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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 , Dov Murik , Tobin Feldman-Fitzthum , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH Part1 v5 34/38] x86/sev: Add snp_msg_seqno() helper To: Borislav Petkov References: <20210820151933.22401-1-brijesh.singh@amd.com> <20210820151933.22401-35-brijesh.singh@amd.com> <9e0e734d-7d2f-4703-b9ce-8362f0c740f4@amd.com> From: Brijesh Singh Message-ID: <01b9c0e8-a808-83a7-214f-ea62136ffa0b@amd.com> Date: Thu, 2 Sep 2021 10:27:38 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SA0PR11CA0059.namprd11.prod.outlook.com (2603:10b6:806:d0::34) To SN6PR12MB2718.namprd12.prod.outlook.com (2603:10b6:805:6f::22) MIME-Version: 1.0 Received: from [10.236.31.95] (165.204.77.1) by SA0PR11CA0059.namprd11.prod.outlook.com (2603:10b6:806:d0::34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4478.19 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?TEZENEdnTkNvaGR2LzlDSTI4dEhuWkRVSmx5bHg1WjZ3N1NyYzlUc3RYcDI4?= =?utf-8?B?MkJEMjJnSHc0QmcyUEhsdzY5WVplVkxmMnJ4TzNzVjFCUGM0NE1pd2Nrb0o3?= =?utf-8?B?cldkV0dOSklreS8vZjI2dXNIeHlISS9KbFgzOUhqVzB2bVh2QUdNTE9yeGZq?= =?utf-8?B?WnZZbUZtUFN0QzRHVGhRS3R1dUpEVmJ2cTQrY1pZdVgrQU5BZjIrYk53UGpJ?= =?utf-8?B?QTBKY2dSQjFPL2RmR3VoYmRORWlQa294dkdKbktlV1ZRK3FOZ1BSNzBOWE50?= =?utf-8?B?cUV5S05CNDhvQ1VidE9RT3lXbTgzVDZWeU1GVkdDektON3VQMXZHTXNUY3ls?= =?utf-8?B?eXd2Z1pSeGdFWHkzeDh0Wi9VZWh2QWdwZm41NTJlTzZxeHRUdjc3SWduaVlJ?= =?utf-8?B?YzQvVFVzY1RFVEttZXlqRmtNUWxVVXRnV3JJV2R3R2xNbW1jc1lIR01rcjhl?= =?utf-8?B?clE5MXo4VEcrcXFTM21GVkx1ZVNsdEIvaC9mT2ZJZlpneDByNWJXS3hLUjJR?= =?utf-8?B?R2xJYmpZa2lBRjJucnd3ckV4Vll4K2hGdXJJZ3dMNEZMMjIrdzcydEtqNzEy?= =?utf-8?B?M3p4ampNM1RjUzI1Wk9FcTViaEZLQlorWWFHZTl3dDVEVGFjYjhMMEpqVzRi?= =?utf-8?B?Q2pJdDRzRk02bzQvK01IcnhlZU5WbEhqUmtOWU5KeUNhU2VSMVo0V0FaczJl?= =?utf-8?B?ekhUM0VyUi9zTzJ6VnZYc05IQks0Y1Blam1aU2RVZVZZcVp5MXhPUS82TFRU?= =?utf-8?B?ZzdpREhVT0JFRS91WjB5S09ORmt1RGZyWnJaOThad3JjSHlZb2x5b092MHlI?= =?utf-8?B?SjEyTWJleGxzYWFQSUljc0kvNWNGQ2U4TzZhcWdIbHpPcDhZWlVZZmttY1VE?= =?utf-8?B?Q3Z6VnRoT2dOZ3hkbkhvWXcrbWhRL290Ym44VkE0ZklQcEh2aUVTcXJrbU00?= =?utf-8?B?NU5iZU9QNUk5NE9TQ0ZoaEZJRnRjeHNUeHM4YTVwNlpGZ1NRUE40QjVqMk1P?= =?utf-8?B?UjZLMXZXWnNLL1luRWRUdTRtakpibGhMWlp4bnZpSDI0Q05DY28zMWh2MndY?= =?utf-8?B?S2xQTVA3OU5SNDFxbkdyZjE0ZHo1UC8wWXhlNEJsWkpieXhEemFScEpOYnZw?= =?utf-8?B?WHhlaGMrY2RjUllrMkUreUdhZjI0TUU2NFBQcHVtVDlqOTc0M3NHZXdYTGpi?= =?utf-8?B?U0g1YjJwaVBmelRrWWNaWWFsb0hqdndoZWNmSUJpdW5NaklqWVZPbmJ1TGdp?