kernel / drivers / iommu / s390-iommu.c

// SPDX-License-Identifier: GPL-2.0
/*
 * IOMMU API for s390 PCI devices
 *
 * Copyright IBM Corp. 2015
 * Author(s): Gerald Schaefer <[e-mail]>
 */

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

#include "dma-iommu.h"

static const struct iommu_ops s390_iommu_ops, s390_iommu_rtr_ops;

static struct kmem_cache *dma_region_table_cache;
static struct kmem_cache *dma_page_table_cache;

static u64 s390_iommu_aperture;
static u32 s390_iommu_aperture_factor = 1;

struct s390_domain {
	struct iommu_domain	domain;
	struct list_head	devices;
	struct zpci_iommu_ctrs	ctrs;
	unsigned long		*dma_table;
	spinlock_t		list_lock;
	struct rcu_head		rcu;
	u8			origin_type;
};

static struct iommu_domain blocking_domain;

static inline unsigned int calc_rfx(dma_addr_t ptr)
{
	return ((unsigned long)ptr >> ZPCI_RF_SHIFT) & ZPCI_INDEX_MASK;
}

static inline unsigned int calc_rsx(dma_addr_t ptr)
{
	return ((unsigned long)ptr >> ZPCI_RS_SHIFT) & ZPCI_INDEX_MASK;
}

static inline unsigned int calc_rtx(dma_addr_t ptr)
{
	return ((unsigned long)ptr >> ZPCI_RT_SHIFT) & ZPCI_INDEX_MASK;
}

static inline unsigned int calc_sx(dma_addr_t ptr)
{
	return ((unsigned long)ptr >> ZPCI_ST_SHIFT) & ZPCI_INDEX_MASK;
}

static inline unsigned int calc_px(dma_addr_t ptr)
{
	return ((unsigned long)ptr >> PAGE_SHIFT) & ZPCI_PT_MASK;
}

static inline void set_pt_pfaa(unsigned long *entry, phys_addr_t pfaa)
{
	*entry &= ZPCI_PTE_FLAG_MASK;
	*entry |= (pfaa & ZPCI_PTE_ADDR_MASK);
}

static inline void set_rf_rso(unsigned long *entry, phys_addr_t rso)
{
	*entry &= ZPCI_RTE_FLAG_MASK;
	*entry |= (rso & ZPCI_RTE_ADDR_MASK);
	*entry |= ZPCI_TABLE_TYPE_RFX;
}

static inline void set_rs_rto(unsigned long *entry, phys_addr_t rto)
{
	*entry &= ZPCI_RTE_FLAG_MASK;
	*entry |= (rto & ZPCI_RTE_ADDR_MASK);
	*entry |= ZPCI_TABLE_TYPE_RSX;
}

static inline void set_rt_sto(unsigned long *entry, phys_addr_t sto)
{
	*entry &= ZPCI_RTE_FLAG_MASK;
	*entry |= (sto & ZPCI_RTE_ADDR_MASK);
	*entry |= ZPCI_TABLE_TYPE_RTX;
}

static inline void set_st_pto(unsigned long *entry, phys_addr_t pto)
{
	*entry &= ZPCI_STE_FLAG_MASK;
	*entry |= (pto & ZPCI_STE_ADDR_MASK);
	*entry |= ZPCI_TABLE_TYPE_SX;
}

static inline void validate_rf_entry(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_VALID_MASK;
	*entry &= ~ZPCI_TABLE_OFFSET_MASK;
	*entry |= ZPCI_TABLE_VALID;
	*entry |= ZPCI_TABLE_LEN_RFX;
}

static inline void validate_rs_entry(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_VALID_MASK;
	*entry &= ~ZPCI_TABLE_OFFSET_MASK;
	*entry |= ZPCI_TABLE_VALID;
	*entry |= ZPCI_TABLE_LEN_RSX;
}

static inline void validate_rt_entry(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_VALID_MASK;
	*entry &= ~ZPCI_TABLE_OFFSET_MASK;
	*entry |= ZPCI_TABLE_VALID;
	*entry |= ZPCI_TABLE_LEN_RTX;
}

static inline void validate_st_entry(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_VALID_MASK;
	*entry |= ZPCI_TABLE_VALID;
}

static inline void invalidate_pt_entry(unsigned long *entry)
{
	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_INVALID);
	*entry &= ~ZPCI_PTE_VALID_MASK;
	*entry |= ZPCI_PTE_INVALID;
}

