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Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , tony.luck@intel.com, npmccallum@redhat.com Subject: Re: [PATCH Part1 RFC v3 11/22] x86/sev: Add helper for validating pages in early enc attribute changes To: Borislav Petkov References: <20210602140416.23573-1-brijesh.singh@amd.com> <20210602140416.23573-12-brijesh.singh@amd.com> <70db789d-b1aa-c355-2d16-51ace4666b3f@amd.com> <9f012bcb-4756-600d-6fe8-b1db9b972f17@amd.com> <91db9dfc-068a-3709-925b-9e249fbe8f6f@amd.com> From: Brijesh Singh Message-ID: <06ffeaae-259c-67ea-617c-f1d8c1e1c015@amd.com> Date: Wed, 16 Jun 2021 09:37:34 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [165.204.77.11] X-ClientProxiedBy: SA9PR13CA0120.namprd13.prod.outlook.com (2603:10b6:806:24::35) To DM6PR12MB2714.namprd12.prod.outlook.com (2603:10b6:5:42::18) X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [172.31.11.236] (165.204.77.11) by SA9PR13CA0120.namprd13.prod.outlook.com (2603:10b6:806:24::35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4242.9 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?U1NTSE1XYVFKYks4Y0ZNelJzL1J4Y3grMzlUa1NTZENoemE0bDg2RUFzL0ZS?= =?utf-8?B?cGFVYUxQZzlLWm5zSEJXbnc1Q2pSYWxXdEZxZ3UvOFlKUE9mNElMK2lzRWNB?= =?utf-8?B?ZEdXUDBBL2YxNk8wdEo4UnRRQ3lCRlp0WExtcnNnMGRSL0EycVFMcTVxVDc2?= =?utf-8?B?YW1sa0F5dDYyYWU5Ujd3cGR1VG9KVWFyYWx1ZVV5YWF1S1FIbitQMWhoU2Ur?= =?utf-8?B?dGlGYUlWNzJZTnF5eFFoMnkwQjNoNnRLZ2FQUjNOR0w2ZVRFQXVzLzgxNmMw?= =?utf-8?B?Yk5uek5iZHhRaXZlSmwwMzc3UTdsOTFTZC9FSUtVcGVXalV1eUdyQktRMXMx?= =?utf-8?B?OE1MbmFOb3hBeXFJSkhFak1oOUpCeGJ6QWVUZk1EY3VON3RwWUlqczFzN3VW?= =?utf-8?B?blVIazJySEo5VWJSWWlaSXkrSGl3bEdnOEdsN2NiT2hkZHpDVmM3aWkrNldX?= =?utf-8?B?QjFxaWM1TFJnYWVqdVBBSkI1OGJGTkphcEhyYzR2ZG83NE0yQ0liTkFNV2hs?= =?utf-8?B?UXFZOXpRSWRnMXRFamtiK1lTNmVrL1orL1lIOGFvbmd3ajduRTJMVHo4L3dL?= =?utf-8?B?amxXSlM4Mmh3aDNlMDZhZmVVVzY4SHJFc084U3dGTCt3dmZqT1dXdC9CRFZD?= =?utf-8?B?MURodnIrSHVXTC9oUjdwOUYxbWpnNldVcW5ZSHZ6alN1dEVxZEVIRkI5Wnlo?= =?utf-8?B?SWJ3bTBxaXQ5NEhDaW9sSzVMSlVNNGxvemYxa01MMTl5ZTNFcjVuZ1FQVStI?= =?utf-8?B?T0FDNGIwZjRXUFpSNkwzcGRoSFF5eUxXQi8yRk9QRHMwNmlLZFM2Y1RGOVBB?= =?utf-8?B?NGlkTHRSSzZGcC9oaGF4bjdMUGgvNG1Zc2FHam9wbWxseCsyNEtyTERuaGFP?= =?utf-8?B?UEpqYStiMmZ6cE9qd1hEVHNlYWZDbncza0NieCtGb25FWnd4blFYRUJmbmt0?= =?utf-8?B?cEF3R01wVytYeklQTERtZEF5UlgzeVFDN05xZjVEc3lxdXRXU0FSU0VKdUIr?= =?utf-8?B?QmF6WHZGUEgxNzRFVTdMeWxYUFRKYllvVXd4ZElPQyszNEx6TUYvWDZoV3BT?= =?utf-8?B?S2dUOEpmRzZpOHQzVEVlZmFsQWpKa2lxdXk3K0gzNTNBQVF2cmdmWHBuQW1P?= =?utf-8?B?MHBhUGRsWUtpUnA4SGtjejVxRDEyU24vdXAwOFdYUWtMUlFRbytNcFZJQ1ZQ?