KVM: LAPIC: Extract adaptive tune timer advancement logic

Extract adaptive tune timer advancement logic to a single function.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Rename new function. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4924f83..c12b090 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1501,11 +1501,40 @@ static inline void __wait_lapic_expire(struct kvm_vcpu *vcpu, u64 guest_cycles)
        }
 }
 
-void wait_lapic_expire(struct kvm_vcpu *vcpu)
+static inline void adjust_lapic_timer_advance(struct kvm_vcpu *vcpu,
+                                             u64 guest_tsc, u64 tsc_deadline)
 {
        struct kvm_lapic *apic = vcpu->arch.apic;
        u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns;
-       u64 guest_tsc, tsc_deadline, ns;
+       u64 ns;
+
+       /* too early */
+       if (guest_tsc < tsc_deadline) {
+               ns = (tsc_deadline - guest_tsc) * 1000000ULL;
+               do_div(ns, vcpu->arch.virtual_tsc_khz);
+               timer_advance_ns -= min((u32)ns,
+                       timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+       } else {
+       /* too late */
+               ns = (guest_tsc - tsc_deadline) * 1000000ULL;
+               do_div(ns, vcpu->arch.virtual_tsc_khz);
+               timer_advance_ns += min((u32)ns,
+                       timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+       }
+
+       if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
+               apic->lapic_timer.timer_advance_adjust_done = true;
+       if (unlikely(timer_advance_ns > 5000)) {
+               timer_advance_ns = 0;
+               apic->lapic_timer.timer_advance_adjust_done = true;
+       }
+       apic->lapic_timer.timer_advance_ns = timer_advance_ns;
+}
+
+void wait_lapic_expire(struct kvm_vcpu *vcpu)
+{
+       struct kvm_lapic *apic = vcpu->arch.apic;
+       u64 guest_tsc, tsc_deadline;
 
        if (apic->lapic_timer.expired_tscdeadline == 0)
                return;
@@ -1521,28 +1550,8 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
        if (guest_tsc < tsc_deadline)
                __wait_lapic_expire(vcpu, tsc_deadline - guest_tsc);
 
-       if (!apic->lapic_timer.timer_advance_adjust_done) {
-               /* too early */
-               if (guest_tsc < tsc_deadline) {
-                       ns = (tsc_deadline - guest_tsc) * 1000000ULL;
-                       do_div(ns, vcpu->arch.virtual_tsc_khz);
-                       timer_advance_ns -= min((u32)ns,
-                               timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
-               } else {
-               /* too late */
-                       ns = (guest_tsc - tsc_deadline) * 1000000ULL;
-                       do_div(ns, vcpu->arch.virtual_tsc_khz);
-                       timer_advance_ns += min((u32)ns,
-                               timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
-               }
-               if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
-                       apic->lapic_timer.timer_advance_adjust_done = true;
-               if (unlikely(timer_advance_ns > 5000)) {
-                       timer_advance_ns = 0;
-                       apic->lapic_timer.timer_advance_adjust_done = true;
-               }
-               apic->lapic_timer.timer_advance_ns = timer_advance_ns;
-       }
+       if (unlikely(!apic->lapic_timer.timer_advance_adjust_done))
+               adjust_lapic_timer_advance(vcpu, guest_tsc, tsc_deadline);
 }
 
 static void start_sw_tscdeadline(struct kvm_lapic *apic)