KVM: LAPIC: Introduce limit_periodic_timer_frequency

Extract the logic of limit lapic periodic timer frequency to a new function,
this function will be used by later patches.

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

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 6723e2ca3d9d26e6170f89d75e084d9248030ab1..8841bb539c90b80d59bd0b1df506f9284fb7bd50 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1301,6 +1301,27 @@ static void update_divide_count(struct kvm_lapic *apic)
                                   apic->divide_count);
 }
 
+static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
+{
+       /*
+        * 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;
+               }
+       }
+}
+
 static void apic_update_lvtt(struct kvm_lapic *apic)
 {
        u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@@ -1445,23 +1466,7 @@ static bool set_target_expiration(struct kvm_lapic *apic)
        if (!apic->lapic_timer.period)
                return false;
 
-       /*
-        * 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;
-               }
-       }
+       limit_periodic_timer_frequency(apic);
 
        apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
                   PRIx64 ", "