static inline void validate_pt_entry(unsigned long *entry)
{
	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID);
	*entry &= ~ZPCI_PTE_VALID_MASK;
	*entry |= ZPCI_PTE_VALID;
}

static inline void entry_set_protected(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_PROT_MASK;
	*entry |= ZPCI_TABLE_PROTECTED;
}

static inline void entry_clr_protected(unsigned long *entry)
{
	*entry &= ~ZPCI_TABLE_PROT_MASK;
	*entry |= ZPCI_TABLE_UNPROTECTED;
}

static inline int reg_entry_isvalid(unsigned long entry)
{
	return (entry & ZPCI_TABLE_VALID_MASK) == ZPCI_TABLE_VALID;
}

static inline int pt_entry_isvalid(unsigned long entry)
{
	return (entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID;
}

static inline unsigned long *get_rf_rso(unsigned long entry)
{
	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_RFX)
		return phys_to_virt(entry & ZPCI_RTE_ADDR_MASK);
	else
		return NULL;
}

static inline unsigned long *get_rs_rto(unsigned long entry)
{
	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_RSX)
		return phys_to_virt(entry & ZPCI_RTE_ADDR_MASK);
	else
		return NULL;
}

static inline unsigned long *get_rt_sto(unsigned long entry)
{
	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_RTX)
		return phys_to_virt(entry & ZPCI_RTE_ADDR_MASK);
	else
		return NULL;
}

static inline unsigned long *get_st_pto(unsigned long entry)
{
	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_SX)
		return phys_to_virt(entry & ZPCI_STE_ADDR_MASK);
	else
		return NULL;
}

static int __init dma_alloc_cpu_table_caches(void)
{
	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
						   ZPCI_TABLE_SIZE,
						   ZPCI_TABLE_ALIGN,
						   0, NULL);
	if (!dma_region_table_cache)
		return -ENOMEM;

	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
						 ZPCI_PT_SIZE,
						 ZPCI_PT_ALIGN,
						 0, NULL);
	if (!dma_page_table_cache) {
		kmem_cache_destroy(dma_region_table_cache);
		return -ENOMEM;
	}
	return 0;
}

static unsigned long *dma_alloc_cpu_table(gfp_t gfp)
{
	unsigned long *table, *entry;

	table = kmem_cache_alloc(dma_region_table_cache, gfp);
	if (!table)
		return NULL;

	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
		*entry = ZPCI_TABLE_INVALID;
	return table;
}

static void dma_free_cpu_table(void *table)
{
	kmem_cache_free(dma_region_table_cache, table);
}

static void dma_free_page_table(void *table)
{
	kmem_cache_free(dma_page_table_cache, table);
}

static void dma_free_seg_table(unsigned long entry)
{
	unsigned long *sto = get_rt_sto(entry);
	int sx;

	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
		if (reg_entry_isvalid(sto[sx]))
			dma_free_page_table(get_st_pto(sto[sx]));

	dma_free_cpu_table(sto);
}

static void dma_free_rt_table(unsigned long entry)
{
	unsigned long *rto = get_rs_rto(entry);
	int rtx;

	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
		if (reg_entry_isvalid(rto[rtx]))
			dma_free_seg_table(rto[rtx]);

	dma_free_cpu_table(rto);
}

static void dma_free_rs_table(unsigned long entry)
{
	unsigned long *rso = get_rf_rso(entry);
	int rsx;

	for (rsx = 0; rsx < ZPCI_TABLE_ENTRIES; rsx++)
		if (reg_entry_isvalid(rso[rsx]))
			dma_free_rt_table(rso[rsx]);

	dma_free_cpu_table(rso);
}

static void dma_cleanup_tables(struct s390_domain *domain)
{
	int rtx, rsx, rfx;

	if (!domain->dma_table)
		return;

	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RFX:
		for (rfx = 0; rfx < ZPCI_TABLE_ENTRIES; rfx++)
			if (reg_entry_isvalid(domain->dma_table[rfx]))
				dma_free_rs_table(domain->dma_table[rfx]);
		break;
	case ZPCI_TABLE_TYPE_RSX:
		for (rsx = 0; rsx < ZPCI_TABLE_ENTRIES; rsx++)
			if (reg_entry_isvalid(domain->dma_table[rsx]))
				dma_free_rt_table(domain->dma_table[rsx]);
		break;
	case ZPCI_TABLE_TYPE_RTX:
		for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
			if (reg_entry_isvalid(domain->dma_table[rtx]))
				dma_free_seg_table(domain->dma_table[rtx]);
		break;
	default:
		WARN_ONCE(1, "Invalid IOMMU table (%x)\n", domain->origin_type);
		return;
	}

	dma_free_cpu_table(domain->dma_table);
}

static unsigned long *dma_alloc_page_table(gfp_t gfp)
{
	unsigned long *table, *entry;

	table = kmem_cache_alloc(dma_page_table_cache, gfp);
	if (!table)
		return NULL;

