Re: [PATCH v2 03/17] KVM: VMX: Move posted interrupt delivery code to common header

[Chao Gao]

>+/*
>+ * Send interrupt to vcpu via posted interrupt way.
>+ * 1. If target vcpu is running(non-root mode), send posted interrupt
>+ * notification to vcpu and hardware will sync PIR to vIRR atomically.

This comment primarily describes what kvm_vcpu_trigger_posted_interrupt() does.
And, it is not entirely accurate, as it is not necessarily the "hardware" that
syncs PIR to vIRR (see case 2 & 3 in the comment in
kvm_vcpu_trigger_posted_interrupt()).

How about:

/*
 * Post an interrupt to a vCPU's PIR and trigger the vCPU to process the
 * interrupt if necessary.
 */


Other than that, the patch looks good to me

Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx>

>+ * 2. If target vcpu isn't running(root mode), kick it to pick up the
>+ * interrupt from PIR in next vmentry.
>+ */
>+static inline void __vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu,
>+						  struct pi_desc *pi_desc, int vector)
>+{
>+	if (pi_test_and_set_pir(vector, pi_desc))
>+		return;
>+
>+	/* If a previous notification has sent the IPI, nothing to do.  */
>+	if (pi_test_and_set_on(pi_desc))
>+		return;
>+
>+	/*
>+	 * The implied barrier in pi_test_and_set_on() pairs with the smp_mb_*()
>+	 * after setting vcpu->mode in vcpu_enter_guest(), thus the vCPU is
>+	 * guaranteed to see PID.ON=1 and sync the PIR to IRR if triggering a
>+	 * posted interrupt "fails" because vcpu->mode != IN_GUEST_MODE.
>+	 */
>+	kvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);
>+}
>+