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-rw-r--r--Documentation/virt/kvm/api.rst7
-rw-r--r--arch/x86/kvm/x86.c4
2 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 6ab242418c92..544fb11351d9 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -2008,6 +2008,13 @@ If the KVM_CAP_VM_TSC_CONTROL capability is advertised, this can also
be used as a vm ioctl to set the initial tsc frequency of subsequently
created vCPUs.
+For TSC protected Confidential Computing (CoCo) VMs where TSC frequency
+is configured once at VM scope and remains unchanged during VM's
+lifetime, the vm ioctl should be used to configure the TSC frequency
+and the vcpu ioctl is not supported.
+
+Example of such CoCo VMs: TDX guests.
+
4.56 KVM_GET_TSC_KHZ
--------------------
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index de51dbd85a58..f133c031d737 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6188,6 +6188,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
u32 user_tsc_khz;
r = -EINVAL;
+
+ if (vcpu->arch.guest_tsc_protected)
+ goto out;
+
user_tsc_khz = (u32)arg;
if (kvm_caps.has_tsc_control &&