/*
* 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/pci.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)
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_pci_dev(dev)->sysdata;
struct s390_domain_device *domain_device;
unsigned long flags;
int rc;
if (!zdev)
return -ENODEV;
domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
if (!domain_device)
return -ENOMEM;
if (zdev->dma_table)
zpci_dma_exit_device(zdev);
zdev->dma_table = s390_domain->dma_table;
rc = zpci_register_ioat(zdev, 0, zdev->start_dma + PAGE_OFFSET,
zdev->start_dma + zdev->iommu_size - 1,
(u64) zdev->dma_table);
if (rc)
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);
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_pci_dev(dev)->sysdata;
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 int s390_iommu_add_device(struct device *dev)
{
struct iommu_group *group;
int rc;
group = iommu_group_get(dev);
if (!group) {
group = iommu_group_alloc();
if (IS_ERR(group))
return PTR_ERR(group);
}
rc = iommu_group_add_device(group, dev);
iommu_group_put(group);
return rc;
}
static void s390_iommu_remove_device(struct device *dev)
{
struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
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 remove_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);
}
iommu_group_remove_device(dev);
}
static int s390_iommu_update_trans(struct s390_domain *s390_domain,
unsigned long pa, dma_addr_t dma_addr,
size_t size, int flags)
{
struct s390_domain_device *domain_device;
u8 *page_addr = (u8 *) (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)
{
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, (unsigned long) 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 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, (unsigned long) paddr, iova,
size, flags);
if (rc)
return 0;
return size;
}
static 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,
.add_device = s390_iommu_add_device,
.remove_device = s390_iommu_remove_device,
.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);
