug 2020 20:15:46 +0000 X-Originating-IP: [67.79.209.213] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: f984a151-0898-40e8-ee6f-08d84545d37f X-MS-TrafficTypeDiagnostic: DM6PR12MB3082: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: uNE7iYCMCuqjN8xiF/JpkztTH9UErm83pkr970qbRBgjITNRry3KbY6VIqFs6DvCqbNjEJYeC776b4E0pdB/Xnu6EMmFPMsATpuHvKVHpyc/xjg0R8w/zuhVooDklQMwZhy59wCPatcZlN0lyohmMYHPtfY2O90t0/08hJWor2vtbnnuULP4NXp6s7OAEYh08fyeoprv+0N0L9GAIp/h8l6t+PInezikxVo4vH85FBJe1eWpkp2YB5h8sWBf8Dg2qTo7hEmtDjgKPpyTzDNXIzpHcbbx8ZvhxOEb4f10kzJUfmJlJ1un1/AmDwu7ij85nRHymqEioKNtvGcwD8WhiAbNkItseQUBzF9yg/7TwSBdwYoMGSDXSy9hIhA1TTgXlNoHdmpSavmQTpXmr6xR9JtKzBOR4a7kW7DnwrXYAug= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM5PR12MB1355.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(136003)(366004)(396003)(39860400002)(376002)(346002)(54906003)(110136005)(6486002)(86362001)(16576012)(53546011)(110011004)(7416002)(8936002)(4744005)(4326008)(66946007)(31696002)(2906002)(31686004)(316002)(83380400001)(66556008)(478600001)(52116002)(26005)(36756003)(956004)(8676002)(186003)(5660300002)(2616005)(66476007)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: f984a151-0898-40e8-ee6f-08d84545d37f X-MS-Exchange-CrossTenant-AuthSource: DM5PR12MB1355.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Aug 2020 20:15:47.8271 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SWwHlw+d1FqbVj8B6tEQI3vqbKlObW3gqop9XMLH/qLiXVRwWCl90I4YB+oOGncouiEqkvrQoCNy0mdUND/Xpg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB3082 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/20/20 3:07 PM, Dave Hansen wrote: > On 8/20/20 12:05 PM, Tom Lendacky wrote: >>> I added a quick hack to save TSC_AUX to a new variable in the SVM >>> struct and then restore it right after VMEXIT (just after where GS is >>> restored in svm_vcpu_enter_exit()) and my guest is no longer crashing. >> >> Sorry, I mean my host is no longer crashing. > > Just to make sure I've got this: > 1. Older CPUs didn't have X86_FEATURE_RDPID > 2. FSGSBASE patches started using RDPID in the NMI entry path when > supported *AND* FSGSBASE was enabled > 3. There was a latent SVM bug which did not restore the RDPID data > before NMIs were reenabled after VMEXIT > 4. If an NMI comes in the window between VMEXIT and the > wrmsr(TSC_AUX)... boom Right, which means that the setting of TSC_AUX to the guest value needs to be moved, too. Thanks, Tom > > If FSGSBASE reverted is disabled (as Tom did on the command-line), then > the RDPID path isn't hit. > > Fun. >