[PATCH v8 04/17] KVM: x86: Activate master clock immediately on vCPU creation
Sean Christopherson <[email protected]>
| Newsgroups | org.kernel.vger.linux-kernel,org.kernel.vger.kvm |
|---|---|
| Message-ID | <[email protected]> |
From: David Woodhouse <[email protected]> Previously, the master clock was only activated when the first vCPU processed KVM_REQ_MASTERCLOCK_UPDATE during KVM_RUN. This meant that KVM_GET_CLOCK could not return the host_tsc field until after the first KVM_RUN, making it impossible for userspace to follow the documented TSC migration procedure without a dummy vCPU run. Fix this by calling kvm_update_masterclock() directly from kvm_arch_vcpu_postcreate(), after kvm_synchronize_tsc() has already set all_vcpus_matched_freq. This ensures the master clock is active immediately, and KVM_GET_CLOCK returns a valid {host_tsc, realtime} pair as soon as a vCPU exists. Signed-off-by: David Woodhouse <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- arch/x86/kvm/x86.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ce6d155b2ee6..3ebcf2f27f7d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9447,6 +9447,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) return; vcpu_load(vcpu); kvm_synchronize_tsc(vcpu, NULL); + if (!vcpu->kvm->arch.use_master_clock) + kvm_update_masterclock(vcpu->kvm); vcpu_put(vcpu); /* poll control enabled by default */ -- 2.55.0.571.g244d577d93-goog