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b=U+IF2o2bnY01qFykikzV1I6i8ltUf7KghIeYSzyKUU95Ne06SyoyEQqb5EHUMoo+/IPfN2LjkmNpDqeOOLgL3a0iJlGhAe5g6HxvPd/DARu/QA++hYDZOkBju0T7XKT75VzJgc25OoNz1thOo6Ct2UKZZjJnWRsLzOYTO6+Z4Ws= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=microsoft.com; Received: from BL0PR2101MB1092.namprd21.prod.outlook.com (2603:10b6:207:30::23) by MW4PR21MB2075.namprd21.prod.outlook.com (2603:10b6:303:122::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6745.3; Sun, 20 Aug 2023 20:28:04 +0000 Received: from BL0PR2101MB1092.namprd21.prod.outlook.com ([fe80::b3df:a8e9:52dd:dfad]) by BL0PR2101MB1092.namprd21.prod.outlook.com ([fe80::b3df:a8e9:52dd:dfad%5]) with mapi id 15.20.6745.001; Sun, 20 Aug 2023 20:28:04 +0000 From: Dexuan Cui To: ak@linux.intel.com, arnd@arndb.de, bp@alien8.de, brijesh.singh@amd.com, dan.j.williams@intel.com, dave.hansen@intel.com, dave.hansen@linux.intel.com, haiyangz@microsoft.com, hpa@zytor.com, jane.chu@oracle.com, kirill.shutemov@linux.intel.com, kys@microsoft.com, linux-hyperv@vger.kernel.org, luto@kernel.org, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com, tglx@linutronix.de, tony.luck@intel.com, wei.liu@kernel.org, Jason@zx2c4.com, nik.borisov@suse.com, mikelley@microsoft.com Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Tianyu.Lan@microsoft.com, rick.p.edgecombe@intel.com, andavis@redhat.com, mheslin@redhat.com, vkuznets@redhat.com, xiaoyao.li@intel.com, Dexuan Cui Subject: [PATCH v2 5/9] Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM Date: Sun, 20 Aug 2023 13:27:11 -0700 Message-Id: <20230820202715.29006-6-decui@microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230820202715.29006-1-decui@microsoft.com> References: <20230820202715.29006-1-decui@microsoft.com> Content-Type: text/plain X-ClientProxiedBy: MW4PR03CA0005.namprd03.prod.outlook.com (2603:10b6:303:8f::10) To BL0PR2101MB1092.namprd21.prod.outlook.com (2603:10b6:207:30::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL0PR2101MB1092:EE_|MW4PR21MB2075:EE_ X-MS-Office365-Filtering-Correlation-Id: 18485514-e6e1-45ad-aa14-08dba1bbf4fa X-LD-Processed: 72f988bf-86f1-41af-91ab-2d7cd011db47,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?GQShKX3iXH4bJpPfN+Jo7HLHlrrqkvMoiIN6/Rm+iwhaef9vGZGV0n6/TKY8?= =?us-ascii?Q?bq+vCM9ZflgRLtMX/loUgR4NG0pFSsjtUgOArsR/jI+PbLiOYP+fNs/o4Xso?= =?us-ascii?Q?Bl62aVvsL7Qm7VHh6cTptA4/saculoQgLZTI1HIFeak9J+GwtCMBIGiNmtN6?= =?us-ascii?Q?M2Hp4rS5Bd5kaeVJ6h39dPpU5izcd2rflTqlhDVyenby0JZaQE/ps0PsmEEf?= =?us-ascii?Q?qvQFRfDvwHisH4WCOddwZI2OOSZwOB85ETeUhXsQ5tnVO9Os7+rzspCaKJ8M?= =?us-ascii?Q?STf0iSIG1MSgjNj8atzaZp/sRZsGgIsV2F2nLXt0Mp1yGLGO+YsycT0RTBpw?= =?us-ascii?Q?UcbhzM2dMC8uG+hVwOVB6L5v0uR9msml3wvMw7U5etv/xuwuztANHehHc6XO?