| Message ID | 20250217102237.16434-6-nikunj@amd.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Enable Secure TSC for SEV-SNP | expand |
On 2/17/25 04:22, Nikunj A Dadhania wrote: > From: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com> > > Add support for Secure TSC, allowing userspace to configure the Secure TSC > feature for SNP guests. Use the SNP specification's desired TSC frequency > parameter during the SNP_LAUNCH_START command to set the mean TSC > frequency in KHz for Secure TSC enabled guests. If the frequency is not > specified by the VMM, default to tsc_khz. > > Signed-off-by: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com> > Co-developed-by: Nikunj A Dadhania <nikunj@amd.com> > Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> > --- > arch/x86/include/uapi/asm/kvm.h | 3 ++- > arch/x86/kvm/svm/sev.c | 20 ++++++++++++++++++++ > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h > index 9e75da97bce0..87ed9f77314d 100644 > --- a/arch/x86/include/uapi/asm/kvm.h > +++ b/arch/x86/include/uapi/asm/kvm.h > @@ -836,7 +836,8 @@ struct kvm_sev_snp_launch_start { > __u64 policy; > __u8 gosvw[16]; > __u16 flags; > - __u8 pad0[6]; > + __u8 pad0[2]; > + __u32 desired_tsc_khz; > __u64 pad1[4]; > }; > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 7875bb14a2b1..0b2112360844 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -2207,6 +2207,20 @@ static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) > > start.gctx_paddr = __psp_pa(sev->snp_context); > start.policy = params.policy; > + > + if (snp_secure_tsc_enabled(kvm)) { > + u32 user_tsc_khz = params.desired_tsc_khz; > + > + /* Use tsc_khz if the VMM has not provided the TSC frequency */ > + if (!user_tsc_khz) > + user_tsc_khz = tsc_khz; > + > + start.desired_tsc_khz = user_tsc_khz; > + > + /* Set the arch default TSC for the VM*/ > + kvm->arch.default_tsc_khz = user_tsc_khz; > + } > + > memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw)); > rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error); > if (rc) { > @@ -2929,6 +2943,9 @@ void __init sev_set_cpu_caps(void) > if (sev_snp_enabled) { > kvm_cpu_cap_set(X86_FEATURE_SEV_SNP); > kvm_caps.supported_vm_types |= BIT(KVM_X86_SNP_VM); > + > + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) > + kvm_cpu_cap_set(X86_FEATURE_SNP_SECURE_TSC); kvm_cpu_cap_check_and_set() Thanks, Tom > } > } > > @@ -3061,6 +3078,9 @@ void __init sev_hardware_setup(void) > sev_supported_vmsa_features = 0; > if (sev_es_debug_swap_enabled) > sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP; > + > + if (sev_snp_enabled && cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) > + sev_supported_vmsa_features |= SVM_SEV_FEAT_SECURE_TSC; > } > > void sev_hardware_unsetup(void)
Tom Lendacky <thomas.lendacky@amd.com> writes: > On 2/17/25 04:22, Nikunj A Dadhania wrote: >> From: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com> >> if (rc) { >> @@ -2929,6 +2943,9 @@ void __init sev_set_cpu_caps(void) >> if (sev_snp_enabled) { >> kvm_cpu_cap_set(X86_FEATURE_SEV_SNP); >> kvm_caps.supported_vm_types |= BIT(KVM_X86_SNP_VM); >> + >> + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) >> + kvm_cpu_cap_set(X86_FEATURE_SNP_SECURE_TSC); > > kvm_cpu_cap_check_and_set() Sure, I have updated the patch. Regards Nikunj
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 9e75da97bce0..87ed9f77314d 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -836,7 +836,8 @@ struct kvm_sev_snp_launch_start { __u64 policy; __u8 gosvw[16]; __u16 flags; - __u8 pad0[6]; + __u8 pad0[2]; + __u32 desired_tsc_khz; __u64 pad1[4]; }; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 7875bb14a2b1..0b2112360844 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2207,6 +2207,20 @@ static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) start.gctx_paddr = __psp_pa(sev->snp_context); start.policy = params.policy; + + if (snp_secure_tsc_enabled(kvm)) { + u32 user_tsc_khz = params.desired_tsc_khz; + + /* Use tsc_khz if the VMM has not provided the TSC frequency */ + if (!user_tsc_khz) + user_tsc_khz = tsc_khz; + + start.desired_tsc_khz = user_tsc_khz; + + /* Set the arch default TSC for the VM*/ + kvm->arch.default_tsc_khz = user_tsc_khz; + } + memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw)); rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error); if (rc) { @@ -2929,6 +2943,9 @@ void __init sev_set_cpu_caps(void) if (sev_snp_enabled) { kvm_cpu_cap_set(X86_FEATURE_SEV_SNP); kvm_caps.supported_vm_types |= BIT(KVM_X86_SNP_VM); + + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) + kvm_cpu_cap_set(X86_FEATURE_SNP_SECURE_TSC); } } @@ -3061,6 +3078,9 @@ void __init sev_hardware_setup(void) sev_supported_vmsa_features = 0; if (sev_es_debug_swap_enabled) sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP; + + if (sev_snp_enabled && cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) + sev_supported_vmsa_features |= SVM_SEV_FEAT_SECURE_TSC; } void sev_hardware_unsetup(void)