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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?YktHRFp1dVBxOFd1K3NxR1orQ3lIRlBkS1ZZdCtQOGMxVnhQWEZiWk5sY1Vi?= =?utf-8?B?U0JaU01zUTJJRXpsRHFLWnAweHY2QStKSmhqQW91bkpyVHZMblEvY0krNHY0?= =?utf-8?B?TkNzTEx0K1hZazFIUC8vaGlkTXZVZ0p5VXhqa1hnems3Z0VoZjJkK0JqZG1l?= =?utf-8?B?aVJ3eFkyeld6Q0pFZUdjYmNWeVl3ZExTN2czd2k3anowR3ppak9GVnFNR1pG?= =?utf-8?B?VURlNm1VY3diRzBpMjlNZGtnMEo2cUFXK3ZpZ1pONVpxWmsvbFVpODZMdUZH?= =?utf-8?B?SHJPcVFod3dLZDFqblhMTlBPcWJsdndsUXVvcG42YTl1Sm0vT2p0b3F5ZW4w?= =?utf-8?B?azNXdC85d21DN04xamtyVTlGWWFEMzJCY0hOVlQ4S1Z4Nnk1WU04YnJadkox?= =?utf-8?B?L1VwN3dyRWZOTU1ZelVEQjUxUTlXZi9rMnU1WFBlL3NYeE13cUV4YTdSMXNJ?= =?utf-8?B?ZU5uQmlrRjF1RXQ4UGpNbzFHSkZDRW9CMGZzanNZQ252YVY0MVJLMnc2VXpV?= =?utf-8?B?MU14OGNoMWJCTVZ3VlNqQndEKzg4T3NiNXJLOFFYRndGMUgvQjZwVWJKWFRt?= =?utf-8?B?b3ljdTdScmlRb3g0N2ZwNHpXRCtjYXBVSUppNXVYYVN5V0dGdk45NUxYSjZ2?= =?utf-8?B?TFJVeFBNTm9IN2VBRFpETHNFaEsyUW1qQTVDdkpJWE03Z2FnQm14bnNRQmdh?= =?utf-8?B?YUJvenlwSHc1STBCT3o4bTB1UXNMRzhGLzQvdEpyNW0wYU9jdkxmWFN2WXZQ?= =?utf-8?B?Q2F6WElQSWl4UGJYMWhKbythTFpLWWsrWng0Q0tONURrdkhMdENVZVFFQU15?= =?utf-8?B?YWF6aWFzVHdPbHVDMExuSDRwSkpwUktiSTNjWjVRRGNNTVVxWUYxV0t2elpU?= =?utf-8?B?TnRmbWJGcFpSZ2RuN3FaUFNmbmkyQkcybFozOXBDMEV4NTVyRFBxR3h5N3hF?= =?utf-8?B?ZTdyeGhBTFZYTXJ0S1ZNRkphQkRTR0pyakdMUmpPTENnOFk4L29RekwwWXdL?= =?utf-8?B?K2FNVE5keDNzTmp4SUE4MWh3YUw0QmtWTGR1enFVTWN3N0ZheEtSQW93UzZ4?= =?utf-8?B?bkUvNEFrZVZNQlZNMkkrTWRMQWI4dkRIK1NEb0srYlFPaURad2NlVWRsU1NP?= =?utf-8?B?bEFSSmNINUpIU2xpNERZS3FBSVdwNEVmT1g1UnZMdmJ4YkhaUjQzVVQ5M25H?= =?utf-8?B?bmwvZG5JZlY3K1Q1cGlYSEhsS3dhYmFPTzVnSWdRWlp3ZWxkaXpESmhQeGJH?= =?utf-8?B?bUFuYXoyaGhLUWlRTUlTV25LeitsL2pWVVBpaXptL0xWMFRKSDBSaXpWdk5M?= =?utf-8?B?QVZSMnZwdjFyVTVmcmh6eHdXSGUyYkZBa3JSS0hpc2doSmhKTS92ZlJ1MVdu?= =?utf-8?B?eDFhZUxhN1hKeWNnUjNaUUVWTjFkelZ2Q01UR3ozaGRuOENPeHVCcHViL2xn?= =?utf-8?B?MEprMFJYcjBQZ0xKbVRMUWVmSUZFc0Q0Rk1UVXpYTFlhcUdlNnR4VFFvam1p?= =?utf-8?B?NUtqQXhENnRXelFaWDdhZFZhRXlwS1FhSXplckpOQ1BxR3VMWTNpWFU1emM4?= =?utf-8?B?TDhkbDUrT3dBNDNUUTRybXZOUW9VQWFzVmhNZ2JOQTJBRklaSWxzeWxITGpl?= =?utf-8?B?anFHRWVTK2RuYmR1eWwzM1J4Q0tXYnVFUC91WEtqVDQwZ2Q4Q1ZQOTJjOUZT?= =?utf-8?B?OUJ1UmdrMmorUFRnRDhqNEFFYUhUZm1FOUdtMUVxdnU3MVduWGV4YjVta0pZ?= =?utf-8?Q?Pb4zX3/7wB3SIoIuinY04hjkCTD4+mA4seucxJy?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 9a1765a2-4975-4785-3186-08d993d16951 X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB5229.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Oct 2021 13:56:27.8174 (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: +509fiCbU/q/PYIB7+CnvMOkdTWuZXUlKqJRKaANoXQht8bm49bdr7xMcZg6ILgZlyy6GphjAz+/DDnYdZF5tw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB5536 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/20/21 8:39 AM, Borislav Petkov wrote: > On Wed, Oct 20, 2021 at 08:39:59PM +0800, Tianyu Lan wrote: >> Hyper-V runs paravisor in guest VMPL0 which emulates some functions >> (e.g, timer, tsc, serial console and so on) via handling VC exception. >> GHCB pages are allocated and set up by the paravisor and report to Linux >> guest via MSR register.Hyper-V SEV implementation is unenlightened guest >> case which doesn't Linux doesn't handle VC and paravisor in the VMPL0 >> handle it. > > Aha, unenlightened. > > So why don't you export the original function by doing this (only > partial diff to show intent only): > > --- > diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c > index f1d513897baf..bfe82f58508f 100644 > --- a/arch/x86/kernel/sev-shared.c > +++ b/arch/x86/kernel/sev-shared.c > @@ -125,7 +125,7 @@ static enum es_result verify_exception_info(struct ghcb *ghcb, struct es_em_ctxt > return ES_VMM_ERROR; > } > > -static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, > +static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr, > struct es_em_ctxt *ctxt, > u64 exit_code, u64 exit_info_1, > u64 exit_info_2) > @@ -138,7 +138,14 @@ static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, > ghcb_set_sw_exit_info_1(ghcb, exit_info_1); > ghcb_set_sw_exit_info_2(ghcb, exit_info_2); > > - sev_es_wr_ghcb_msr(__pa(ghcb)); > + /* > + * Hyper-V unenlightened guests use a paravisor for communicating and > + * GHCB pages are being allocated by that paravisor which uses a > + * different MSR and protocol. Just to clarify the comment, the paravisor uses the same GHCB MSR and GHCB protocol, it just can't use __pa() to get the address of the GHCB. So I expect that the Hyper-V support sets the address properly before calling this function. Thanks, Tom > + */ > + if (set_ghcb_msr) > + sev_es_wr_ghcb_msr(__pa(ghcb)); > + > VMGEXIT(); > > return verify_exception_info(ghcb, ctxt); > >