Revert "iommu/vt-d: Enable PCI/IMS"

This reverts commit 810531a.

IMS (Interrupt Message Store) support appeared in v6.2, but there are no
users yet.

Remove it for now.  We can add it back when a user comes along.

Link: https://lore.kernel.org/r/20240410221307.2162676-6-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Author: bjorn-helgaas

drivers/iommu/intel/irq_remapping.c

@@ -82,7 +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, virt_dmar_msi_parent_ops;
+static const struct msi_parent_ops dmar_msi_parent_ops;
 
 static bool ir_pre_enabled(struct intel_iommu *iommu)
 {
@@ -567,11 +567,7 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
 	irq_domain_update_bus_token(iommu->ir_domain,  DOMAIN_BUS_DMAR);
 	iommu->ir_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT |
 				   IRQ_DOMAIN_FLAG_ISOLATED_MSI;
-
-	if (cap_caching_mode(iommu->cap))
-		iommu->ir_domain->msi_parent_ops = &virt_dmar_msi_parent_ops;
-	else
-		iommu->ir_domain->msi_parent_ops = &dmar_msi_parent_ops;
+	iommu->ir_domain->msi_parent_ops = &dmar_msi_parent_ops;
 
 	ir_table->base = page_address(pages);
 	ir_table->bitmap = bitmap;
@@ -1421,20 +1417,11 @@ static const struct irq_domain_ops intel_ir_domain_ops = {
 };
 
 static const struct msi_parent_ops dmar_msi_parent_ops = {
-	.supported_flags	= X86_VECTOR_MSI_FLAGS_SUPPORTED |
-				  MSI_FLAG_MULTI_PCI_MSI |
-				  MSI_FLAG_PCI_IMS,
+	.supported_flags	= X86_VECTOR_MSI_FLAGS_SUPPORTED | MSI_FLAG_MULTI_PCI_MSI,
 	.prefix			= "IR-",
 	.init_dev_msi_info	= msi_parent_init_dev_msi_info,
 };
 
-static const struct msi_parent_ops virt_dmar_msi_parent_ops = {
-	.supported_flags	= X86_VECTOR_MSI_FLAGS_SUPPORTED |
-				  MSI_FLAG_MULTI_PCI_MSI,
-	.prefix			= "vIR-",
-	.init_dev_msi_info	= msi_parent_init_dev_msi_info,
-};
-
 /*
  * Support of Interrupt Remapping Unit Hotplug
  */