[PATCH v3 26/62] KVM: x86: Move IRQ routing/delivery APIs from x86.c => irq.c

Sean Christopherson
2025-06-11T22:47:41Z

Move a bunch of IRQ routing and delivery APIs from x86.c to irq.c. x86.c
has grown quite fat, and irq.c is the perfect landing spot.

Opportunistically rewrite kvm_arch_irq_bypass_del_producer()'s comment, as
the existing comment has several typos and is rather confusing.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/irq.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 87 ---------------------------------------------
2 files changed, 88 insertions(+), 87 deletions(-)

diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index a0b1499baf6e..b9d3ec72037c 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -11,6 +11,7 @@

#include <linux/export.h>
#include <linux/kvm_host.h>
+#include <linux/kvm_irqfd.h>

#include "hyperv.h"
#include "ioapic.h"
@@ -332,6 +333,18 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
return -EWOULDBLOCK;
}

+int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
+ bool line_status)
+{
+ if (!irqchip_in_kernel(kvm))
+ return -ENXIO;
+
+ irq_event->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
+ irq_event->irq, irq_event->level,
+ line_status);
+ return 0;
+}
+
bool kvm_arch_can_set_irq_routing(struct kvm *kvm)
{
return irqchip_in_kernel(kvm);
@@ -495,6 +508,81 @@ void kvm_arch_irq_routing_update(struct kvm *kvm)
kvm_make_scan_ioapic_request(kvm);
}

+int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
+ struct irq_bypass_producer *prod)
+{
+ struct kvm_kernel_irqfd *irqfd =
+ container_of(cons, struct kvm_kernel_irqfd, consumer);
+ struct kvm *kvm = irqfd->kvm;
+ int ret = 0;
+
+ kvm_arch_start_assignment(irqfd->kvm);
+
+ spin_lock_irq(&kvm->irqfds.lock);
+ irqfd->producer = prod;
+
+ if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
+ ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
+ irqfd->gsi, &irqfd->irq_entry);
+ if (ret)
+ kvm_arch_end_assignment(irqfd->kvm);
+ }
+ spin_unlock_irq(&kvm->irqfds.lock);
+
+ return ret;
+}
+
+void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
+ struct irq_bypass_producer *prod)
+{
+ struct kvm_kernel_irqfd *irqfd =
+ container_of(cons, struct kvm_kernel_irqfd, consumer);
+ struct kvm *kvm = irqfd->kvm;
+ int ret;
+
+ WARN_ON(irqfd->producer != prod);
+
+ /*
+ * If the producer of an IRQ that is currently being posted to a vCPU
+ * is unregistered, change the associated IRTE back to remapped mode as
+ * the IRQ has been released (or repurposed) by the device driver, i.e.
+ * KVM must relinquish control of the IRTE.
+ */
+ spin_lock_irq(&kvm->irqfds.lock);
+ irqfd->producer = NULL;
+
+ if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
+ ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
+ irqfd->gsi, NULL);
+ if (ret)
+ pr_info("irq bypass consumer (token %p) unregistration fails: %d\n",
+ irqfd->consumer.token, ret);
+ }
+
+ spin_unlock_irq(&kvm->irqfds.lock);
+
+
+ kvm_arch_end_assignment(irqfd->kvm);
+}
+
+int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+ struct kvm_kernel_irq_routing_entry *old,
+ struct kvm_kernel_irq_routing_entry *new)
+{
+ return kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, irqfd->producer->irq,
+ irqfd->gsi, new);
+}
+
+bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,
+ struct kvm_kernel_irq_routing_entry *new)
+{
+ if (old->type != KVM_IRQ_ROUTING_MSI ||
+ new->type != KVM_IRQ_ROUTING_MSI)
+ return true;
+
+ return !!memcmp(&old->msi, &new->msi, sizeof(new->msi));
+}
+
#ifdef CONFIG_KVM_IOAPIC
#define IOAPIC_ROUTING_ENTRY(irq) \
{ .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f1b0dbce9a8b..5ba5e28532de 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6420,18 +6420,6 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
kvm_vcpu_kick(vcpu);
}

-int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
- bool line_status)
-{
- if (!irqchip_in_kernel(kvm))
- return -ENXIO;
-
- irq_event->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
- irq_event->irq, irq_event->level,
- line_status);
- return 0;
-}
-
int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
struct kvm_enable_cap *cap)
{
@@ -13504,81 +13492,6 @@ bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
}
EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);

-int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
- struct irq_bypass_producer *prod)
-{
- struct kvm_kernel_irqfd *irqfd =
- container_of(cons, struct kvm_kernel_irqfd, consumer);
- struct kvm *kvm = irqfd->kvm;
- int ret = 0;
-
- kvm_arch_start_assignment(irqfd->kvm);
-
- spin_lock_irq(&kvm->irqfds.lock);
- irqfd->producer = prod;
-
- if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
- ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
- irqfd->gsi, &irqfd->irq_entry);
- if (ret)
- kvm_arch_end_assignment(irqfd->kvm);
- }
- spin_unlock_irq(&kvm->irqfds.lock);
-
- return ret;
-}
-
-void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
- struct irq_bypass_producer *prod)
-{
- struct kvm_kernel_irqfd *irqfd =
- container_of(cons, struct kvm_kernel_irqfd, consumer);
- struct kvm *kvm = irqfd->kvm;
- int ret;
-
- WARN_ON(irqfd->producer != prod);
-
- /*
- * When producer of consumer is unregistered, we change back to
- * remapped mode, so we can re-use the current implementation
- * when the irq is masked/disabled or the consumer side (KVM
- * int this case doesn't want to receive the interrupts.
- */
- spin_lock_irq(&kvm->irqfds.lock);
- irqfd->producer = NULL;
-
- if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
- ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
- irqfd->gsi, NULL);
- if (ret)
- pr_info("irq bypass consumer (token %p) unregistration fails: %d\n",
- irqfd->consumer.token, ret);
- }
-
- spin_unlock_irq(&kvm->irqfds.lock);
-
-
- kvm_arch_end_assignment(irqfd->kvm);
-}
-
-int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
- struct kvm_kernel_irq_routing_entry *old,
- struct kvm_kernel_irq_routing_entry *new)
-{
- return kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, irqfd->producer->irq,
- irqfd->gsi, new);
-}
-
-bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,
- struct kvm_kernel_irq_routing_entry *new)
-{
- if (old->type != KVM_IRQ_ROUTING_MSI ||
- new->type != KVM_IRQ_ROUTING_MSI)
- return true;
-
- return !!memcmp(&old->msi, &new->msi, sizeof(new->msi));
-}
-
bool kvm_vector_hashing_enabled(void)
{
return vector_hashing;
--
2.50.0.rc1.591.g9c95f17f64-goog