	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
		*entry = ZPCI_PTE_INVALID;
	return table;
}

static unsigned long *dma_walk_rs_table(unsigned long *rso,
					dma_addr_t dma_addr, gfp_t gfp)
{
	unsigned int rsx = calc_rsx(dma_addr);
	unsigned long old_rse, rse;
	unsigned long *rsep, *rto;

	rsep = &rso[rsx];
	rse = READ_ONCE(*rsep);
	if (reg_entry_isvalid(rse)) {
		rto = get_rs_rto(rse);
	} else {
		rto = dma_alloc_cpu_table(gfp);
		if (!rto)
			return NULL;

		set_rs_rto(&rse, virt_to_phys(rto));
		validate_rs_entry(&rse);
		entry_clr_protected(&rse);

		old_rse = cmpxchg(rsep, ZPCI_TABLE_INVALID, rse);
		if (old_rse != ZPCI_TABLE_INVALID) {
			/* Somone else was faster, use theirs */
			dma_free_cpu_table(rto);
			rto = get_rs_rto(old_rse);
		}
	}
	return rto;
}

static unsigned long *dma_walk_rf_table(unsigned long *rfo,
					dma_addr_t dma_addr, gfp_t gfp)
{
	unsigned int rfx = calc_rfx(dma_addr);
	unsigned long old_rfe, rfe;
	unsigned long *rfep, *rso;

	rfep = &rfo[rfx];
	rfe = READ_ONCE(*rfep);
	if (reg_entry_isvalid(rfe)) {
		rso = get_rf_rso(rfe);
	} else {
		rso = dma_alloc_cpu_table(gfp);
		if (!rso)
			return NULL;

		set_rf_rso(&rfe, virt_to_phys(rso));
		validate_rf_entry(&rfe);
		entry_clr_protected(&rfe);

		old_rfe = cmpxchg(rfep, ZPCI_TABLE_INVALID, rfe);
		if (old_rfe != ZPCI_TABLE_INVALID) {
			/* Somone else was faster, use theirs */
			dma_free_cpu_table(rso);
			rso = get_rf_rso(old_rfe);
		}
	}

	if (!rso)
		return NULL;

	return dma_walk_rs_table(rso, dma_addr, gfp);
}

static unsigned long *dma_get_seg_table_origin(unsigned long *rtep, gfp_t gfp)
{
	unsigned long old_rte, rte;
	unsigned long *sto;

	rte = READ_ONCE(*rtep);
	if (reg_entry_isvalid(rte)) {
		sto = get_rt_sto(rte);
	} else {
		sto = dma_alloc_cpu_table(gfp);
		if (!sto)
			return NULL;

		set_rt_sto(&rte, virt_to_phys(sto));
		validate_rt_entry(&rte);
		entry_clr_protected(&rte);

		old_rte = cmpxchg(rtep, ZPCI_TABLE_INVALID, rte);
		if (old_rte != ZPCI_TABLE_INVALID) {
			/* Somone else was faster, use theirs */
			dma_free_cpu_table(sto);
			sto = get_rt_sto(old_rte);
		}
	}
	return sto;
}

static unsigned long *dma_get_page_table_origin(unsigned long *step, gfp_t gfp)
{
	unsigned long old_ste, ste;
	unsigned long *pto;

	ste = READ_ONCE(*step);
	if (reg_entry_isvalid(ste)) {
		pto = get_st_pto(ste);
	} else {
		pto = dma_alloc_page_table(gfp);
		if (!pto)
			return NULL;
		set_st_pto(&ste, virt_to_phys(pto));
		validate_st_entry(&ste);
		entry_clr_protected(&ste);

		old_ste = cmpxchg(step, ZPCI_TABLE_INVALID, ste);
		if (old_ste != ZPCI_TABLE_INVALID) {
			/* Somone else was faster, use theirs */
			dma_free_page_table(pto);
			pto = get_st_pto(old_ste);
		}
	}
	return pto;
}

static unsigned long *dma_walk_region_tables(struct s390_domain *domain,
					     dma_addr_t dma_addr, gfp_t gfp)
{
	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RFX:
		return dma_walk_rf_table(domain->dma_table, dma_addr, gfp);
	case ZPCI_TABLE_TYPE_RSX:
		return dma_walk_rs_table(domain->dma_table, dma_addr, gfp);
	case ZPCI_TABLE_TYPE_RTX:
		return domain->dma_table;
	default:
		return NULL;
	}
}

static unsigned long *dma_walk_cpu_trans(struct s390_domain *domain,
					 dma_addr_t dma_addr, gfp_t gfp)
{
	unsigned long *rto, *sto, *pto;
	unsigned int rtx, sx, px;

	rto = dma_walk_region_tables(domain, dma_addr, gfp);
	if (!rto)
		return NULL;

	rtx = calc_rtx(dma_addr);
	sto = dma_get_seg_table_origin(&rto[rtx], gfp);
	if (!sto)
		return NULL;

	sx = calc_sx(dma_addr);
	pto = dma_get_page_table_origin(&sto[sx], gfp);
	if (!pto)
		return NULL;

	px = calc_px(dma_addr);
	return &pto[px];
}

static void dma_update_cpu_trans(unsigned long *ptep, phys_addr_t page_addr, int flags)
{
	unsigned long pte;

	pte = READ_ONCE(*ptep);
	if (flags & ZPCI_PTE_INVALID) {
		invalidate_pt_entry(&pte);
	} else {
		set_pt_pfaa(&pte, page_addr);
		validate_pt_entry(&pte);
	}

	if (flags & ZPCI_TABLE_PROTECTED)
		entry_set_protected(&pte);
	else
		entry_clr_protected(&pte);

	xchg(ptep, pte);
}

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

static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
{
	struct zpci_dev *zdev = to_zpci_dev(dev);

	switch (cap) {
	case IOMMU_CAP_CACHE_COHERENCY:
		return true;
	case IOMMU_CAP_DEFERRED_FLUSH:
		return zdev->pft != PCI_FUNC_TYPE_ISM;
	default:
		return false;
	}
}

static inline u64 max_tbl_size(struct s390_domain *domain)
{
	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RTX:
		return ZPCI_TABLE_SIZE_RT - 1;
	case ZPCI_TABLE_TYPE_RSX:
		return ZPCI_TABLE_SIZE_RS - 1;
	case ZPCI_TABLE_TYPE_RFX:
		return U64_MAX;
	default:
		return 0;
	}
}

static struct iommu_domain *s390_domain_alloc_paging(struct device *dev)
{
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct s390_domain *s390_domain;
	u64 aperture_size;

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

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

	aperture_size = min(s390_iommu_aperture,
			    zdev->end_dma - zdev->start_dma + 1);
	if (aperture_size <= (ZPCI_TABLE_SIZE_RT - zdev->start_dma)) {
		s390_domain->origin_type = ZPCI_TABLE_TYPE_RTX;
	} else if (aperture_size <= (ZPCI_TABLE_SIZE_RS - zdev->start_dma) &&
		  (zdev->dtsm & ZPCI_IOTA_DT_RS)) {
		s390_domain->origin_type = ZPCI_TABLE_TYPE_RSX;
	} else if (zdev->dtsm & ZPCI_IOTA_DT_RF) {
		s390_domain->origin_type = ZPCI_TABLE_TYPE_RFX;
	} else {
		/* Assume RTX available */
		s390_domain->origin_type = ZPCI_TABLE_TYPE_RTX;
		aperture_size = ZPCI_TABLE_SIZE_RT - zdev->start_dma;
	}
	zdev->end_dma = zdev->start_dma + aperture_size - 1;

	s390_domain->domain.pgsize_bitmap = SZ_4K;
	s390_domain->domain.geometry.force_aperture = true;
	s390_domain->domain.geometry.aperture_start = 0;
	s390_domain->domain.geometry.aperture_end = max_tbl_size(s390_domain);

	spin_lock_init(&s390_domain->list_lock);
	INIT_LIST_HEAD_RCU(&s390_domain->devices);

	return &s390_domain->domain;
}

static void s390_iommu_rcu_free_domain(struct rcu_head *head)
{
	struct s390_domain *s390_domain = container_of(head, struct s390_domain, rcu);

	dma_cleanup_tables(s390_domain);
	kfree(s390_domain);
}

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

	rcu_read_lock();
	WARN_ON(!list_empty(&s390_domain->devices));
	rcu_read_unlock();

	call_rcu(&s390_domain->rcu, s390_iommu_rcu_free_domain);
}

static void zdev_s390_domain_update(struct zpci_dev *zdev,
				    struct iommu_domain *domain)
{
	unsigned long flags;

	spin_lock_irqsave(&zdev->dom_lock, flags);
	zdev->s390_domain = domain;
	spin_unlock_irqrestore(&zdev->dom_lock, flags);
}

static u64 get_iota_region_flag(struct s390_domain *domain)
{
	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RTX:
		return ZPCI_IOTA_RTTO_FLAG;
	case ZPCI_TABLE_TYPE_RSX:
		return ZPCI_IOTA_RSTO_FLAG;
	case ZPCI_TABLE_TYPE_RFX:
		return ZPCI_IOTA_RFTO_FLAG;
	default:
		WARN_ONCE(1, "Invalid IOMMU table (%x)\n", domain->origin_type);
		return 0;
	}
}

static bool reg_ioat_propagate_error(int cc, u8 status)
{
	/*
	 * If the device is in the error state the reset routine
	 * will register the IOAT of the newly set domain on re-enable
	 */
	if (cc == ZPCI_CC_ERR && status == ZPCI_PCI_ST_FUNC_NOT_AVAIL)
		return false;
	/*
	 * If the device was removed treat registration as success
	 * and let the subsequent error event trigger tear down.
	 */
	if (cc == ZPCI_CC_INVAL_HANDLE)
		return false;
	return cc != ZPCI_CC_OK;
}

static int s390_iommu_domain_reg_ioat(struct zpci_dev *zdev,
				      struct iommu_domain *domain, u8 *status)
{
	struct s390_domain *s390_domain;
	int rc = 0;
	u64 iota;

	switch (domain->type) {
	case IOMMU_DOMAIN_IDENTITY:
		rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
					zdev->end_dma, 0, status);
		break;
	case IOMMU_DOMAIN_BLOCKED:
		/* Nothing to do in this case */
		break;
	default:
		s390_domain = to_s390_domain(domain);
		iota = virt_to_phys(s390_domain->dma_table) |
		       get_iota_region_flag(s390_domain);
		rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
					zdev->end_dma, iota, status);
	}

	return rc;
}

int zpci_iommu_register_ioat(struct zpci_dev *zdev, u8 *status)
{
	unsigned long flags;
	int rc;

	spin_lock_irqsave(&zdev->dom_lock, flags);

	rc = s390_iommu_domain_reg_ioat(zdev, zdev->s390_domain, status);

	spin_unlock_irqrestore(&zdev->dom_lock, flags);

	return rc;
}

static int blocking_domain_attach_device(struct iommu_domain *domain,
					 struct device *dev,
					 struct iommu_domain *old)
{
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct s390_domain *s390_domain;
	unsigned long flags;

	if (zdev->s390_domain->type == IOMMU_DOMAIN_BLOCKED)
		return 0;

	s390_domain = to_s390_domain(zdev->s390_domain);
	if (zdev->dma_table) {
		spin_lock_irqsave(&s390_domain->list_lock, flags);
		list_del_rcu(&zdev->iommu_list);
		spin_unlock_irqrestore(&s390_domain->list_lock, flags);
	}

	zpci_unregister_ioat(zdev, 0);
	zdev->dma_table = NULL;
	zdev_s390_domain_update(zdev, domain);

	return 0;
}

static int s390_iommu_attach_device(struct iommu_domain *domain,
				    struct device *dev,
				    struct iommu_domain *old)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	struct zpci_dev *zdev = to_zpci_dev(dev);
	unsigned long flags;
	u8 status;
	int cc;

	if (!zdev)
		return -ENODEV;

	if (WARN_ON(domain->geometry.aperture_start > zdev->end_dma ||
		domain->geometry.aperture_end < zdev->start_dma))
		return -EINVAL;

	blocking_domain_attach_device(&blocking_domain, dev, old);

	/* If we fail now DMA remains blocked via blocking domain */
	cc = s390_iommu_domain_reg_ioat(zdev, domain, &status);
	if (reg_ioat_propagate_error(cc, status))
		return -EIO;
	zdev->dma_table = s390_domain->dma_table;
	zdev_s390_domain_update(zdev, domain);

	spin_lock_irqsave(&s390_domain->list_lock, flags);
	list_add_rcu(&zdev->iommu_list, &s390_domain->devices);
	spin_unlock_irqrestore(&s390_domain->list_lock, flags);

	return 0;
}

static void s390_iommu_get_resv_regions(struct device *dev,
					struct list_head *list)
{
	struct zpci_dev *zdev = to_zpci_dev(dev);
	struct iommu_resv_region *region;
	u64 max_size, end_resv;
	unsigned long flags;

	if (zdev->start_dma) {
		region = iommu_alloc_resv_region(0, zdev->start_dma, 0,
						 IOMMU_RESV_RESERVED, GFP_KERNEL);
		if (!region)
			return;
		list_add_tail(&region->list, list);
	}

	spin_lock_irqsave(&zdev->dom_lock, flags);
	if (zdev->s390_domain->type == IOMMU_DOMAIN_BLOCKED ||
	    zdev->s390_domain->type == IOMMU_DOMAIN_IDENTITY) {
		spin_unlock_irqrestore(&zdev->dom_lock, flags);
		return;
	}

	max_size = max_tbl_size(to_s390_domain(zdev->s390_domain));
	spin_unlock_irqrestore(&zdev->dom_lock, flags);

	if (zdev->end_dma < max_size) {
		end_resv = max_size - zdev->end_dma;
		region = iommu_alloc_resv_region(zdev->end_dma + 1, end_resv,
						 0, IOMMU_RESV_RESERVED,
						 GFP_KERNEL);
		if (!region)
			return;
		list_add_tail(&region->list, list);
	}
}

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

	if (!dev_is_pci(dev))
		return ERR_PTR(-ENODEV);

	zdev = to_zpci_dev(dev);

	if (zdev->start_dma > zdev->end_dma)
		return ERR_PTR(-EINVAL);

	if (zdev->tlb_refresh)
		dev->iommu->shadow_on_flush = 1;

	/* Start with DMA blocked */
	spin_lock_init(&zdev->dom_lock);
	zdev_s390_domain_update(zdev, &blocking_domain);

	return &zdev->iommu_dev;
}

static int zpci_refresh_all(struct zpci_dev *zdev)
{
	return zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
				  zdev->end_dma - zdev->start_dma + 1);
}

static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	struct zpci_dev *zdev;

	rcu_read_lock();
	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
		atomic64_inc(&s390_domain->ctrs.global_rpcits);
		zpci_refresh_all(zdev);
	}
	rcu_read_unlock();
}

static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
				  struct iommu_iotlb_gather *gather)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	size_t size = gather->end - gather->start + 1;
	struct zpci_dev *zdev;

	/* If gather was never added to there is nothing to flush */
	if (!gather->end)
		return;

	rcu_read_lock();
	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
		atomic64_inc(&s390_domain->ctrs.sync_rpcits);
		zpci_refresh_trans((u64)zdev->fh << 32, gather->start,
				   size);
	}
	rcu_read_unlock();
}

static int s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
				     unsigned long iova, size_t size)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	struct zpci_dev *zdev;
	int ret = 0;

	rcu_read_lock();
	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
		if (!zdev->tlb_refresh)
			continue;
		atomic64_inc(&s390_domain->ctrs.sync_map_rpcits);
		ret = zpci_refresh_trans((u64)zdev->fh << 32,
					 iova, size);
		/*
		 * let the hypervisor discover invalidated entries
		 * allowing it to free IOVAs and unpin pages
		 */
		if (ret == -ENOMEM) {
			ret = zpci_refresh_all(zdev);
			if (ret)
				break;
		}
	}
	rcu_read_unlock();

	return ret;
}

static int s390_iommu_validate_trans(struct s390_domain *s390_domain,
				     phys_addr_t pa, dma_addr_t dma_addr,
				     unsigned long nr_pages, int flags,
				     gfp_t gfp)
{
	phys_addr_t page_addr = pa & PAGE_MASK;
	unsigned long *entry;
	unsigned long i;
	int rc;

	for (i = 0; i < nr_pages; i++) {
		entry = dma_walk_cpu_trans(s390_domain, dma_addr, gfp);
		if (unlikely(!entry)) {
			rc = -ENOMEM;
			goto undo_cpu_trans;
		}
		dma_update_cpu_trans(entry, page_addr, flags);
		page_addr += PAGE_SIZE;
		dma_addr += PAGE_SIZE;
	}

	return 0;

