drivers/iommu/s390-iommu.c - SHIFTPHONES/mainline/linux - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * IOMMU API for s390 PCI devices
  *
  * Copyright IBM Corp. 2015
  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
  */

 #include <linux/pci.h>
 #include <linux/iommu.h>
 #include <linux/iommu-helper.h>
 #include <linux/sizes.h>
 #include <asm/pci_dma.h>

 /*
  * Physically contiguous memory regions can be mapped with 4 KiB alignment,
  * we allow all page sizes that are an order of 4KiB (no special large page
  * support so far).
  */
 #define S390_IOMMU_PGSIZES	(~0xFFFUL)

 static const struct iommu_ops s390_iommu_ops;

 struct s390_domain {
 	struct iommu_domain	domain;
 	struct list_head	devices;
 	unsigned long		*dma_table;
 	spinlock_t		dma_table_lock;
 	spinlock_t		list_lock;
 };

 struct s390_domain_device {
 	struct list_head	list;
 	struct zpci_dev		*zdev;
 };

 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct s390_domain, domain);
 }

 static bool s390_iommu_capable(enum iommu_cap cap)
 {
 	switch (cap) {
 	case IOMMU_CAP_CACHE_COHERENCY:
 		return true;
 	case IOMMU_CAP_INTR_REMAP:
 		return true;
 	default:
 		return false;
 	}
 }

 static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
 {
 	struct s390_domain *s390_domain;

 	if (domain_type != IOMMU_DOMAIN_UNMANAGED)
 		return NULL;

 	s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
 	if (!s390_domain)
 		return NULL;

 	s390_domain->dma_table = dma_alloc_cpu_table();
 	if (!s390_domain->dma_table) {
 		kfree(s390_domain);
 		return NULL;
 	}

 	spin_lock_init(&s390_domain->dma_table_lock);
 	spin_lock_init(&s390_domain->list_lock);
 	INIT_LIST_HEAD(&s390_domain->devices);

 	return &s390_domain->domain;
 }

 static void s390_domain_free(struct iommu_domain *domain)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);

 	dma_cleanup_tables(s390_domain->dma_table);
 	kfree(s390_domain);
 }

 static int s390_iommu_attach_device(struct iommu_domain *domain,
 				    struct device *dev)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev = to_zpci_dev(dev);
 	struct s390_domain_device *domain_device;
 	unsigned long flags;
 	int cc, rc;

 	if (!zdev)
 		return -ENODEV;

 	domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
 	if (!domain_device)
 		return -ENOMEM;

 	if (zdev->dma_table) {
 		cc = zpci_dma_exit_device(zdev);
 		if (cc) {
 			rc = -EIO;
 			goto out_free;
 		}
 	}

 	zdev->dma_table = s390_domain->dma_table;
 	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 				virt_to_phys(zdev->dma_table));
 	if (cc) {
 		rc = -EIO;
 		goto out_restore;
 	}

 	spin_lock_irqsave(&s390_domain->list_lock, flags);
 	/* First device defines the DMA range limits */
 	if (list_empty(&s390_domain->devices)) {
 		domain->geometry.aperture_start = zdev->start_dma;
 		domain->geometry.aperture_end = zdev->end_dma;
 		domain->geometry.force_aperture = true;
 	/* Allow only devices with identical DMA range limits */
 	} else if (domain->geometry.aperture_start != zdev->start_dma ||
 		   domain->geometry.aperture_end != zdev->end_dma) {
 		rc = -EINVAL;
 		spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 		goto out_restore;
 	}
 	domain_device->zdev = zdev;
 	zdev->s390_domain = s390_domain;
 	list_add(&domain_device->list, &s390_domain->devices);
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);

 	return 0;

 out_restore:
 	zpci_dma_init_device(zdev);
 out_free:
 	kfree(domain_device);

 	return rc;
 }

 static void s390_iommu_detach_device(struct iommu_domain *domain,
 				     struct device *dev)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev = to_zpci_dev(dev);
 	struct s390_domain_device *domain_device, *tmp;
 	unsigned long flags;
 	int found = 0;

 	if (!zdev)
 		return;

 	spin_lock_irqsave(&s390_domain->list_lock, flags);
 	list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 				 list) {
 		if (domain_device->zdev == zdev) {
 			list_del(&domain_device->list);
 			kfree(domain_device);
 			found = 1;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);

 	if (found) {
 		zdev->s390_domain = NULL;
 		zpci_unregister_ioat(zdev, 0);
 		zpci_dma_init_device(zdev);
 	}
 }

