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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Feb 2025 09:20:18.2138 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 4c6b70f3-0568-4f03-cea4-08dd4ffd7623 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CY4PEPF0000EDD5.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5940 Tom Lendacky writes: > On 2/17/25 04:22, Nikunj A Dadhania wrote: >> @@ -3161,6 +3161,20 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) >> >> svm->tsc_aux = data; >> break; >> + case MSR_IA32_TSC: >> + /* >> + * If Secure TSC is enabled, do not emulate TSC write as TSC calculation >> + * ignores the TSC_OFFSET and TSC_SCALE control fields, record the error >> + * and return a #GP. Allow the TSC to be initialized until the guest state >> + * is protected to prevent unexpected VMM errors. >> + */ >> + if (vcpu->arch.guest_state_protected && snp_secure_tsc_enabled(vcpu->kvm)) { > > I'm not sure if it matters, but do we need to differentiate between > guest and host write in this situation at all in regards to the message > or return code? > Yes, I think we can have something like the below: + case MSR_IA32_TSC: + /* + * For Secure TSC enabled VM, do not emulate TSC write as the + * TSC calculation ignores the TSC_OFFSET and TSC_SCALE control + * fields. + * + * Guest writes: Record the error and return a #GP. + * Host writes are ignored. + */ + if (snp_secure_tsc_enabled(vcpu->kvm)) { + if (!msr->host_initiated) { + vcpu_unimpl(vcpu, "unimplemented IA32_TSC for Secure TSC\n"); + return 1; + } else + return 0; + } + + ret = kvm_set_msr_common(vcpu, msr); + break; >> + vcpu_unimpl(vcpu, "unimplemented IA32_TSC for secure tsc\n"); > > s/secure tsc/Secure TSC/ ? > Ack, Thanks Nikunj