arch/x86/kernel/apic/msi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Support of MSI, HPET and DMAR interrupts.
  *
  * Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
  *	Moved from arch/x86/kernel/apic/io_apic.c.
  * Jiang Liu <jiang.liu@linux.intel.com>
  *	Convert to hierarchical irqdomain
  */
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/pci.h>
 #include <linux/dmar.h>
 #include <linux/hpet.h>
 #include <linux/msi.h>
 #include <asm/irqdomain.h>
 #include <asm/hpet.h>
 #include <asm/hw_irq.h>
 #include <asm/apic.h>
 #include <asm/irq_remapping.h>

 struct irq_domain *x86_pci_msi_default_domain __ro_after_init;

 static void irq_msi_update_msg(struct irq_data *irqd, struct irq_cfg *cfg)
 {
 	struct msi_msg msg[2] = { [1] = { }, };

 	__irq_msi_compose_msg(cfg, msg, false);
 	irq_data_get_irq_chip(irqd)->irq_write_msi_msg(irqd, msg);
 }

 static int
 msi_set_affinity(struct irq_data *irqd, const struct cpumask *mask, bool force)
 {
 	struct irq_cfg old_cfg, *cfg = irqd_cfg(irqd);
 	struct irq_data *parent = irqd->parent_data;
 	unsigned int cpu;
 	int ret;

 	/* Save the current configuration */
 	cpu = cpumask_first(irq_data_get_effective_affinity_mask(irqd));
 	old_cfg = *cfg;

 	/* Allocate a new target vector */
 	ret = parent->chip->irq_set_affinity(parent, mask, force);
 	if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
 		return ret;

 	/*
 	 * For non-maskable and non-remapped MSI interrupts the migration
 	 * to a different destination CPU and a different vector has to be
 	 * done careful to handle the possible stray interrupt which can be
 	 * caused by the non-atomic update of the address/data pair.
 	 *
 	 * Direct update is possible when:
 	 * - The MSI is maskable (remapped MSI does not use this code path)).
 	 *   The quirk bit is not set in this case.
 	 * - The new vector is the same as the old vector
 	 * - The old vector is MANAGED_IRQ_SHUTDOWN_VECTOR (interrupt starts up)
 	 * - The interrupt is not yet started up
 	 * - The new destination CPU is the same as the old destination CPU
 	 */
 	if (!irqd_msi_nomask_quirk(irqd) ||
 	    cfg->vector == old_cfg.vector ||
 	    old_cfg.vector == MANAGED_IRQ_SHUTDOWN_VECTOR ||
 	    !irqd_is_started(irqd) ||
 	    cfg->dest_apicid == old_cfg.dest_apicid) {
 		irq_msi_update_msg(irqd, cfg);
 		return ret;
 	}

 	/*
 	 * Paranoia: Validate that the interrupt target is the local
 	 * CPU.
 	 */
 	if (WARN_ON_ONCE(cpu != smp_processor_id())) {
 		irq_msi_update_msg(irqd, cfg);
 		return ret;
 	}

 	/*
 	 * Redirect the interrupt to the new vector on the current CPU
 	 * first. This might cause a spurious interrupt on this vector if
 	 * the device raises an interrupt right between this update and the
 	 * update to the final destination CPU.
 	 *
 	 * If the vector is in use then the installed device handler will
 	 * denote it as spurious which is no harm as this is a rare event
 	 * and interrupt handlers have to cope with spurious interrupts
 	 * anyway. If the vector is unused, then it is marked so it won't
 	 * trigger the 'No irq handler for vector' warning in
 	 * common_interrupt().
 	 *
 	 * This requires to hold vector lock to prevent concurrent updates to
 	 * the affected vector.
 	 */
 	lock_vector_lock();

 	/*
 	 * Mark the new target vector on the local CPU if it is currently
 	 * unused. Reuse the VECTOR_RETRIGGERED state which is also used in
 	 * the CPU hotplug path for a similar purpose. This cannot be
 	 * undone here as the current CPU has interrupts disabled and
 	 * cannot handle the interrupt before the whole set_affinity()
 	 * section is done. In the CPU unplug case, the current CPU is
 	 * about to vanish and will not handle any interrupts anymore. The
 	 * vector is cleaned up when the CPU comes online again.
 	 */
 	if (IS_ERR_OR_NULL(this_cpu_read(vector_irq[cfg->vector])))
 		this_cpu_write(vector_irq[cfg->vector], VECTOR_RETRIGGERED);