= =?utf-8?B?bEJvaEhNK1I4M1V1Sm44ZjVLaWZwc2V6YjFZZzNQbCt4dlhFelhHSmtzTFlC?= =?utf-8?B?ZUxaQ0ROMmlOUGhkMG9JZ2NSU1FuQmlRSkxGR2NzcmxaTGhZYkhyZ0hiUjZT?= =?utf-8?B?YU9HNzExT3p2YVFTV3g1dWcvYmVEWmltQkQ4SEFvdy9jaDNQc2oxVnVUcW1J?= =?utf-8?B?M1FjZHA3VFNzazhkZXBva2tFVldITmVFa3E2dytIUmI4UHVOS2QrMmpnbjVM?= =?utf-8?B?VU55ZU00eEdlUm12b1JEL2grcURnUXJJWC8wMVB5VTcxR3hGa2EvbHV6ZC9F?= =?utf-8?B?MFpwbm5JM0tDOXh3cEJueGhXaExHV1FSUDl1ckt4aDBNSW9RVnNKU3k0YmVy?= =?utf-8?B?aXB0Nm5nTXJ6UDdmSmwxYjQ0NXNUZWRNREhxb0RUMHcxb2xxMFN4VzZhdzd5?= =?utf-8?B?emJQSFNlYUNQcE1iRFczQ1Jpam1sM1B2RjFub1NzRW1yVk1iSERON1IyODZm?= =?utf-8?B?T3I1UmhTZGR4TDZ0UjVFVUw4NmhzZ2RXaE84QkdxVEpLNHRWOWc1bzVPV1RH?= =?utf-8?Q?AVFN3BFeKScwnLH+LKbstdI9cN40iSLTBbpDqoQ?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: cadbac02-1a42-451b-6bc6-08d930d44a7d X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB2714.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Jun 2021 14:37:39.8594 (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: kIi0xuc/tBk3a2naSd9od9rOiymn/2OP38OTeO7WYDAYcKW/VO3MATzK0U9Ly6nvRWdlsqxg+lntpD3PoA7eWA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR1201MB0268 On 6/16/2021 9:36 AM, Brijesh Singh wrote: > > > On 6/16/2021 8:10 AM, Brijesh Singh wrote: >> >> On 6/16/21 8:02 AM, Borislav Petkov wrote: >>> On Wed, Jun 16, 2021 at 07:49:25AM -0500, Brijesh Singh wrote: >>>> If you still think ... >>> I think you should answer my question first: >>> >>>> Imagine you're a guest owner and you haven't written the SNP code and >>>> you don't know how it works. >>>> >>>> You start a guest in the public cloud and it fails because the >>>> hypervisor violates the GHCB protocol and all that guest prints before >>>> it dies is >>>> >>>> "general request termination" >>>> >>>> How are you - the guest owner - going to find out what exactly happened? >>>> >>>> Call support? >>> And let me paraphrase it again: if the error condition with which the >>> guest terminates is not uniquely identifiable but simply a "general >>> request", how are such conditions going to be debugged? >>> I thought I said it somewhere in our previous conversation, I would look >> at the KVM trace log, each vmgexit entry and exit are logged. The log >> contains full GHCB MSR value, and in it you can see both the request and >> response code and decode the failure reason. >> > > I now realized that in this case we may not have the trace's. It's > a production environment and my development machine :(. I am mean to say *not* my development machine