diff --git a/xen/arch/ppc/include/asm/irq.h b/xen/arch/ppc/include/asm/irq.h
index 5c37d0cf25..fa70fd7d46 100644
--- a/xen/arch/ppc/include/asm/irq.h
+++ b/xen/arch/ppc/include/asm/irq.h
@@ -30,4 +30,10 @@ static inline int platform_get_irq(const struct dt_device_node *device, int inde
     BUG_ON("unimplemented");
 }
 
+static inline void *irq_to_desc(unsigned int irq)
+{
+    BUG_ON("unimplemented");
+}
+#define irq_to_desc irq_to_desc
+
 #endif /* __ASM_PPC_IRQ_H__ */
diff --git a/xen/arch/riscv/include/asm/irq.h b/xen/arch/riscv/include/asm/irq.h
index 2a48da2651..8fe87b19e9 100644
--- a/xen/arch/riscv/include/asm/irq.h
+++ b/xen/arch/riscv/include/asm/irq.h
@@ -25,6 +25,12 @@ static inline void arch_move_irqs(struct vcpu *v)
     BUG_ON("unimplemented");
 }
 
+static inline void *irq_to_desc(unsigned int irq)
+{
+    BUG_ON("unimplemented");
+}
+#define irq_to_desc irq_to_desc
+
 #endif /* ASM__RISCV__IRQ_H */
 
 /*