= =?utf-8?B?VzREVVRiL1hQZWRwQW85RkI2Y29jYU5FUmQvaVBvZFdOdkJRZHV3V3VpZmtN?= =?utf-8?B?TjFRUTgrSCtvZWdyNnRUSjVRcnREdGlsbGVTaVhkK25RbVM5UzlheHI2c1JJ?= =?utf-8?B?K0pOcUJLZTVFUklwcU9lcnFHcW01emFva2tKMFJOK1Y5aklDUzBlWGNBRGR6?= =?utf-8?B?azNwNWY4LzAyblZhQlRBUjc5NmR0WGF2TE1wQk0zc0dkQ3l3Z3Q3WlJBcExZ?= =?utf-8?B?U004QVhSdGNlUld0Q2VadzhPYXQ1YnE1TndEeWpsWnhhOEo0TkxQY01FQjBN?= =?utf-8?B?RnRpYXV3U2Y5bUVtL1BEcU44aVZQV1lDczBDcTNNRkRkTFZjZU5uQ0VhdSto?= =?utf-8?B?VkNEWlMraW1mQzR0UHlHR09QeSs3ckVOTVRCeWNKSlQ1a1o4R3JDaitCOVhH?= =?utf-8?B?ei8rMEthSGJpT2xIcGE0UTJabWNyU3QzZEgrbkZ3U0Y1WkVJM2pWTE9uSXQy?= =?utf-8?Q?D1VQ9EVfPkOLAWVpfspmjffr2hHJTFGkiOLh2q1?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 77610795-2842-4a2f-43aa-08d96e2633f7 X-MS-Exchange-CrossTenant-AuthSource: SN6PR12MB2718.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2021 15:27:41.2799 (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: i8teaP8OhzOVNdwJ7t3vExFGBwR377BIgzo122K/oL2vyCEfr9S6aHpuEcF4O0jYcQ6E6o0tqhXwGEu7d8/waQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4525 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On 9/2/21 6:26 AM, Borislav Petkov wrote: > On Mon, Aug 30, 2021 at 10:07:39AM -0500, Brijesh Singh wrote: >> The SNP firmware spec says that counter must begin with the 1. > > So put that in the comment and explain what 0 is: magic or invalid or > whatnot and why is that so and that it is spec-ed this way, etc. > > Just having it there without a reasoning makes one wonder whether that's > some arbitrary limitation or so. Agreed, I will add a comment explaining it. > >> During the GHCB writing the seqno use to be 32-bit value and hence the GHCB >> spec choose the 32-bit value but recently the SNP firmware changed it from >> the 32 to 64. So, now we are left with the option of limiting the sequence >> number to 32-bit. If we go beyond 32-bit then all we can do is fail the >> call. If we pass the value of zero then FW will fail the call. > > That sounds weird again. So make it 64-bit like the FW and fix the spec. > >> I just choose the smaller name but I have no issues matching with the spec. >> Also those keys does not have anything to do with the VMPL level. The >> secrets page provides 4 different keys and they are referred as vmpck0..3 >> and each of them have a sequence numbers associated with it. >> >> In GHCB v3 we probably need to rework the structure name. > > You can point to the spec section so that readers can find the struct > layout there. > I will add comment that this for spec 0.9+. thanks