KVM: x86: Move PIT ioctl helpers to i8254.c

Move the PIT ioctl helpers to i8254.c, i.e. to the file that implements
PIT emulation.  Eliminating PIT code in x86.c will allow adding a Kconfig
to control support for in-kernel I/O APIC, PIC, and PIT emulation with
minimal #ifdefs.

Opportunistically make kvm_pit_set_reinject() and kvm_pit_load_count()
local to i8254.c as they were only publicly visible to make them available
to the ioctl helpers.

No functional change intended.

Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20250611213557.294358-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/i8254.c

@@ -288,7 +288,7 @@ static inline void kvm_pit_reset_reinject(struct kvm_pit *pit)
 	atomic_set(&pit->pit_state.irq_ack, 1);
 }
 
-void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
+static void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
 {
 	struct kvm_kpit_state *ps = &pit->pit_state;
 	struct kvm *kvm = pit->kvm;
@@ -400,8 +400,8 @@ static void pit_load_count(struct kvm_pit *pit, int channel, u32 val)
 	}
 }
 
-void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
-		int hpet_legacy_start)
+static void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
+			       int hpet_legacy_start)
 {
 	u8 saved_mode;
 
@@ -649,6 +649,79 @@ static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 		kvm_pit_reset_reinject(pit);
 }
 
+int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
+{
+	struct kvm_kpit_state *kps = &kvm->arch.vpit->pit_state;
+
+	BUILD_BUG_ON(sizeof(*ps) != sizeof(kps->channels));
+
+	mutex_lock(&kps->lock);
+	memcpy(ps, &kps->channels, sizeof(*ps));
+	mutex_unlock(&kps->lock);
+	return 0;
+}
+
+int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
+{
+	int i;
+	struct kvm_pit *pit = kvm->arch.vpit;
+
+	mutex_lock(&pit->pit_state.lock);
+	memcpy(&pit->pit_state.channels, ps, sizeof(*ps));
+	for (i = 0; i < 3; i++)
+		kvm_pit_load_count(pit, i, ps->channels[i].count, 0);
+	mutex_unlock(&pit->pit_state.lock);
+	return 0;
+}
+
+int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
+{
+	mutex_lock(&kvm->arch.vpit->pit_state.lock);
+	memcpy(ps->channels, &kvm->arch.vpit->pit_state.channels,
+		sizeof(ps->channels));
+	ps->flags = kvm->arch.vpit->pit_state.flags;
+	mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+	memset(&ps->reserved, 0, sizeof(ps->reserved));
+	return 0;
+}
+
+int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
+{
+	int start = 0;
+	int i;
+	u32 prev_legacy, cur_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(&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(pit, i, pit->pit_state.channels[i].count,
+				   start && i == 0);
+	mutex_unlock(&pit->pit_state.lock);
+	return 0;
+}
+
+int kvm_vm_ioctl_reinject(struct kvm *kvm, struct kvm_reinject_control *control)
+{
+	struct kvm_pit *pit = kvm->arch.vpit;
+
+	/* pit->pit_state.lock was overloaded to prevent userspace from getting
+	 * an inconsistent state after running multiple KVM_REINJECT_CONTROL
+	 * ioctls in parallel.  Use a separate lock if that ioctl isn't rare.
+	 */
+	mutex_lock(&pit->pit_state.lock);
+	kvm_pit_set_reinject(pit, control->pit_reinject);
+	mutex_unlock(&pit->pit_state.lock);
+
+	return 0;
+}
+
 static const struct kvm_io_device_ops pit_dev_ops = {
 	.read     = pit_ioport_read,
 	.write    = pit_ioport_write,

arch/x86/kvm/i8254.h

@@ -6,6 +6,8 @@
 
 #include <kvm/iodev.h>
 
+#include <uapi/asm/kvm.h>
+
 struct kvm_kpit_channel_state {
 	u32 count; /* can be 65536 */
 	u16 latched_count;
@@ -55,11 +57,13 @@ struct kvm_pit {
 #define KVM_MAX_PIT_INTR_INTERVAL   HZ / 100
 #define KVM_PIT_CHANNEL_MASK	    0x3
 
+int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps);
+int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps);
+int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps);
+int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps);
+int kvm_vm_ioctl_reinject(struct kvm *kvm, struct kvm_reinject_control *control);
+
 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags);
 void kvm_free_pit(struct kvm *kvm);
 
-void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
-		int hpet_legacy_start);
-void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject);
-
 #endif

arch/x86/kvm/x86.c

@@ -6450,80 +6450,6 @@ static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
 	return r;
 }
 
-static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
-{
-	struct kvm_kpit_state *kps = &kvm->arch.vpit->pit_state;
-
-	BUILD_BUG_ON(sizeof(*ps) != sizeof(kps->channels));
-
-	mutex_lock(&kps->lock);
-	memcpy(ps, &kps->channels, sizeof(*ps));
-	mutex_unlock(&kps->lock);
-	return 0;
-}
-
-static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
-{
-	int i;
-	struct kvm_pit *pit = kvm->arch.vpit;
-
-	mutex_lock(&pit->pit_state.lock);
-	memcpy(&pit->pit_state.channels, ps, sizeof(*ps));
-	for (i = 0; i < 3; i++)
-		kvm_pit_load_count(pit, i, ps->channels[i].count, 0);
-	mutex_unlock(&pit->pit_state.lock);
-	return 0;
-}
-
-static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
-{
-	mutex_lock(&kvm->arch.vpit->pit_state.lock);
-	memcpy(ps->channels, &kvm->arch.vpit->pit_state.channels,
-		sizeof(ps->channels));
-	ps->flags = kvm->arch.vpit->pit_state.flags;
-	mutex_unlock(&kvm->arch.vpit->pit_state.lock);
-	memset(&ps->reserved, 0, sizeof(ps->reserved));
-	return 0;
-}
-
-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;
-	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(&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(pit, i, pit->pit_state.channels[i].count,
-				   start && i == 0);
-	mutex_unlock(&pit->pit_state.lock);
-	return 0;
-}
-
-static int kvm_vm_ioctl_reinject(struct kvm *kvm,
-				 struct kvm_reinject_control *control)
-{
-	struct kvm_pit *pit = kvm->arch.vpit;
-
-	/* pit->pit_state.lock was overloaded to prevent userspace from getting
-	 * an inconsistent state after running multiple KVM_REINJECT_CONTROL
-	 * ioctls in parallel.  Use a separate lock if that ioctl isn't rare.
-	 */
-	mutex_lock(&pit->pit_state.lock);
-	kvm_pit_set_reinject(pit, control->pit_reinject);
-	mutex_unlock(&pit->pit_state.lock);
-
-	return 0;
-}
-
 void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {