diff options
Diffstat (limited to 'drivers/iommu/s390-iommu.c')
| -rw-r--r-- | drivers/iommu/s390-iommu.c | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c new file mode 100644 index 000000000..22d4db302 --- /dev/null +++ b/drivers/iommu/s390-iommu.c @@ -0,0 +1,385 @@ +// 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_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, zdev->end_dma, + (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 = iommu_group_get_for_dev(dev); + struct zpci_dev *zdev = to_pci_dev(dev)->sysdata; + + if (IS_ERR(group)) + return PTR_ERR(group); + + iommu_group_put(group); + iommu_device_link(&zdev->iommu_dev, dev); + + return 0; +} + +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_device_unlink(&zdev->iommu_dev, 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; +} + +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; + + iommu_device_set_ops(&zdev->iommu_dev, &s390_iommu_ops); + + rc = iommu_device_register(&zdev->iommu_dev); + 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, + .add_device = s390_iommu_add_device, + .remove_device = s390_iommu_remove_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); |