 	/* Redirect it to the new vector on the local CPU temporarily */
 	old_cfg.vector = cfg->vector;
 	irq_msi_update_msg(irqd, &old_cfg);

 	/* Now transition it to the target CPU */
 	irq_msi_update_msg(irqd, cfg);

 	/*
 	 * All interrupts after this point are now targeted at the new
 	 * vector/CPU.
 	 *
 	 * Drop vector lock before testing whether the temporary assignment
 	 * to the local CPU was hit by an interrupt raised in the device,
 	 * because the retrigger function acquires vector lock again.
 	 */
 	unlock_vector_lock();

 	/*
 	 * Check whether the transition raced with a device interrupt and
 	 * is pending in the local APICs IRR. It is safe to do this outside
 	 * of vector lock as the irq_desc::lock of this interrupt is still
 	 * held and interrupts are disabled: The check is not accessing the
 	 * underlying vector store. It's just checking the local APIC's
 	 * IRR.
 	 */
 	if (lapic_vector_set_in_irr(cfg->vector))
 		irq_data_get_irq_chip(irqd)->irq_retrigger(irqd);

 	return ret;
 }

 /*
  * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
  * which implement the MSI or MSI-X Capability Structure.
  */
 static struct irq_chip pci_msi_controller = {
 	.name			= "PCI-MSI",
 	.irq_unmask		= pci_msi_unmask_irq,
 	.irq_mask		= pci_msi_mask_irq,
 	.irq_ack		= irq_chip_ack_parent,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_set_affinity	= msi_set_affinity,
 	.flags			= IRQCHIP_SKIP_SET_WAKE |
 				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };

 int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
 		    msi_alloc_info_t *arg)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct msi_desc *desc = first_pci_msi_entry(pdev);

 	init_irq_alloc_info(arg, NULL);
 	if (desc->msi_attrib.is_msix) {
 		arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSIX;
 	} else {
 		arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSI;
 		arg->flags |= X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(pci_msi_prepare);

 static struct msi_domain_ops pci_msi_domain_ops = {
 	.msi_prepare	= pci_msi_prepare,
 };

 static struct msi_domain_info pci_msi_domain_info = {
 	.flags		= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
 			  MSI_FLAG_PCI_MSIX,
 	.ops		= &pci_msi_domain_ops,
 	.chip		= &pci_msi_controller,
 	.handler	= handle_edge_irq,
 	.handler_name	= "edge",
 };

 struct irq_domain * __init native_create_pci_msi_domain(void)
 {
 	struct fwnode_handle *fn;
 	struct irq_domain *d;

 	if (disable_apic)
 		return NULL;

 	fn = irq_domain_alloc_named_fwnode("PCI-MSI");
 	if (!fn)
 		return NULL;

 	d = pci_msi_create_irq_domain(fn, &pci_msi_domain_info,
 				      x86_vector_domain);
 	if (!d) {
 		irq_domain_free_fwnode(fn);
 		pr_warn("Failed to initialize PCI-MSI irqdomain.\n");
 	} else {
 		d->flags |= IRQ_DOMAIN_MSI_NOMASK_QUIRK;
 	}
 	return d;
 }

 void __init x86_create_pci_msi_domain(void)
 {
 	x86_pci_msi_default_domain = x86_init.irqs.create_pci_msi_domain();
 }

 #ifdef CONFIG_IRQ_REMAP
 static struct irq_chip pci_msi_ir_controller = {
 	.name			= "IR-PCI-MSI",
 	.irq_unmask		= pci_msi_unmask_irq,
 	.irq_mask		= pci_msi_mask_irq,
 	.irq_ack		= irq_chip_ack_parent,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.flags			= IRQCHIP_SKIP_SET_WAKE |
 				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };

 static struct msi_domain_info pci_msi_ir_domain_info = {
 	.flags		= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
 			  MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX,
 	.ops		= &pci_msi_domain_ops,
 	.chip		= &pci_msi_ir_controller,
 	.handler	= handle_edge_irq,
 	.handler_name	= "edge",
 };

 struct irq_domain *arch_create_remap_msi_irq_domain(struct irq_domain *parent,
 						    const char *name, int id)
 {
 	struct fwnode_handle *fn;
 	struct irq_domain *d;

 	fn = irq_domain_alloc_named_id_fwnode(name, id);
 	if (!fn)
 		return NULL;
 	d = pci_msi_create_irq_domain(fn, &pci_msi_ir_domain_info, parent);
 	if (!d)
 		irq_domain_free_fwnode(fn);
 	return d;
 }
 #endif

 #ifdef CONFIG_DMAR_TABLE
 /*
  * The Intel IOMMU (ab)uses the high bits of the MSI address to contain the
  * high bits of the destination APIC ID. This can't be done in the general
  * case for MSIs as it would be targeting real memory above 4GiB not the
  * APIC.
  */
 static void dmar_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	__irq_msi_compose_msg(irqd_cfg(data), msg, true);
 }

 static void dmar_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	dmar_msi_write(data->irq, msg);
 }

 static struct irq_chip dmar_msi_controller = {
 	.name			= "DMAR-MSI",
 	.irq_unmask		= dmar_msi_unmask,
 	.irq_mask		= dmar_msi_mask,
 	.irq_ack		= irq_chip_ack_parent,
 	.irq_set_affinity	= msi_domain_set_affinity,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_compose_msi_msg	= dmar_msi_compose_msg,
 	.irq_write_msi_msg	= dmar_msi_write_msg,
 	.flags			= IRQCHIP_SKIP_SET_WAKE |
 				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };

 static int dmar_msi_init(struct irq_domain *domain,
 			 struct msi_domain_info *info, unsigned int virq,
 			 irq_hw_number_t hwirq, msi_alloc_info_t *arg)
 {
 	irq_domain_set_info(domain, virq, arg->devid, info->chip, NULL,
 			    handle_edge_irq, arg->data, "edge");

 	return 0;
 }

 static struct msi_domain_ops dmar_msi_domain_ops = {
 	.msi_init	= dmar_msi_init,
 };

 static struct msi_domain_info dmar_msi_domain_info = {
 	.ops		= &dmar_msi_domain_ops,
 	.chip		= &dmar_msi_controller,
 	.flags		= MSI_FLAG_USE_DEF_DOM_OPS,
 };

 static struct irq_domain *dmar_get_irq_domain(void)
 {
 	static struct irq_domain *dmar_domain;
 	static DEFINE_MUTEX(dmar_lock);
 	struct fwnode_handle *fn;

 	mutex_lock(&dmar_lock);
 	if (dmar_domain)
 		goto out;

 	fn = irq_domain_alloc_named_fwnode("DMAR-MSI");
 	if (fn) {
 		dmar_domain = msi_create_irq_domain(fn, &dmar_msi_domain_info,
 						    x86_vector_domain);
 		if (!dmar_domain)
 			irq_domain_free_fwnode(fn);
 	}
 out:
 	mutex_unlock(&dmar_lock);
 	return dmar_domain;
 }

 int dmar_alloc_hwirq(int id, int node, void *arg)
 {
 	struct irq_domain *domain = dmar_get_irq_domain();
 	struct irq_alloc_info info;

 	if (!domain)
 		return -1;

 	init_irq_alloc_info(&info, NULL);
 	info.type = X86_IRQ_ALLOC_TYPE_DMAR;
 	info.devid = id;
 	info.hwirq = id;
 	info.data = arg;

 	return irq_domain_alloc_irqs(domain, 1, node, &info);
 }

 void dmar_free_hwirq(int irq)
 {
 	irq_domain_free_irqs(irq, 1);
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Support of MSI, HPET and DMAR interrupts.
	*
	* Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
	* Moved from arch/x86/kernel/apic/io_apic.c.
	* Jiang Liu <jiang.liu@linux.intel.com>
	* Convert to hierarchical irqdomain
	*/
	#include <linux/mm.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/pci.h>
	#include <linux/dmar.h>
	#include <linux/hpet.h>
	#include <linux/msi.h>
	#include <asm/irqdomain.h>
	#include <asm/hpet.h>
	#include <asm/hw_irq.h>
	#include <asm/apic.h>
	#include <asm/irq_remapping.h>

	struct irq_domain *x86_pci_msi_default_domain __ro_after_init;

	static void irq_msi_update_msg(struct irq_data irqd, struct irq_cfg cfg)
	{
	struct msi_msg msg[2] = { [1] = { }, };

	__irq_msi_compose_msg(cfg, msg, false);
	irq_data_get_irq_chip(irqd)->irq_write_msi_msg(irqd, msg);
	}

	static int
	msi_set_affinity(struct irq_data irqd, const struct cpumask mask, bool force)
	{
	struct irq_cfg old_cfg, *cfg = irqd_cfg(irqd);
	struct irq_data *parent = irqd->parent_data;
	unsigned int cpu;
	int ret;

	/* Save the current configuration */
	cpu = cpumask_first(irq_data_get_effective_affinity_mask(irqd));
	old_cfg = *cfg;

	/* Allocate a new target vector */
	ret = parent->chip->irq_set_affinity(parent, mask, force);
	if (ret < 0 \|\| ret == IRQ_SET_MASK_OK_DONE)
	return ret;

	/*
	* For non-maskable and non-remapped MSI interrupts the migration
	* to a different destination CPU and a different vector has to be
	* done careful to handle the possible stray interrupt which can be
	* caused by the non-atomic update of the address/data pair.
	*
	* Direct update is possible when:
	* - The MSI is maskable (remapped MSI does not use this code path)).
	* The quirk bit is not set in this case.
	* - The new vector is the same as the old vector
	* - The old vector is MANAGED_IRQ_SHUTDOWN_VECTOR (interrupt starts up)
	* - The interrupt is not yet started up
	* - The new destination CPU is the same as the old destination CPU
	*/
	if (!irqd_msi_nomask_quirk(irqd) \|\|
	cfg->vector == old_cfg.vector \|\|
	old_cfg.vector == MANAGED_IRQ_SHUTDOWN_VECTOR \|\|
	!irqd_is_started(irqd) \|\|
	cfg->dest_apicid == old_cfg.dest_apicid) {
	irq_msi_update_msg(irqd, cfg);
	return ret;
	}

	/*
	* Paranoia: Validate that the interrupt target is the local
	* CPU.
	*/
	if (WARN_ON_ONCE(cpu != smp_processor_id())) {
	irq_msi_update_msg(irqd, cfg);
	return ret;
	}

	/*
	* Redirect the interrupt to the new vector on the current CPU
	* first. This might cause a spurious interrupt on this vector if
	* the device raises an interrupt right between this update and the
	* update to the final destination CPU.
	*
	* If the vector is in use then the installed device handler will
	* denote it as spurious which is no harm as this is a rare event
	* and interrupt handlers have to cope with spurious interrupts
	* anyway. If the vector is unused, then it is marked so it won't
	* trigger the 'No irq handler for vector' warning in
	* common_interrupt().
	*
	* This requires to hold vector lock to prevent concurrent updates to
	* the affected vector.
	*/
	lock_vector_lock();

	/*
	* Mark the new target vector on the local CPU if it is currently
	* unused. Reuse the VECTOR_RETRIGGERED state which is also used in
	* the CPU hotplug path for a similar purpose. This cannot be
	* undone here as the current CPU has interrupts disabled and
	* cannot handle the interrupt before the whole set_affinity()
	* section is done. In the CPU unplug case, the current CPU is
	* about to vanish and will not handle any interrupts anymore. The
	* vector is cleaned up when the CPU comes online again.
	*/
	if (IS_ERR_OR_NULL(this_cpu_read(vector_irq[cfg->vector])))
	this_cpu_write(vector_irq[cfg->vector], VECTOR_RETRIGGERED);