undo_cpu_trans:
	while (i-- > 0) {
		dma_addr -= PAGE_SIZE;
		entry = dma_walk_cpu_trans(s390_domain, dma_addr, gfp);
		if (!entry)
			break;
		dma_update_cpu_trans(entry, 0, ZPCI_PTE_INVALID);
	}

	return rc;
}

static int s390_iommu_invalidate_trans(struct s390_domain *s390_domain,
				       dma_addr_t dma_addr, unsigned long nr_pages)
{
	unsigned long *entry;
	unsigned long i;
	int rc = 0;

	for (i = 0; i < nr_pages; i++) {
		entry = dma_walk_cpu_trans(s390_domain, dma_addr, GFP_ATOMIC);
		if (unlikely(!entry)) {
			rc = -EINVAL;
			break;
		}
		dma_update_cpu_trans(entry, 0, ZPCI_PTE_INVALID);
		dma_addr += PAGE_SIZE;
	}

	return rc;
}

static int s390_iommu_map_pages(struct iommu_domain *domain,
				unsigned long iova, phys_addr_t paddr,
				size_t pgsize, size_t pgcount,
				int prot, gfp_t gfp, size_t *mapped)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	size_t size = pgcount << __ffs(pgsize);
	int flags = ZPCI_PTE_VALID, rc = 0;

	if (pgsize != SZ_4K)
		return -EINVAL;

	if (iova < s390_domain->domain.geometry.aperture_start ||
	    (iova + size - 1) > s390_domain->domain.geometry.aperture_end)
		return -EINVAL;

	if (!IS_ALIGNED(iova | paddr, pgsize))
		return -EINVAL;

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

	rc = s390_iommu_validate_trans(s390_domain, paddr, iova,
				     pgcount, flags, gfp);
	if (!rc) {
		*mapped = size;
		atomic64_add(pgcount, &s390_domain->ctrs.mapped_pages);
	}

	return rc;
}

static unsigned long *get_rso_from_iova(struct s390_domain *domain,
					dma_addr_t iova)
{
	unsigned long *rfo;
	unsigned long rfe;
	unsigned int rfx;

	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RFX:
		rfo = domain->dma_table;
		rfx = calc_rfx(iova);
		rfe = READ_ONCE(rfo[rfx]);
		if (!reg_entry_isvalid(rfe))
			return NULL;
		return get_rf_rso(rfe);
	case ZPCI_TABLE_TYPE_RSX:
		return domain->dma_table;
	default:
		return NULL;
	}
}

static unsigned long *get_rto_from_iova(struct s390_domain *domain,
					dma_addr_t iova)
{
	unsigned long *rso;
	unsigned long rse;
	unsigned int rsx;

	switch (domain->origin_type) {
	case ZPCI_TABLE_TYPE_RFX:
	case ZPCI_TABLE_TYPE_RSX:
		rso = get_rso_from_iova(domain, iova);
		rsx = calc_rsx(iova);
		rse = READ_ONCE(rso[rsx]);
		if (!reg_entry_isvalid(rse))
			return NULL;
		return get_rs_rto(rse);
	case ZPCI_TABLE_TYPE_RTX:
		return domain->dma_table;
	default:
		return NULL;
	}
}

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 *rto, *sto, *pto;
	unsigned long ste, pte, rte;
	unsigned int rtx, sx, px;
	phys_addr_t phys = 0;

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

	rto = get_rto_from_iova(s390_domain, iova);
	if (!rto)
		return 0;

	rtx = calc_rtx(iova);
	sx = calc_sx(iova);
	px = calc_px(iova);

	rte = READ_ONCE(rto[rtx]);
	if (reg_entry_isvalid(rte)) {
		sto = get_rt_sto(rte);
		ste = READ_ONCE(sto[sx]);
		if (reg_entry_isvalid(ste)) {
			pto = get_st_pto(ste);
			pte = READ_ONCE(pto[px]);
			if (pt_entry_isvalid(pte))
				phys = pte & ZPCI_PTE_ADDR_MASK;
		}
	}

	return phys;
}

static size_t s390_iommu_unmap_pages(struct iommu_domain *domain,
				     unsigned long iova,
				     size_t pgsize, size_t pgcount,
				     struct iommu_iotlb_gather *gather)
{
	struct s390_domain *s390_domain = to_s390_domain(domain);
	size_t size = pgcount << __ffs(pgsize);
	int rc;

	if (WARN_ON(iova < s390_domain->domain.geometry.aperture_start ||
	    (iova + size - 1) > s390_domain->domain.geometry.aperture_end))
		return 0;

