linux/drivers/iommu/s390-iommu.c
Niklas Schnelle 21c1f9021f s390/pci: use lock-free I/O translation updates
I/O translation tables on s390 use 8 byte page table entries and tables
which are allocated lazily but only freed when the entire I/O
translation table is torn down. Also each IOVA can at any time only
translate to one physical address Furthermore I/O table accesses by the
IOMMU hardware are cache coherent. With a bit of care we can thus use
atomic updates to manipulate the translation table without having to use
a global lock at all. This is done analogous to the existing I/O
translation table handling code used on Intel and AMD x86 systems.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20221109142903.4080275-6-schnelle@linux.ibm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
2022-11-19 10:28:18 +01:00

452 lines
11 KiB
C

// 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 <linux/rculist.h>
#include <linux/rcupdate.h>
#include <asm/pci_dma.h>
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 list_lock;
struct rcu_head rcu;
};
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)
{
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;
}
s390_domain->domain.geometry.force_aperture = true;
s390_domain->domain.geometry.aperture_start = 0;
s390_domain->domain.geometry.aperture_end = ZPCI_TABLE_SIZE_RT - 1;
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->dma_table);
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 __s390_iommu_detach_device(struct zpci_dev *zdev)
{
struct s390_domain *s390_domain = zdev->s390_domain;
unsigned long flags;
if (!s390_domain)
return;
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->s390_domain = NULL;
zdev->dma_table = NULL;
}
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);
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;
if (zdev->s390_domain)
__s390_iommu_detach_device(zdev);
else if (zdev->dma_table)
zpci_dma_exit_device(zdev);
cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
virt_to_phys(s390_domain->dma_table), &status);
/*
* If the device is undergoing error recovery the reset code
* will re-establish the new domain.
*/
if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
return -EIO;
zdev->dma_table = s390_domain->dma_table;
zdev->dma_table = s390_domain->dma_table;
zdev->s390_domain = s390_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_detach_device(struct iommu_domain *domain,
struct device *dev)
{
struct zpci_dev *zdev = to_zpci_dev(dev);
WARN_ON(zdev->s390_domain != to_s390_domain(domain));
__s390_iommu_detach_device(zdev);
zpci_dma_init_device(zdev);
}
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;
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);
}
if (zdev->end_dma < ZPCI_TABLE_SIZE_RT - 1) {
region = iommu_alloc_resv_region(zdev->end_dma + 1,
ZPCI_TABLE_SIZE_RT - zdev->end_dma - 1,
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 ||
zdev->start_dma > ZPCI_TABLE_SIZE_RT - 1)
return ERR_PTR(-EINVAL);
if (zdev->end_dma > ZPCI_TABLE_SIZE_RT - 1)
zdev->end_dma = ZPCI_TABLE_SIZE_RT - 1;
return &zdev->iommu_dev;
}
static void s390_iommu_release_device(struct device *dev)
{
struct zpci_dev *zdev = to_zpci_dev(dev);
/*
* release_device is expected to detach any domain currently attached
* to the device, but keep it attached to other devices in the group.
*/
if (zdev)
__s390_iommu_detach_device(zdev);
}
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) {
zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
zdev->end_dma - zdev->start_dma + 1);
}
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) {
zpci_refresh_trans((u64)zdev->fh << 32, gather->start,
size);
}
rcu_read_unlock();
}
static void 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;
rcu_read_lock();
list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
if (!zdev->tlb_refresh)
continue;
zpci_refresh_trans((u64)zdev->fh << 32,
iova, size);
}
rcu_read_unlock();
}
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)
{
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_table, dma_addr);
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_table,
dma_addr);
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_table, dma_addr);
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_READ))
return -EINVAL;
if (!(prot & IOMMU_WRITE))
flags |= ZPCI_TABLE_PROTECTED;
rc = s390_iommu_validate_trans(s390_domain, paddr, iova,
pgcount, flags);
if (!rc)
*mapped = size;
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 *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;
rtx = calc_rtx(iova);
sx = calc_sx(iova);
px = calc_px(iova);
rto = s390_domain->dma_table;
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);
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,
.probe_device = s390_iommu_probe_device,
.release_device = s390_iommu_release_device,
.device_group = generic_device_group,
.pgsize_bitmap = SZ_4K,
.get_resv_regions = s390_iommu_get_resv_regions,
.default_domain_ops = &(const struct iommu_domain_ops) {
.attach_dev = s390_iommu_attach_device,
.detach_dev = s390_iommu_detach_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,
}
};