[RFC PATCH 04/34] KVM: Add weak stubs for irqchip-related functions for Gunyah builds

[Karim Manaouil]

The generic KVM core code (e.g., kvm_main.c and eventfd.c) calls into
irqchip-specific helpers such as kvm_set_irq(), kvm_irq_map_gsi(), and
kvm_irq_map_chip_pin(). These functions are defined in kvm_irqchip.c,
which is not required or compiled when porting KVM to run on top of the
Gunyah hypervisor.

To allow building the KVM core code without linking errors in such
configurations, provide weak stub implementations of these functions
in eventfd.c. These stubs return appropriate default values (e.g., -ENXIO
or -1) to indicate that the functionality is not available.

This allows the KVM core to build successfully for platforms that do
not use the in-kernel irqchip support, such as Gunyah.

Signed-off-by: Karim Manaouil <karim.manaouil at linaro.org>
---
 virt/kvm/eventfd.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index d6702225e7f2..2a658d8277ed 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -56,6 +56,26 @@ kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 	return true;
 }
 
+int __attribute__((weak))
+kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
+		bool line_status)
+{
+	return -ENXIO;
+}
+
+int __attribute__((weak))
+kvm_irq_map_gsi(struct kvm *kvm,
+		struct kvm_kernel_irq_routing_entry *entries, int gsi)
+{
+	return 0;
+}
+
+int __attribute__((weak))
+kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+	return -1;
+}
+
 static void
 irqfd_inject(struct work_struct *work)
 {
-- 
2.39.5