	/* Redirect it to the new vector on the local CPU temporarily */
	old_cfg.vector = cfg->vector;
	irq_msi_update_msg(irqd, &old_cfg);

	/* Now transition it to the target CPU */
	irq_msi_update_msg(irqd, cfg);

	/*
	* All interrupts after this point are now targeted at the new
	* vector/CPU.
	*
	* Drop vector lock before testing whether the temporary assignment
	* to the local CPU was hit by an interrupt raised in the device,
	* because the retrigger function acquires vector lock again.
	*/
	unlock_vector_lock();

	/*
	* Check whether the transition raced with a device interrupt and
	* is pending in the local APICs IRR. It is safe to do this outside
	* of vector lock as the irq_desc::lock of this interrupt is still
	* held and interrupts are disabled: The check is not accessing the
	* underlying vector store. It's just checking the local APIC's
	* IRR.
	*/
	if (lapic_vector_set_in_irr(cfg->vector))
	irq_data_get_irq_chip(irqd)->irq_retrigger(irqd);

	return ret;
	}

	/*
	* IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
	* which implement the MSI or MSI-X Capability Structure.
	*/
	static struct irq_chip pci_msi_controller = {
	.name = "PCI-MSI",
	.irq_unmask = pci_msi_unmask_irq,
	.irq_mask = pci_msi_mask_irq,
	.irq_ack = irq_chip_ack_parent,
	.irq_retrigger = irq_chip_retrigger_hierarchy,
	.irq_set_affinity = msi_set_affinity,
	.flags = IRQCHIP_SKIP_SET_WAKE \|
	IRQCHIP_AFFINITY_PRE_STARTUP,
	};

	int pci_msi_prepare(struct irq_domain domain, struct device dev, int nvec,
	msi_alloc_info_t *arg)
	{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct msi_desc *desc = first_pci_msi_entry(pdev);

	init_irq_alloc_info(arg, NULL);
	if (desc->msi_attrib.is_msix) {
	arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSIX;
	} else {
	arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSI;
	arg->flags \|= X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(pci_msi_prepare);

	static struct msi_domain_ops pci_msi_domain_ops = {
	.msi_prepare = pci_msi_prepare,
	};

	static struct msi_domain_info pci_msi_domain_info = {
	.flags = MSI_FLAG_USE_DEF_DOM_OPS \| MSI_FLAG_USE_DEF_CHIP_OPS \|
	MSI_FLAG_PCI_MSIX,
	.ops = &pci_msi_domain_ops,
	.chip = &pci_msi_controller,
	.handler = handle_edge_irq,
	.handler_name = "edge",
	};

	struct irq_domain * __init native_create_pci_msi_domain(void)
	{
	struct fwnode_handle *fn;
	struct irq_domain *d;

	if (disable_apic)
	return NULL;

	fn = irq_domain_alloc_named_fwnode("PCI-MSI");
	if (!fn)
	return NULL;

	d = pci_msi_create_irq_domain(fn, &pci_msi_domain_info,
	x86_vector_domain);
	if (!d) {
	irq_domain_free_fwnode(fn);
	pr_warn("Failed to initialize PCI-MSI irqdomain.\n");
	} else {
	d->flags \|= IRQ_DOMAIN_MSI_NOMASK_QUIRK;
	}
	return d;
	}

	void __init x86_create_pci_msi_domain(void)
	{
	x86_pci_msi_default_domain = x86_init.irqs.create_pci_msi_domain();
	}

	#ifdef CONFIG_IRQ_REMAP
	static struct irq_chip pci_msi_ir_controller = {
	.name = "IR-PCI-MSI",
	.irq_unmask = pci_msi_unmask_irq,
	.irq_mask = pci_msi_mask_irq,
	.irq_ack = irq_chip_ack_parent,
	.irq_retrigger = irq_chip_retrigger_hierarchy,
	.flags = IRQCHIP_SKIP_SET_WAKE \|
	IRQCHIP_AFFINITY_PRE_STARTUP,
	};

