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Release 4.10 drivers/iommu/s390-iommu.c

Directory: drivers/iommu
/*
 * 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)


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); }

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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; } }

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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; }

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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); }

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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; }

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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); } }

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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; }

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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); }

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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; }

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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; }

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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; }

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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; }

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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); }

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subsys_initcall(s390_iommu_init);

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Directory: drivers/iommu
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