 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 {
 	struct zpci_dev *zdev = to_zpci_dev(dev);

 	return &zdev->iommu_dev;
 }

 static void s390_iommu_release_device(struct device *dev)
 {
 	struct zpci_dev *zdev = to_zpci_dev(dev);
 	struct iommu_domain *domain;

 	/*
 	 * This is a workaround for a scenario where the IOMMU API common code
 	 * "forgets" to call the detach_dev callback: After binding a device
 	 * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 	 * the attach_dev), removing the device via
 	 * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 	 * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 	 * notifier.
 	 *
 	 * So let's call detach_dev from here if it hasn't been called before.
 	 */
 	if (zdev && zdev->s390_domain) {
 		domain = iommu_get_domain_for_dev(dev);
 		if (domain)
 			s390_iommu_detach_device(domain, dev);
 	}
 }

 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 				   phys_addr_t pa, dma_addr_t dma_addr,
 				   size_t size, int flags)
 {
 	struct s390_domain_device *domain_device;
 	phys_addr_t page_addr = pa & PAGE_MASK;
 	dma_addr_t start_dma_addr = dma_addr;
 	unsigned long irq_flags, nr_pages, i;
 	unsigned long *entry;
 	int rc = 0;

 	if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 	    dma_addr + size > s390_domain->domain.geometry.aperture_end)
 		return -EINVAL;

 	nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	if (!nr_pages)
 		return 0;

 	spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 	for (i = 0; i < nr_pages; i++) {
 		entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 		if (!entry) {
 			rc = -ENOMEM;
 			goto undo_cpu_trans;
 		}
 		dma_update_cpu_trans(entry, page_addr, flags);
 		page_addr += PAGE_SIZE;
 		dma_addr += PAGE_SIZE;
 	}

 	spin_lock(&s390_domain->list_lock);
 	list_for_each_entry(domain_device, &s390_domain->devices, list) {
 		rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 					start_dma_addr, nr_pages * PAGE_SIZE);
 		if (rc)
 			break;
 	}
 	spin_unlock(&s390_domain->list_lock);

 undo_cpu_trans:
 	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 		flags = ZPCI_PTE_INVALID;
 		while (i-- > 0) {
 			page_addr -= PAGE_SIZE;
 			dma_addr -= PAGE_SIZE;
 			entry = dma_walk_cpu_trans(s390_domain->dma_table,
 						   dma_addr);
 			if (!entry)
 				break;
 			dma_update_cpu_trans(entry, page_addr, flags);
 		}
 	}
 	spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);

 	return rc;
 }

 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 			  phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	int flags = ZPCI_PTE_VALID, rc = 0;

 	if (!(prot & IOMMU_READ))
 		return -EINVAL;

 	if (!(prot & IOMMU_WRITE))
 		flags |= ZPCI_TABLE_PROTECTED;

 	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 				     size, flags);

 	return rc;
 }

 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 					   dma_addr_t iova)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	unsigned long *sto, *pto, *rto, flags;
 	unsigned int rtx, sx, px;
 	phys_addr_t phys = 0;

 	if (iova < domain->geometry.aperture_start ||
 	    iova > domain->geometry.aperture_end)
 		return 0;

 	rtx = calc_rtx(iova);
 	sx = calc_sx(iova);
 	px = calc_px(iova);
 	rto = s390_domain->dma_table;

 	spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 	if (rto && reg_entry_isvalid(rto[rtx])) {
 		sto = get_rt_sto(rto[rtx]);
 		if (sto && reg_entry_isvalid(sto[sx])) {
 			pto = get_st_pto(sto[sx]);
 			if (pto && pt_entry_isvalid(pto[px]))
 				phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 		}
 	}
 	spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);

 	return phys;
 }

 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 			       unsigned long iova, size_t size,
 			       struct iommu_iotlb_gather *gather)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	int flags = ZPCI_PTE_INVALID;
 	phys_addr_t paddr;
 	int rc;

 	paddr = s390_iommu_iova_to_phys(domain, iova);
 	if (!paddr)
 		return 0;

