From: Ketan Chaturvedi <Ketan.Chaturvedi@xxxxxxx>
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.
As the frequency needs to be set in the SNP_LAUNCH_START command, userspace
should set the frequency using the KVM_CAP_SET_TSC_KHZ VM ioctl instead of
the VCPU ioctl. The desired_tsc_khz defaults to kvm->arch.default_tsc_khz.
Signed-off-by: Ketan Chaturvedi <Ketan.Chaturvedi@xxxxxxx>
Co-developed-by: Nikunj A Dadhania <nikunj@xxxxxxx>
Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
arch/x86/include/uapi/asm/kvm.h | 3 ++-
arch/x86/kvm/svm/sev.c | 15 ++++++++++++++-
2 files changed, 16 insertions(+), 2 deletions(-)
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 80a80929e6a3..c33b3bc598a7 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2226,6 +2226,14 @@ 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)) {
+ if (!kvm->arch.default_tsc_khz)
+ return -EINVAL;
+
+ start.desired_tsc_khz = kvm->arch.default_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) {
@@ -2466,7 +2474,9 @@ static int snp_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}
- svm->vcpu.arch.guest_state_protected = true;
+ vcpu->arch.guest_state_protected = true;
+ vcpu->arch.guest_tsc_protected = snp_secure_tsc_enabled(kvm);
+
/*
* SEV-ES (and thus SNP) guest mandates LBR Virtualization to
* be _always_ ON. Enable it only after setting
@@ -3079,6 +3089,9 @@ 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)
--
2.43.0