= =?us-ascii?Q?a6kR21z9s6tnNqTMXuGT/0xlzNN4jYCN/RLrSi3K283wE8+zodRhIl7KMFOE?= =?us-ascii?Q?/xgTIwmXjYVHs6yMgOId6Yymmje9/VOzBj88OlC/uI5quKuj8AlZUQeCcYQP?= =?us-ascii?Q?v8lNBQ3jzLEyaQuZlBjiZeOxQtb808MlZmyPup/yLRrPnN2Ca207/ogDUkiA?= =?us-ascii?Q?1gIElPyoyfam8DQrkSfFhtExUNo5KpEEHOaHMyNmz2IDaCOWYwiHUNUE/VG0?= =?us-ascii?Q?7QDGnyHrxtNbO/jyBzSKBReXk9Ah8agd7P6hoibb756EL/0R+bidKba42/vY?= =?us-ascii?Q?NkEHE++eqesT3bjAXA67JAi0507qtU/Um3Nk+KihoetZJeZya1NlO9Sa6W+n?= =?us-ascii?Q?G4Nykz5cPx/G63jI/yrO7GjKw+s42um3VNMxdlPzea5QWC335/dEbrwNwask?= =?us-ascii?Q?rdthvbu4IzJRtGI4Gr9vn7t+Fb0+L5MQLFfy6B5ZAmpfELMivShZYNFvoxJ+?= =?us-ascii?Q?TduUQZpyZXFtRwINJuXD3NBeRmtQA8xRuquqkcLe+5QkmZRZsIp16b0Fq8NB?= =?us-ascii?Q?7hLp7QD2cN54UJFqWt1/F3q1kM17Bxc2lUukIe+hqB/UXV4Zb2KDqZuQXyN5?= =?us-ascii?Q?hoV8QlvR3suFFp18flSY5Jp/sllc2wkxL7aaQnW9c2ICOeOnggUsF2rI4tbs?= =?us-ascii?Q?6xmLmihU0Upz9QEjJ3GPFi88IX4vVkM/ZsWFQcsAXF+jgsDFbuNkkypSNpwH?= =?us-ascii?Q?MDFYWatIwCT3GZqfTCpp9RWxaKBuspjGZvLbtv5QdkLYM25st4D6jFRHrjL1?= =?us-ascii?Q?Zs+qKXJjAjdDvNGcsIGknciIdSBnq6E/ghZH6TuTLJQkNtzKWtJaM09Nze6d?= =?us-ascii?Q?Ygebwx4t3wNCAmw89uUYzZOaF4hKAS+BvIEF1rRX5lFlg31MA0tG3MqHMD+R?= =?us-ascii?Q?AF3IRdlAef8HeZZIJEu6t3DuZFZZRaLkPo/8DD4OVKEWAcAbgbetpsEI1ZTf?= =?us-ascii?Q?cLWDa9RNMiPS/X0lSCiT76/I0gqiPGKCT3HiKK3o+RsDGDSarMlHy29wdw5n?= =?us-ascii?Q?yu7KPslEUaC/SMoxa5XT2ovzjjEHNlzd1DFpf12cqfOOWtszepQ+/1VsARZa?= =?us-ascii?Q?Yxokh/rmTYPO0PIeTzb6/c7KJ82YsLX15tMHslvXwCb0U4sSx7VPidRXL1Cw?= =?us-ascii?Q?eNSFwpkfBmzWZrEd9LtgRgZaldpLanB/I2ejU+iM/uVBBAiSKSL4giR/eP/J?= =?us-ascii?Q?WQNtcqmhW6HY/l99x2m9j+NqD7Ri2QczgwxJimKn4lQG?= X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 18485514-e6e1-45ad-aa14-08dba1bbf4fa X-MS-Exchange-CrossTenant-AuthSource: BL0PR2101MB1092.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Aug 2023 20:28:04.6124 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: qCv3xJeI7b9ITgfQ00lG8jBbyE6NRoOeAJUyCeDlbL7k7j5oCZLgc1aN9YnMssLhK/HEpnb0BjMxXhLfTZ0iNQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR21MB2075 Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Don't set *this_cpu_ptr(hyperv_pcpu_input_arg) before the function set_memory_decrypted() returns, otherwise we run into this ticky issue: For a fully enlightened TDX/SNP VM, in hv_common_cpu_init(), *this_cpu_ptr(hyperv_pcpu_input_arg) is an encrypted page before the set_memory_decrypted() returns. When such a VM has more than 64 VPs, if the hyperv_pcpu_input_arg is not NULL, hv_common_cpu_init() -> set_memory_decrypted() -> ... -> cpa_flush() -> on_each_cpu() -> ... -> hv_send_ipi_mask() -> ... -> __send_ipi_mask_ex() tries to call hv_do_fast_hypercall16() with the hyperv_pcpu_input_arg as the hypercall input