iommu/vt-d: Switch to MSI parent domains

Remove the global PCI/MSI irqdomain implementation and provide the required
MSI parent ops so the PCI/MSI code can detect the new parent and setup per
device domains.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221124232326.151226317@linutronix.de

arch/x86/kernel/apic/msi.c

@@ -217,6 +217,8 @@ static bool x86_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 		/* See msi_set_affinity() for the gory details */
 		info->flags |= MSI_FLAG_NOMASK_QUIRK;
 		break;
+	case DOMAIN_BUS_DMAR:
+		break;
 	default:
 		WARN_ON_ONCE(1);
 		return false;

drivers/iommu/intel/iommu.h

@@ -600,7 +600,6 @@ struct intel_iommu {
 #ifdef CONFIG_IRQ_REMAP
 	struct ir_table *ir_table;	/* Interrupt remapping info */
 	struct irq_domain *ir_domain;
-	struct irq_domain *ir_msi_domain;
 #endif
 	struct iommu_device iommu;  /* IOMMU core code handle */
 	int		node;

drivers/iommu/intel/irq_remapping.c

@@ -82,6 +82,7 @@ static const struct irq_domain_ops intel_ir_domain_ops;
 
 static void iommu_disable_irq_remapping(struct intel_iommu *iommu);
 static int __init parse_ioapics_under_ir(void);
+static const struct msi_parent_ops dmar_msi_parent_ops;
 
 static bool ir_pre_enabled(struct intel_iommu *iommu)
 {
@@ -230,7 +231,7 @@ static struct irq_domain *map_dev_to_ir(struct pci_dev *dev)
 {
 	struct dmar_drhd_unit *drhd = dmar_find_matched_drhd_unit(dev);
 
-	return drhd ? drhd->iommu->ir_msi_domain : NULL;
+	return drhd ? drhd->iommu->ir_domain : NULL;
 }
 
 static int clear_entries(struct irq_2_iommu *irq_iommu)
@@ -573,10 +574,10 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
 		pr_err("IR%d: failed to allocate irqdomain\n", iommu->seq_id);
 		goto out_free_fwnode;
 	}
-	iommu->ir_msi_domain =
-		arch_create_remap_msi_irq_domain(iommu->ir_domain,
-						 "INTEL-IR-MSI",
-						 iommu->seq_id);
+
+	irq_domain_update_bus_token(iommu->ir_domain,  DOMAIN_BUS_DMAR);
+	iommu->ir_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
+	iommu->ir_domain->msi_parent_ops = &dmar_msi_parent_ops;
 
 	ir_table->base = page_address(pages);
 	ir_table->bitmap = bitmap;
@@ -620,9 +621,6 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
 	return 0;
 
 out_free_ir_domain:
-	if (iommu->ir_msi_domain)
-		irq_domain_remove(iommu->ir_msi_domain);
-	iommu->ir_msi_domain = NULL;
 	irq_domain_remove(iommu->ir_domain);
 	iommu->ir_domain = NULL;
 out_free_fwnode:
@@ -644,13 +642,6 @@ static void intel_teardown_irq_remapping(struct intel_iommu *iommu)
 	struct fwnode_handle *fn;
 
 	if (iommu && iommu->ir_table) {
-		if (iommu->ir_msi_domain) {
-			fn = iommu->ir_msi_domain->fwnode;
-
-			irq_domain_remove(iommu->ir_msi_domain);
-			irq_domain_free_fwnode(fn);
-			iommu->ir_msi_domain = NULL;
-		}
 		if (iommu->ir_domain) {
 			fn = iommu->ir_domain->fwnode;
 
@@ -1437,6 +1428,12 @@ static const struct irq_domain_ops intel_ir_domain_ops = {
 	.deactivate = intel_irq_remapping_deactivate,
 };
 
+static const struct msi_parent_ops dmar_msi_parent_ops = {
+	.supported_flags	= X86_VECTOR_MSI_FLAGS_SUPPORTED | MSI_FLAG_MULTI_PCI_MSI,
+	.prefix			= "IR-",
+	.init_dev_msi_info	= msi_parent_init_dev_msi_info,
+};
+
 /*
  * Support of Interrupt Remapping Unit Hotplug
  */

include/linux/irqdomain_defs.h

@@ -23,6 +23,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_VMD_MSI,
 	DOMAIN_BUS_PCI_DEVICE_MSI,
 	DOMAIN_BUS_PCI_DEVICE_MSIX,
+	DOMAIN_BUS_DMAR,
 };
 
 #endif /* _LINUX_IRQDOMAIN_DEFS_H */