 	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 				     size, flags);
 	if (rc)
 		return 0;

 	return size;
 }

 int zpci_init_iommu(struct zpci_dev *zdev)
 {
 	int rc = 0;

 	rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 				    "s390-iommu.%08x", zdev->fid);
 	if (rc)
 		goto out_err;

 	rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
 	if (rc)
 		goto out_sysfs;

 	return 0;

 out_sysfs:
 	iommu_device_sysfs_remove(&zdev->iommu_dev);

 out_err:
 	return rc;
 }

 void zpci_destroy_iommu(struct zpci_dev *zdev)
 {
 	iommu_device_unregister(&zdev->iommu_dev);
 	iommu_device_sysfs_remove(&zdev->iommu_dev);
 }

 static const struct iommu_ops s390_iommu_ops = {
 	.capable = s390_iommu_capable,
 	.domain_alloc = s390_domain_alloc,
 	.domain_free = s390_domain_free,
 	.attach_dev = s390_iommu_attach_device,
 	.detach_dev = s390_iommu_detach_device,
 	.map = s390_iommu_map,
 	.unmap = s390_iommu_unmap,
 	.iova_to_phys = s390_iommu_iova_to_phys,
 	.probe_device = s390_iommu_probe_device,
 	.release_device = s390_iommu_release_device,
 	.device_group = generic_device_group,
 	.pgsize_bitmap = S390_IOMMU_PGSIZES,
 };

 static int __init s390_iommu_init(void)
 {
 	return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 }
 subsys_initcall(s390_iommu_init);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* IOMMU API for s390 PCI devices
	*
	* Copyright IBM Corp. 2015
	* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
	*/

	#include <linux/pci.h>
	#include <linux/iommu.h>
	#include <linux/iommu-helper.h>
	#include <linux/sizes.h>
	#include <asm/pci_dma.h>

	/*
	* Physically contiguous memory regions can be mapped with 4 KiB alignment,
	* we allow all page sizes that are an order of 4KiB (no special large page
	* support so far).
	*/
	#define S390_IOMMU_PGSIZES (~0xFFFUL)

	static const struct iommu_ops s390_iommu_ops;

	struct s390_domain {
	struct iommu_domain domain;
	struct list_head devices;
	unsigned long *dma_table;
	spinlock_t dma_table_lock;
	spinlock_t list_lock;
	};

	struct s390_domain_device {
	struct list_head list;
	struct zpci_dev *zdev;
	};

	static struct s390_domain to_s390_domain(struct iommu_domain dom)
	{
	return container_of(dom, struct s390_domain, domain);
	}

	static bool s390_iommu_capable(enum iommu_cap cap)
	{
	switch (cap) {
	case IOMMU_CAP_CACHE_COHERENCY:
	return true;
	case IOMMU_CAP_INTR_REMAP:
	return true;
	default:
	return false;
	}
	}

	static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
	{
	struct s390_domain *s390_domain;

	if (domain_type != IOMMU_DOMAIN_UNMANAGED)
	return NULL;

	s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
	if (!s390_domain)
	return NULL;

	s390_domain->dma_table = dma_alloc_cpu_table();
	if (!s390_domain->dma_table) {
	kfree(s390_domain);
	return NULL;
	}

	spin_lock_init(&s390_domain->dma_table_lock);
	spin_lock_init(&s390_domain->list_lock);
	INIT_LIST_HEAD(&s390_domain->devices);

