x86/irq: Add allocation type for parent domain retrieval

irq_remapping_ir_irq_domain() is used to retrieve the remapping parent
domain for an allocation type. irq_remapping_irq_domain() is for retrieving
the actual device domain for allocating interrupts for a device.

The two functions are similar and can be unified by using explicit modes
for parent irq domain retrieval.

Add X86_IRQ_ALLOC_TYPE_IOAPIC/HPET_GET_PARENT and use it in the iommu
implementations. Drop the parent domain retrieval for PCI_MSI/X as that is
unused.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20200826112331.436350257@linutronix.de

arch/x86/include/asm/hw_irq.h

@@ -40,6 +40,8 @@ enum irq_alloc_type {
 	X86_IRQ_ALLOC_TYPE_PCI_MSIX,
 	X86_IRQ_ALLOC_TYPE_DMAR,
 	X86_IRQ_ALLOC_TYPE_UV,
+	X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT,
+	X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT,
 };
 
 struct irq_alloc_info {

arch/x86/kernel/apic/io_apic.c

@@ -2296,7 +2296,7 @@ static int mp_irqdomain_create(int ioapic)
 		return 0;
 
 	init_irq_alloc_info(&info, NULL);
-	info.type = X86_IRQ_ALLOC_TYPE_IOAPIC;
+	info.type = X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT;
 	info.ioapic_id = mpc_ioapic_id(ioapic);
 	parent = irq_remapping_get_ir_irq_domain(&info);
 	if (!parent)

arch/x86/kernel/apic/msi.c

@@ -472,7 +472,7 @@ struct irq_domain *hpet_create_irq_domain(int hpet_id)
 	domain_info->data = (void *)(long)hpet_id;
 
 	init_irq_alloc_info(&info, NULL);
-	info.type = X86_IRQ_ALLOC_TYPE_HPET;
+	info.type = X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT;
 	info.hpet_id = hpet_id;
 	parent = irq_remapping_get_ir_irq_domain(&info);
 	if (parent == NULL)

drivers/iommu/amd/iommu.c

@@ -3548,6 +3548,14 @@ static struct irq_domain *get_ir_irq_domain(struct irq_alloc_info *info)
 	if (!info)
 		return NULL;
 
+	switch (info->type) {
+	case X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT:
+	case X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT:
+		break;
+	default:
+		return NULL;
+	}
+
 	devid = get_devid(info);
 	if (devid >= 0) {
 		iommu = amd_iommu_rlookup_table[devid];

drivers/iommu/hyperv-iommu.c

@@ -184,7 +184,7 @@ static int __init hyperv_enable_irq_remapping(void)
 
 static struct irq_domain *hyperv_get_ir_irq_domain(struct irq_alloc_info *info)
 {
-	if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC)
+	if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT)
 		return ioapic_ir_domain;
 	else
 		return NULL;

drivers/iommu/intel/irq_remapping.c

@@ -1115,16 +1115,12 @@ static struct irq_domain *intel_get_ir_irq_domain(struct irq_alloc_info *info)
 		return NULL;
 
 	switch (info->type) {
-	case X86_IRQ_ALLOC_TYPE_IOAPIC:
+	case X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT:
 		iommu = map_ioapic_to_ir(info->ioapic_id);
 		break;
-	case X86_IRQ_ALLOC_TYPE_HPET:
+	case X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT:
 		iommu = map_hpet_to_ir(info->hpet_id);
 		break;
-	case X86_IRQ_ALLOC_TYPE_PCI_MSI:
-	case X86_IRQ_ALLOC_TYPE_PCI_MSIX:
-		iommu = map_dev_to_ir(info->msi_dev);
-		break;
 	default:
 		BUG_ON(1);
 		break;