KVM: i8254: pass struct kvm_pit instead of kvm in PIT

This patch passes struct kvm_pit into internal PIT functions.
Those functions used to get PIT through kvm->arch.vpit, even though most
of them never used *kvm for other purposes.  Another benefit is that we
don't need to set kvm->arch.vpit during initialization.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/i8254.h

@@ -56,9 +56,11 @@ struct kvm_pit {
 #define KVM_MAX_PIT_INTR_INTERVAL   HZ / 100
 #define KVM_PIT_CHANNEL_MASK	    0x3
 
-void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start);
 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags);
 void kvm_free_pit(struct kvm *kvm);
+
 void kvm_pit_reset(struct kvm_pit *pit);
+void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
+		int hpet_legacy_start);
 
 #endif

arch/x86/kvm/x86.c

@@ -3613,11 +3613,13 @@ static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 {
 	int i;
-	mutex_lock(&kvm->arch.vpit->pit_state.lock);
-	memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state));
+	struct kvm_pit *pit = kvm->arch.vpit;
+
+	mutex_lock(&pit->pit_state.lock);
+	memcpy(&pit->pit_state, ps, sizeof(struct kvm_pit_state));
 	for (i = 0; i < 3; i++)
-		kvm_pit_load_count(kvm, i, ps->channels[i].count, 0);
-	mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+		kvm_pit_load_count(pit, i, ps->channels[i].count, 0);
+	mutex_unlock(&pit->pit_state.lock);
 	return 0;
 }
 
@@ -3637,18 +3639,20 @@ static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
 	int start = 0;
 	int i;
 	u32 prev_legacy, cur_legacy;
-	mutex_lock(&kvm->arch.vpit->pit_state.lock);
-	prev_legacy = kvm->arch.vpit->pit_state.flags & KVM_PIT_FLAGS_HPET_LEGACY;
+	struct kvm_pit *pit = kvm->arch.vpit;
+
+	mutex_lock(&pit->pit_state.lock);
+	prev_legacy = pit->pit_state.flags & KVM_PIT_FLAGS_HPET_LEGACY;
 	cur_legacy = ps->flags & KVM_PIT_FLAGS_HPET_LEGACY;
 	if (!prev_legacy && cur_legacy)
 		start = 1;
-	memcpy(&kvm->arch.vpit->pit_state.channels, &ps->channels,
-	       sizeof(kvm->arch.vpit->pit_state.channels));
-	kvm->arch.vpit->pit_state.flags = ps->flags;
+	memcpy(&pit->pit_state.channels, &ps->channels,
+	       sizeof(pit->pit_state.channels));
+	pit->pit_state.flags = ps->flags;
 	for (i = 0; i < 3; i++)
-		kvm_pit_load_count(kvm, i, kvm->arch.vpit->pit_state.channels[i].count,
+		kvm_pit_load_count(pit, i, pit->pit_state.channels[i].count,
 				   start && i == 0);
-	mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+	mutex_unlock(&pit->pit_state.lock);
 	return 0;
 }