diff options
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
2 files changed, 7 insertions, 4 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 6be1ddedec49..dcddef1dd47b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -2006,7 +2006,7 @@ frequency is KHz. 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. +created vCPUs. Note, the vm ioctl is only allowed prior to creating vCPUs. 4.56 KVM_GET_TSC_KHZ -------------------- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 912260e3725d..a247f67954ea 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7326,9 +7326,12 @@ set_pit2_out: if (user_tsc_khz == 0) user_tsc_khz = tsc_khz; - WRITE_ONCE(kvm->arch.default_tsc_khz, user_tsc_khz); - r = 0; - + mutex_lock(&kvm->lock); + if (!kvm->created_vcpus) { + WRITE_ONCE(kvm->arch.default_tsc_khz, user_tsc_khz); + r = 0; + } + mutex_unlock(&kvm->lock); goto out; } case KVM_GET_TSC_KHZ: { |