	rc = s390_iommu_invalidate_trans(s390_domain, iova, pgcount);
	if (rc)
		return 0;

	iommu_iotlb_gather_add_range(gather, iova, size);
	atomic64_add(pgcount, &s390_domain->ctrs.unmapped_pages);

	return size;
}

struct zpci_iommu_ctrs *zpci_get_iommu_ctrs(struct zpci_dev *zdev)
{
	struct s390_domain *s390_domain;

	lockdep_assert_held(&zdev->dom_lock);

	if (zdev->s390_domain->type == IOMMU_DOMAIN_BLOCKED ||
	    zdev->s390_domain->type == IOMMU_DOMAIN_IDENTITY)
		return NULL;

	s390_domain = to_s390_domain(zdev->s390_domain);
	return &s390_domain->ctrs;
}

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;

	if (zdev->rtr_avail) {
		rc = iommu_device_register(&zdev->iommu_dev,
					   &s390_iommu_rtr_ops, NULL);
	} else {
		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 int __init s390_iommu_setup(char *str)
{
	if (!strcmp(str, "strict")) {
		pr_warn("s390_iommu=strict deprecated; use iommu.strict=1 instead\n");
		iommu_set_dma_strict();
	}
	return 1;
}

__setup("s390_iommu=", s390_iommu_setup);

static int __init s390_iommu_aperture_setup(char *str)
{
	if (kstrtou32(str, 10, &s390_iommu_aperture_factor))
		s390_iommu_aperture_factor = 1;
	return 1;
}

__setup("s390_iommu_aperture=", s390_iommu_aperture_setup);

static int __init s390_iommu_init(void)
{
	int rc;

	iommu_dma_forcedac = true;
	s390_iommu_aperture = (u64)virt_to_phys(high_memory);
	if (!s390_iommu_aperture_factor)
		s390_iommu_aperture = ULONG_MAX;
	else
		s390_iommu_aperture *= s390_iommu_aperture_factor;

	rc = dma_alloc_cpu_table_caches();
	if (rc)
		return rc;

	return rc;
}
subsys_initcall(s390_iommu_init);

static int s390_attach_dev_identity(struct iommu_domain *domain,
				    struct device *dev,
				    struct iommu_domain *old)
{
	struct zpci_dev *zdev = to_zpci_dev(dev);
	u8 status;
	int cc;

	blocking_domain_attach_device(&blocking_domain, dev, old);

	/* If we fail now DMA remains blocked via blocking domain */
	cc = s390_iommu_domain_reg_ioat(zdev, domain, &status);
	if (reg_ioat_propagate_error(cc, status))
		return -EIO;

	zdev_s390_domain_update(zdev, domain);

	return 0;
}

static const struct iommu_domain_ops s390_identity_ops = {
	.attach_dev = s390_attach_dev_identity,
};

static struct iommu_domain s390_identity_domain = {
	.type = IOMMU_DOMAIN_IDENTITY,
	.ops = &s390_identity_ops,
};

static struct iommu_domain blocking_domain = {
	.type = IOMMU_DOMAIN_BLOCKED,
	.ops = &(const struct iommu_domain_ops) {
		.attach_dev	= blocking_domain_attach_device,
	}
};

#define S390_IOMMU_COMMON_OPS() \
	.blocked_domain		= &blocking_domain, \
	.release_domain		= &blocking_domain, \
	.capable = s390_iommu_capable, \
	.domain_alloc_paging = s390_domain_alloc_paging, \
	.probe_device = s390_iommu_probe_device, \
	.device_group = generic_device_group, \
	.get_resv_regions = s390_iommu_get_resv_regions, \
	.default_domain_ops = &(const struct iommu_domain_ops) { \
		.attach_dev	= s390_iommu_attach_device, \
		.map_pages	= s390_iommu_map_pages, \
		.unmap_pages	= s390_iommu_unmap_pages, \
		.flush_iotlb_all = s390_iommu_flush_iotlb_all, \
		.iotlb_sync      = s390_iommu_iotlb_sync, \
		.iotlb_sync_map  = s390_iommu_iotlb_sync_map, \
		.iova_to_phys	= s390_iommu_iova_to_phys, \
		.free		= s390_domain_free, \
	}

static const struct iommu_ops s390_iommu_ops = {
	S390_IOMMU_COMMON_OPS()
};

static const struct iommu_ops s390_iommu_rtr_ops = {
	.identity_domain	= &s390_identity_domain,
	S390_IOMMU_COMMON_OPS()
};