	return &s390_domain->domain;
	}

	static void s390_domain_free(struct iommu_domain *domain)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);

	dma_cleanup_tables(s390_domain->dma_table);
	kfree(s390_domain);
	}

	static int s390_iommu_attach_device(struct iommu_domain *domain,
	struct device *dev)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct s390_domain_device *domain_device;
	unsigned long flags;
	int cc, rc;

	if (!zdev)
	return -ENODEV;

	domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
	if (!domain_device)
	return -ENOMEM;

	if (zdev->dma_table) {
	cc = zpci_dma_exit_device(zdev);
	if (cc) {
	rc = -EIO;
	goto out_free;
	}
	}

	zdev->dma_table = s390_domain->dma_table;
	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
	virt_to_phys(zdev->dma_table));
	if (cc) {
	rc = -EIO;
	goto out_restore;
	}

	spin_lock_irqsave(&s390_domain->list_lock, flags);
	/* First device defines the DMA range limits */
	if (list_empty(&s390_domain->devices)) {
	domain->geometry.aperture_start = zdev->start_dma;
	domain->geometry.aperture_end = zdev->end_dma;
	domain->geometry.force_aperture = true;
	/* Allow only devices with identical DMA range limits */
	} else if (domain->geometry.aperture_start != zdev->start_dma \|\|
	domain->geometry.aperture_end != zdev->end_dma) {
	rc = -EINVAL;
	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
	goto out_restore;
	}
	domain_device->zdev = zdev;
	zdev->s390_domain = s390_domain;
	list_add(&domain_device->list, &s390_domain->devices);
	spin_unlock_irqrestore(&s390_domain->list_lock, flags);

	return 0;

	out_restore:
	zpci_dma_init_device(zdev);
	out_free:
	kfree(domain_device);

	return rc;
	}

	static void s390_iommu_detach_device(struct iommu_domain *domain,
	struct device *dev)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct s390_domain_device domain_device, tmp;
	unsigned long flags;
	int found = 0;

	if (!zdev)
	return;

	spin_lock_irqsave(&s390_domain->list_lock, flags);
	list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
	list) {
	if (domain_device->zdev == zdev) {
	list_del(&domain_device->list);
	kfree(domain_device);
	found = 1;
	break;
	}
	}
	spin_unlock_irqrestore(&s390_domain->list_lock, flags);

	if (found) {
	zdev->s390_domain = NULL;
	zpci_unregister_ioat(zdev, 0);
	zpci_dma_init_device(zdev);
	}
	}

	static struct iommu_device s390_iommu_probe_device(struct device dev)
	{
	struct zpci_dev *zdev = to_zpci_dev(dev);

	return &zdev->iommu_dev;
	}

	static void s390_iommu_release_device(struct device *dev)
	{
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct iommu_domain *domain;

	/*
	* This is a workaround for a scenario where the IOMMU API common code
	* "forgets" to call the detach_dev callback: After binding a device
	* to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
	* the attach_dev), removing the device via
	* "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
	* only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
	* notifier.
	*
	* So let's call detach_dev from here if it hasn't been called before.
	*/
	if (zdev && zdev->s390_domain) {
	domain = iommu_get_domain_for_dev(dev);
	if (domain)
	s390_iommu_detach_device(domain, dev);
	}
	}

	static int s390_iommu_update_trans(struct s390_domain *s390_domain,
	phys_addr_t pa, dma_addr_t dma_addr,
	size_t size, int flags)
	{
	struct s390_domain_device *domain_device;
	phys_addr_t page_addr = pa & PAGE_MASK;
	dma_addr_t start_dma_addr = dma_addr;
	unsigned long irq_flags, nr_pages, i;
	unsigned long *entry;
	int rc = 0;

	if (dma_addr < s390_domain->domain.geometry.aperture_start \|\|
	dma_addr + size > s390_domain->domain.geometry.aperture_end)
	return -EINVAL;

	nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
	if (!nr_pages)
	return 0;

	spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
	for (i = 0; i < nr_pages; i++) {
	entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
	if (!entry) {
	rc = -ENOMEM;
	goto undo_cpu_trans;
	}
	dma_update_cpu_trans(entry, page_addr, flags);
	page_addr += PAGE_SIZE;
	dma_addr += PAGE_SIZE;
	}

	spin_lock(&s390_domain->list_lock);
	list_for_each_entry(domain_device, &s390_domain->devices, list) {
	rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
	start_dma_addr, nr_pages * PAGE_SIZE);
	if (rc)
	break;
	}
	spin_unlock(&s390_domain->list_lock);

	undo_cpu_trans:
	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
	flags = ZPCI_PTE_INVALID;
	while (i-- > 0) {
	page_addr -= PAGE_SIZE;
	dma_addr -= PAGE_SIZE;
	entry = dma_walk_cpu_trans(s390_domain->dma_table,
	dma_addr);
	if (!entry)
	break;
	dma_update_cpu_trans(entry, page_addr, flags);
	}
	}
	spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);

	return rc;
	}

	static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
	phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	int flags = ZPCI_PTE_VALID, rc = 0;

	if (!(prot & IOMMU_READ))
	return -EINVAL;

	if (!(prot & IOMMU_WRITE))
	flags \|= ZPCI_TABLE_PROTECTED;

	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
	size, flags);

	return rc;
	}

	static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
	dma_addr_t iova)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	unsigned long sto, pto, *rto, flags;
	unsigned int rtx, sx, px;
	phys_addr_t phys = 0;

	if (iova < domain->geometry.aperture_start \|\|
	iova > domain->geometry.aperture_end)
	return 0;

	rtx = calc_rtx(iova);
	sx = calc_sx(iova);
	px = calc_px(iova);
	rto = s390_domain->dma_table;

	spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
	if (rto && reg_entry_isvalid(rto[rtx])) {
	sto = get_rt_sto(rto[rtx]);
	if (sto && reg_entry_isvalid(sto[sx])) {
	pto = get_st_pto(sto[sx]);
	if (pto && pt_entry_isvalid(pto[px]))
	phys = pto[px] & ZPCI_PTE_ADDR_MASK;
	}
	}
	spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);

	return phys;
	}

	static size_t s390_iommu_unmap(struct iommu_domain *domain,
	unsigned long iova, size_t size,
	struct iommu_iotlb_gather *gather)
	{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	int flags = ZPCI_PTE_INVALID;
	phys_addr_t paddr;
	int rc;

	paddr = s390_iommu_iova_to_phys(domain, iova);
	if (!paddr)
	return 0;

	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
	size, flags);
	if (rc)
	return 0;

	return size;
	}

	int zpci_init_iommu(struct zpci_dev *zdev)
	{
	int rc = 0;

	rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
	"s390-iommu.%08x", zdev->fid);
	if (rc)
	goto out_err;

	rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
	if (rc)
	goto out_sysfs;

	return 0;

	out_sysfs:
	iommu_device_sysfs_remove(&zdev->iommu_dev);

	out_err:
	return rc;
	}

	void zpci_destroy_iommu(struct zpci_dev *zdev)
	{
	iommu_device_unregister(&zdev->iommu_dev);
	iommu_device_sysfs_remove(&zdev->iommu_dev);
	}

	static const struct iommu_ops s390_iommu_ops = {
	.capable = s390_iommu_capable,
	.domain_alloc = s390_domain_alloc,
	.domain_free = s390_domain_free,
	.attach_dev = s390_iommu_attach_device,
	.detach_dev = s390_iommu_detach_device,
	.map = s390_iommu_map,
	.unmap = s390_iommu_unmap,
	.iova_to_phys = s390_iommu_iova_to_phys,
	.probe_device = s390_iommu_probe_device,
	.release_device = s390_iommu_release_device,
	.device_group = generic_device_group,
	.pgsize_bitmap = S390_IOMMU_PGSIZES,
	};

	static int __init s390_iommu_init(void)
	{
	return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
	}
	subsys_initcall(s390_iommu_init);