page, which must be a decrypted page in such a VM, but the page is still encrypted at this point, and a fatal fault is triggered. Fix the issue by setting *this_cpu_ptr(hyperv_pcpu_input_arg) after set_memory_decrypted(): if the hyperv_pcpu_input_arg is NULL, __send_ipi_mask_ex() returns HV_STATUS_INVALID_PARAMETER immediately, and hv_send_ipi_mask() falls back to orig_apic.send_IPI_mask(), which can use x2apic_send_IPI_all(), which may be slightly slower than the hypercall but still works correctly in such a VM. Signed-off-by: Dexuan Cui --- Changes in v2: None drivers/hv/hv_common.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 897bbb96f4118..4c858e1636da7 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -360,6 +360,7 @@ int hv_common_cpu_init(unsigned int cpu) u64 msr_vp_index; gfp_t flags; int pgcount = hv_root_partition ? 2 : 1; + void *mem; int ret; /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */ @@ -372,25 +373,40 @@ int hv_common_cpu_init(unsigned int cpu) * allocated if this CPU was previously online and then taken offline */ if (!*inputarg) { - *inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags); - if (!(*inputarg)) + mem = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags); + if (!mem) return -ENOMEM; if (hv_root_partition) { outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg); - *outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE; + *outputarg = (char *)mem + HV_HYP_PAGE_SIZE; } if (hv_isolation_type_en_snp() || hv_isolation_type_tdx()) { - ret = set_memory_decrypted((unsigned long)*inputarg, pgcount); + ret = set_memory_decrypted((unsigned long)mem, pgcount); if (ret) { - /* It may be unsafe to free *inputarg */ - *inputarg = NULL; + /* It may be unsafe to free 'mem' */ return ret; } - memset(*inputarg, 0x00, pgcount * PAGE_SIZE); + memset(mem, 0x00, pgcount * HV_HYP_PAGE_SIZE); } + + /* + * In a fully enlightened TDX/SNP VM with more than 64 VPs, if + * hyperv_pcpu_input_arg is not NULL, set_memory_decrypted() -> + * ... -> cpa_flush()-> ... -> __send_ipi_mask_ex() tries to + * use hyperv_pcpu_input_arg as the hypercall input page, which + * must be a decrypted page in such a VM, but the page is still + * encrypted before set_memory_decrypted() returns. Fix this by + * setting *inputarg after the above set_memory_decrypted(): if + * hyperv_pcpu_input_arg is NULL, __send_ipi_mask_ex() returns + * HV_STATUS_INVALID_PARAMETER immediately, and the function + * hv_send_ipi_mask() falls back to orig_apic.send_IPI_mask(), + * which may be slightly slower than the hypercall, but still + * works correctly in such a VM. + */ + *inputarg = mem; } msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX); -- 2.25.1