x86/apic: Remove X86_IRQ_ALLOC_CONTIGUOUS_VECTORS

Now that the PCI/MSI core code does early checking for multi-MSI support
X86_IRQ_ALLOC_CONTIGUOUS_VECTORS is not required anymore.

Remove the flag and rely on MSI_FLAG_MULTI_PCI_MSI.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20221111122015.865042356@linutronix.de

arch/x86/include/asm/irqdomain.h

@@ -7,9 +7,7 @@
 
 #ifdef CONFIG_X86_LOCAL_APIC
 enum {
-	/* Allocate contiguous CPU vectors */
-	X86_IRQ_ALLOC_CONTIGUOUS_VECTORS		= 0x1,
-	X86_IRQ_ALLOC_LEGACY				= 0x2,
+	X86_IRQ_ALLOC_LEGACY				= 0x1,
 };
 
 extern int x86_fwspec_is_ioapic(struct irq_fwspec *fwspec);

arch/x86/kernel/apic/msi.c

@@ -161,12 +161,10 @@ int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
 		    msi_alloc_info_t *arg)
 {
 	init_irq_alloc_info(arg, NULL);
-	if (to_pci_dev(dev)->msix_enabled) {
+	if (to_pci_dev(dev)->msix_enabled)
 		arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSIX;
-	} else {
+	else
 		arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSI;
-		arg->flags |= X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
-	}
 
 	return 0;
 }

arch/x86/kernel/apic/vector.c

@@ -539,10 +539,6 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq,
 	if (disable_apic)
 		return -ENXIO;
 
-	/* Currently vector allocator can't guarantee contiguous allocations */
-	if ((info->flags & X86_IRQ_ALLOC_CONTIGUOUS_VECTORS) && nr_irqs > 1)
-		return -ENOSYS;
-
 	/*
 	 * Catch any attempt to touch the cascade interrupt on a PIC
 	 * equipped system.

drivers/iommu/amd/iommu.c

@@ -3297,13 +3297,6 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
 	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
 		return -EINVAL;
 
-	/*
-	 * With IRQ remapping enabled, don't need contiguous CPU vectors
-	 * to support multiple MSI interrupts.
-	 */
-	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
-		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
-
 	sbdf = get_devid(info);
 	if (sbdf < 0)
 		return -EINVAL;

drivers/iommu/intel/irq_remapping.c

@@ -1337,13 +1337,6 @@ static int intel_irq_remapping_alloc(struct irq_domain *domain,
 	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
 		return -EINVAL;
 
-	/*
-	 * With IRQ remapping enabled, don't need contiguous CPU vectors
-	 * to support multiple MSI interrupts.
-	 */
-	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
-		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
-
 	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
 	if (ret < 0)
 		return ret;

drivers/pci/controller/pci-hyperv.c

@@ -611,20 +611,7 @@ static unsigned int hv_msi_get_int_vector(struct irq_data *data)
 	return cfg->vector;
 }
 
-static int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
-			  int nvec, msi_alloc_info_t *info)
-{
-	int ret = pci_msi_prepare(domain, dev, nvec, info);
-
-	/*
-	 * By using the interrupt remapper in the hypervisor IOMMU, contiguous
-	 * CPU vectors is not needed for multi-MSI
-	 */
-	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
-		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
-
-	return ret;
-}
+#define hv_msi_prepare		pci_msi_prepare
 
 /**
  * hv_arch_irq_unmask() - "Unmask" the IRQ by setting its current