linux-kernel - [PATCH v2 09/18] KVM: x86: Move kvm_{request,free}_irq_source

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Message-ID: <20250611213557.294358-10-seanjc@google.com>
Date: Wed, 11 Jun 2025 14:35:48 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Kai Huang <kai.huang@...el.com>
Subject: [PATCH v2 09/18] KVM: x86: Move kvm_{request,free}_irq_source_id() to
 i8254.c (PIT)

Move kvm_{request,free}_irq_source_id() to i8254.c, i.e. the dedicated PIT
emulation file, in anticipation of removing them entirely in favor of
hardcoding the PIT's "requested" source ID (the source ID can only ever be
'2', and the request can never fail).

No functional change intended.

Acked-by: Kai Huang <kai.huang@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/i8254.c     | 44 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/irq_comm.c  | 44 ----------------------------------------
 include/linux/kvm_host.h |  2 --
 3 files changed, 44 insertions(+), 46 deletions(-)

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 59f956f35f4c..2bb223bf0dac 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -641,6 +641,50 @@ static void kvm_pit_reset(struct kvm_pit *pit)
 	kvm_pit_reset_reinject(pit);
 }
 
+static int kvm_request_irq_source_id(struct kvm *kvm)
+{
+	unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
+	int irq_source_id;
+
+	mutex_lock(&kvm->irq_lock);
+	irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
+
+	if (irq_source_id >= BITS_PER_LONG) {
+		pr_warn("exhausted allocatable IRQ sources!\n");
+		irq_source_id = -EFAULT;
+		goto unlock;
+	}
+
+	ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
+	ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
+	set_bit(irq_source_id, bitmap);
+unlock:
+	mutex_unlock(&kvm->irq_lock);
+
+	return irq_source_id;
+}
+
+static void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
+{
+	ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
+	ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
+
+	mutex_lock(&kvm->irq_lock);
+	if (irq_source_id < 0 ||
+	    irq_source_id >= BITS_PER_LONG) {
+		pr_err("IRQ source ID out of range!\n");
+		goto unlock;
+	}
+	clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
+	if (!irqchip_full(kvm))
+		goto unlock;
+
+	kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
+	kvm_pic_clear_all(kvm->arch.vpic, irq_source_id);
+unlock:
+	mutex_unlock(&kvm->irq_lock);
+}
+
 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 {
 	struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 99c521bd9db5..138c675dc24b 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -165,50 +165,6 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
 	return -EWOULDBLOCK;
 }
 
-int kvm_request_irq_source_id(struct kvm *kvm)
-{
-	unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
-	int irq_source_id;
-
-	mutex_lock(&kvm->irq_lock);
-	irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
-
-	if (irq_source_id >= BITS_PER_LONG) {
-		pr_warn("exhausted allocatable IRQ sources!\n");
-		irq_source_id = -EFAULT;
-		goto unlock;
-	}
-
-	ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
-	ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
-	set_bit(irq_source_id, bitmap);
-unlock:
-	mutex_unlock(&kvm->irq_lock);
-
-	return irq_source_id;
-}
-
-void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
-{
-	ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
-	ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
-
-	mutex_lock(&kvm->irq_lock);
-	if (irq_source_id < 0 ||
-	    irq_source_id >= BITS_PER_LONG) {
-		pr_err("IRQ source ID out of range!\n");
-		goto unlock;
-	}
-	clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
-	if (!irqchip_full(kvm))
-		goto unlock;
-
-	kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
-	kvm_pic_clear_all(kvm->arch.vpic, irq_source_id);
-unlock:
-	mutex_unlock(&kvm->irq_lock);
-}
-
 void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
 				    struct kvm_irq_mask_notifier *kimn)
 {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9461517b4e62..cba8fc4529e8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1784,8 +1784,6 @@ void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
-int kvm_request_irq_source_id(struct kvm *kvm);
-void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
 
 /*
-- 
2.50.0.rc1.591.g9c95f17f64-goog