KVM: PPC: Book3S HV: Use the new IRQ chip to detect passthrough interrupts

Passthrough PCI MSI interrupts are detected in KVM with a check on a
specific EOI handler (P8) or on XIVE (P9). We can now check the
PCI-MSI IRQ chip which is cleaner.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-14-clg@kaod.org

arch/powerpc/kvm/book3s_hv.c

@@ -5355,7 +5355,7 @@ static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 	 * what our real-mode EOI code does, or a XIVE interrupt
 	 */
 	chip = irq_data_get_irq_chip(&desc->irq_data);
-	if (!chip || !(is_pnv_opal_msi(chip) || is_xive_irq(chip))) {
+	if (!chip || !is_pnv_opal_msi(chip)) {
 		pr_warn("kvmppc_set_passthru_irq_hv: Could not assign IRQ map for (%d,%d)\n",
 			host_irq, guest_gsi);
 		mutex_unlock(&kvm->lock);

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -2007,13 +2007,15 @@ void pnv_set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq)
 	irq_set_chip(virq, &phb->ioda.irq_chip);
 }
 
+static struct irq_chip pnv_pci_msi_irq_chip;
+
 /*
  * Returns true iff chip is something that we could call
  * pnv_opal_pci_msi_eoi for.
  */
 bool is_pnv_opal_msi(struct irq_chip *chip)
 {
-	return chip->irq_eoi == pnv_ioda2_msi_eoi;
+	return chip->irq_eoi == pnv_ioda2_msi_eoi || chip == &pnv_pci_msi_irq_chip;
 }
 EXPORT_SYMBOL_GPL(is_pnv_opal_msi);