KVM: LAPIC: extract start_sw_period() to handle periodic/oneshot mode

Extract start_sw_period() to handle periodic/oneshot mode, it will be
used by later patch.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

1 files changed, 47 insertions, 42 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 23b99f305382..dad743e3c1f5 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1347,6 +1347,50 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic)
         local_irq_restore(flags);
 }
 
+static void start_sw_period(struct kvm_lapic *apic)
+{
+        ktime_t now;
+
+        /* lapic timer in oneshot or periodic mode */
+        now = apic->lapic_timer.timer.base->get_time();
+        apic->lapic_timer.period = (u64)kvm_lapic_get_reg(apic, APIC_TMICT)
+                    * APIC_BUS_CYCLE_NS * apic->divide_count;
+
+        if (!apic->lapic_timer.period)
+                return;
+        /*
+         * Do not allow the guest to program periodic timers with small
+         * interval, since the hrtimers are not throttled by the host
+         * scheduler.
+         */
+        if (apic_lvtt_period(apic)) {
+                s64 min_period = min_timer_period_us * 1000LL;
+
+                if (apic->lapic_timer.period < min_period) {
+                        pr_info_ratelimited(
+                            "kvm: vcpu %i: requested %lld ns "
+                            "lapic timer period limited to %lld ns\n",
+                            apic->vcpu->vcpu_id,
+                            apic->lapic_timer.period, min_period);
+                        apic->lapic_timer.period = min_period;
+                }
+        }
+
+        hrtimer_start(&apic->lapic_timer.timer,
+                      ktime_add_ns(now, apic->lapic_timer.period),
+                      HRTIMER_MODE_ABS_PINNED);
+
+        apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
+                   PRIx64 ", "
+                   "timer initial count 0x%x, period %lldns, "
+                   "expire @ 0x%016" PRIx64 ".\n", __func__,
+                   APIC_BUS_CYCLE_NS, ktime_to_ns(now),
+                   kvm_lapic_get_reg(apic, APIC_TMICT),
+                   apic->lapic_timer.period,
+                   ktime_to_ns(ktime_add_ns(now,
+                                apic->lapic_timer.period)));
+}
+
 bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
 {
         if (!lapic_in_kernel(vcpu))
@@ -1424,50 +1468,11 @@ EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
 
 static void start_apic_timer(struct kvm_lapic *apic)
 {
-        ktime_t now;
-
         atomic_set(&apic->lapic_timer.pending, 0);
 
-        if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
-                /* lapic timer in oneshot or periodic mode */
-                now = apic->lapic_timer.timer.base->get_time();
-                apic->lapic_timer.period = (u64)kvm_lapic_get_reg(apic, APIC_TMICT)
-                            * APIC_BUS_CYCLE_NS * apic->divide_count;
-
-                if (!apic->lapic_timer.period)
-                        return;
-                /*
-                 * Do not allow the guest to program periodic timers with small
-                 * interval, since the hrtimers are not throttled by the host
-                 * scheduler.
-                 */
-                if (apic_lvtt_period(apic)) {
-                        s64 min_period = min_timer_period_us * 1000LL;
-
-                        if (apic->lapic_timer.period < min_period) {
-                                pr_info_ratelimited(
-                                    "kvm: vcpu %i: requested %lld ns "
-                                    "lapic timer period limited to %lld ns\n",
-                                    apic->vcpu->vcpu_id,
-                                    apic->lapic_timer.period, min_period);
-                                apic->lapic_timer.period = min_period;
-                        }
-                }
-
-                hrtimer_start(&apic->lapic_timer.timer,
-                              ktime_add_ns(now, apic->lapic_timer.period),
-                              HRTIMER_MODE_ABS_PINNED);
-
-                apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
-                           PRIx64 ", "
-                           "timer initial count 0x%x, period %lldns, "
-                           "expire @ 0x%016" PRIx64 ".\n", __func__,
-                           APIC_BUS_CYCLE_NS, ktime_to_ns(now),
-                           kvm_lapic_get_reg(apic, APIC_TMICT),
-                           apic->lapic_timer.period,
-                           ktime_to_ns(ktime_add_ns(now,
-                                        apic->lapic_timer.period)));
-        } else if (apic_lvtt_tscdeadline(apic)) {
+        if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
+                start_sw_period(apic);
+        else if (apic_lvtt_tscdeadline(apic)) {
                 if (!(kvm_x86_ops->set_hv_timer && start_hv_tscdeadline(apic)))
                         start_sw_tscdeadline(apic);
         }