On Thu, Jul 07, 2016 at 11:42:15AM +0200, Peter Zijlstra wrote:

+static void update_steal_time_preempt(struct kvm_vcpu *vcpu)
+{
+	struct kvm_steal_time *st;
+
+	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
+		return;
+
+	if (unlikely(kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
+		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
+		return;
+
+	st = &vcpu->arch.st.steal;
+
+	st->pad[KVM_ST_PAD_PREEMPT] = 1; /* we've stopped running */

So maybe have this be:

	... = kvm_vcpu_running();

That avoids marking the vcpu preempted when we do hlt and such.

+	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
+		st, sizeof(struct kvm_steal_time));
+}