KVM: PPC: Book3S HV: XIVE: Fix mapping of passthrough interrupts

PCI MSI interrupt numbers are now mapped in a PCI-MSI domain but the
underlying calls handling the passthrough of the interrupt in the
guest need a number in the XIVE IRQ domain.

Use the IRQ data mapped in the XIVE IRQ domain and not the one in the
PCI-MSI domain.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-16-clg@kaod.org

arch/powerpc/kvm/book3s_xive.c

@@ -927,7 +927,8 @@ int kvmppc_xive_set_mapped(struct kvm *kvm, unsigned long guest_irq,
 	struct kvmppc_xive *xive = kvm->arch.xive;
 	struct kvmppc_xive_src_block *sb;
 	struct kvmppc_xive_irq_state *state;
-	struct irq_data *host_data = irq_get_irq_data(host_irq);
+	struct irq_data *host_data =
+		irq_domain_get_irq_data(irq_get_default_host(), host_irq);
 	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(host_data);
 	u16 idx;
 	u8 prio;

kernel/irq/irqdomain.c

@@ -491,6 +491,7 @@ struct irq_domain *irq_get_default_host(void)
 {
 	return irq_default_domain;
 }
+EXPORT_SYMBOL_GPL(irq_get_default_host);
 
 static bool irq_domain_is_nomap(struct irq_domain *domain)
 {