[PATCH 6/7] KVM: lapic: Clean up the code for handling of a pre-expired hv_timer

[Sean Christopherson <sean.j.christopherson@intel.com>]

Calling apic_timer_expired() is a nop when a timer interrupt is already
pending, i.e. there's no need to call apic_timer_expired() when there's
a pending interrupt and the hv_timer wants to pend its own interrupt.
Separate the two flows to make the code more readable and to avoid an
unnecessary function call and read to ktimer->pending.

Cc: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/lapic.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 1d649a2af04c..f0be6f148a47 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1703,9 +1703,12 @@ static bool start_hv_timer(struct kvm_lapic *apic)
 	 * the window.  For periodic timer, leave the hv timer running for
 	 * simplicity, and the deadline will be recomputed on the next vmexit.
 	 */
-	if (!apic_lvtt_period(apic) && (r || atomic_read(&ktimer->pending))) {
-		if (r)
-			apic_timer_expired(apic);
+	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
+		return false;
+
+	/* set_hv_timer() returns '1' when the timer has already expired. */
+	if (r) {
+		apic_timer_expired(apic);
 		return false;
 	}
 
-- 
2.21.0