	static struct msi_domain_info pci_msi_ir_domain_info = {
	.flags = MSI_FLAG_USE_DEF_DOM_OPS \| MSI_FLAG_USE_DEF_CHIP_OPS \|
	MSI_FLAG_MULTI_PCI_MSI \| MSI_FLAG_PCI_MSIX,
	.ops = &pci_msi_domain_ops,
	.chip = &pci_msi_ir_controller,
	.handler = handle_edge_irq,
	.handler_name = "edge",
	};

	struct irq_domain arch_create_remap_msi_irq_domain(struct irq_domain parent,
	const char *name, int id)
	{
	struct fwnode_handle *fn;
	struct irq_domain *d;

	fn = irq_domain_alloc_named_id_fwnode(name, id);
	if (!fn)
	return NULL;
	d = pci_msi_create_irq_domain(fn, &pci_msi_ir_domain_info, parent);
	if (!d)
	irq_domain_free_fwnode(fn);
	return d;
	}
	#endif

	#ifdef CONFIG_DMAR_TABLE
	/*
	* The Intel IOMMU (ab)uses the high bits of the MSI address to contain the
	* high bits of the destination APIC ID. This can't be done in the general
	* case for MSIs as it would be targeting real memory above 4GiB not the
	* APIC.
	*/
	static void dmar_msi_compose_msg(struct irq_data data, struct msi_msg msg)
	{
	__irq_msi_compose_msg(irqd_cfg(data), msg, true);
	}

	static void dmar_msi_write_msg(struct irq_data data, struct msi_msg msg)
	{
	dmar_msi_write(data->irq, msg);
	}

	static struct irq_chip dmar_msi_controller = {
	.name = "DMAR-MSI",
	.irq_unmask = dmar_msi_unmask,
	.irq_mask = dmar_msi_mask,
	.irq_ack = irq_chip_ack_parent,
	.irq_set_affinity = msi_domain_set_affinity,
	.irq_retrigger = irq_chip_retrigger_hierarchy,
	.irq_compose_msi_msg = dmar_msi_compose_msg,
	.irq_write_msi_msg = dmar_msi_write_msg,
	.flags = IRQCHIP_SKIP_SET_WAKE \|
	IRQCHIP_AFFINITY_PRE_STARTUP,
	};

	static int dmar_msi_init(struct irq_domain *domain,
	struct msi_domain_info *info, unsigned int virq,
	irq_hw_number_t hwirq, msi_alloc_info_t *arg)
	{
	irq_domain_set_info(domain, virq, arg->devid, info->chip, NULL,
	handle_edge_irq, arg->data, "edge");

	return 0;
	}

	static struct msi_domain_ops dmar_msi_domain_ops = {
	.msi_init = dmar_msi_init,
	};

	static struct msi_domain_info dmar_msi_domain_info = {
	.ops = &dmar_msi_domain_ops,
	.chip = &dmar_msi_controller,
	.flags = MSI_FLAG_USE_DEF_DOM_OPS,
	};

	static struct irq_domain *dmar_get_irq_domain(void)
	{
	static struct irq_domain *dmar_domain;
	static DEFINE_MUTEX(dmar_lock);
	struct fwnode_handle *fn;

	mutex_lock(&dmar_lock);
	if (dmar_domain)
	goto out;

	fn = irq_domain_alloc_named_fwnode("DMAR-MSI");
	if (fn) {
	dmar_domain = msi_create_irq_domain(fn, &dmar_msi_domain_info,
	x86_vector_domain);
	if (!dmar_domain)
	irq_domain_free_fwnode(fn);
	}
	out:
	mutex_unlock(&dmar_lock);
	return dmar_domain;
	}

	int dmar_alloc_hwirq(int id, int node, void *arg)
	{
	struct irq_domain *domain = dmar_get_irq_domain();
	struct irq_alloc_info info;

	if (!domain)
	return -1;

	init_irq_alloc_info(&info, NULL);
	info.type = X86_IRQ_ALLOC_TYPE_DMAR;
	info.devid = id;
	info.hwirq = id;
	info.data = arg;

	return irq_domain_alloc_irqs(domain, 1, node, &info);
	}

	void dmar_free_hwirq(int irq)
	{
	irq_domain_free_irqs(irq, 1);
	}
	#endif