GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / iommu / s390-iommu.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * IOMMU API for s390 PCI devices
4  *
5  * Copyright IBM Corp. 2015
6  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
7  */
8
9 #include <linux/pci.h>
10 #include <linux/iommu.h>
11 #include <linux/iommu-helper.h>
12 #include <linux/sizes.h>
13 #include <asm/pci_dma.h>
14
15 /*
16  * Physically contiguous memory regions can be mapped with 4 KiB alignment,
17  * we allow all page sizes that are an order of 4KiB (no special large page
18  * support so far).
19  */
20 #define S390_IOMMU_PGSIZES      (~0xFFFUL)
21
22 static const struct iommu_ops s390_iommu_ops;
23
24 struct s390_domain {
25         struct iommu_domain     domain;
26         struct list_head        devices;
27         unsigned long           *dma_table;
28         spinlock_t              dma_table_lock;
29         spinlock_t              list_lock;
30 };
31
32 struct s390_domain_device {
33         struct list_head        list;
34         struct zpci_dev         *zdev;
35 };
36
37 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
38 {
39         return container_of(dom, struct s390_domain, domain);
40 }
41
42 static bool s390_iommu_capable(enum iommu_cap cap)
43 {
44         switch (cap) {
45         case IOMMU_CAP_CACHE_COHERENCY:
46                 return true;
47         case IOMMU_CAP_INTR_REMAP:
48                 return true;
49         default:
50                 return false;
51         }
52 }
53
54 static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
55 {
56         struct s390_domain *s390_domain;
57
58         if (domain_type != IOMMU_DOMAIN_UNMANAGED)
59                 return NULL;
60
61         s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
62         if (!s390_domain)
63                 return NULL;
64
65         s390_domain->dma_table = dma_alloc_cpu_table();
66         if (!s390_domain->dma_table) {
67                 kfree(s390_domain);
68                 return NULL;
69         }
70
71         spin_lock_init(&s390_domain->dma_table_lock);
72         spin_lock_init(&s390_domain->list_lock);
73         INIT_LIST_HEAD(&s390_domain->devices);
74
75         return &s390_domain->domain;
76 }
77
78 static void s390_domain_free(struct iommu_domain *domain)
79 {
80         struct s390_domain *s390_domain = to_s390_domain(domain);
81
82         dma_cleanup_tables(s390_domain->dma_table);
83         kfree(s390_domain);
84 }
85
86 static int s390_iommu_attach_device(struct iommu_domain *domain,
87                                     struct device *dev)
88 {
89         struct s390_domain *s390_domain = to_s390_domain(domain);
90         struct zpci_dev *zdev = to_zpci_dev(dev);
91         struct s390_domain_device *domain_device;
92         unsigned long flags;
93         int cc, rc;
94
95         if (!zdev)
96                 return -ENODEV;
97
98         domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
99         if (!domain_device)
100                 return -ENOMEM;
101
102         if (zdev->dma_table && !zdev->s390_domain) {
103                 cc = zpci_dma_exit_device(zdev);
104                 if (cc) {
105                         rc = -EIO;
106                         goto out_free;
107                 }
108         }
109
110         if (zdev->s390_domain)
111                 zpci_unregister_ioat(zdev, 0);
112
113         zdev->dma_table = s390_domain->dma_table;
114         cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
115                                 virt_to_phys(zdev->dma_table));
116         if (cc) {
117                 rc = -EIO;
118                 goto out_restore;
119         }
120
121         spin_lock_irqsave(&s390_domain->list_lock, flags);
122         /* First device defines the DMA range limits */
123         if (list_empty(&s390_domain->devices)) {
124                 domain->geometry.aperture_start = zdev->start_dma;
125                 domain->geometry.aperture_end = zdev->end_dma;
126                 domain->geometry.force_aperture = true;
127         /* Allow only devices with identical DMA range limits */
128         } else if (domain->geometry.aperture_start != zdev->start_dma ||
129                    domain->geometry.aperture_end != zdev->end_dma) {
130                 rc = -EINVAL;
131                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
132                 goto out_restore;
133         }
134         domain_device->zdev = zdev;
135         zdev->s390_domain = s390_domain;
136         list_add(&domain_device->list, &s390_domain->devices);
137         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
138
139         return 0;
140
141 out_restore:
142         if (!zdev->s390_domain) {
143                 zpci_dma_init_device(zdev);
144         } else {
145                 zdev->dma_table = zdev->s390_domain->dma_table;
146                 zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
147                                    virt_to_phys(zdev->dma_table));
148         }
149 out_free:
150         kfree(domain_device);
151
152         return rc;
153 }
154
155 static void s390_iommu_detach_device(struct iommu_domain *domain,
156                                      struct device *dev)
157 {
158         struct s390_domain *s390_domain = to_s390_domain(domain);
159         struct zpci_dev *zdev = to_zpci_dev(dev);
160         struct s390_domain_device *domain_device, *tmp;
161         unsigned long flags;
162         int found = 0;
163
164         if (!zdev)
165                 return;
166
167         spin_lock_irqsave(&s390_domain->list_lock, flags);
168         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
169                                  list) {
170                 if (domain_device->zdev == zdev) {
171                         list_del(&domain_device->list);
172                         kfree(domain_device);
173                         found = 1;
174                         break;
175                 }
176         }
177         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
178
179         if (found && (zdev->s390_domain == s390_domain)) {
180                 zdev->s390_domain = NULL;
181                 zpci_unregister_ioat(zdev, 0);
182                 zpci_dma_init_device(zdev);
183         }
184 }
185
186 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
187 {
188         struct zpci_dev *zdev = to_zpci_dev(dev);
189
190         return &zdev->iommu_dev;
191 }
192
193 static void s390_iommu_release_device(struct device *dev)
194 {
195         struct zpci_dev *zdev = to_zpci_dev(dev);
196         struct iommu_domain *domain;
197
198         /*
199          * This is a workaround for a scenario where the IOMMU API common code
200          * "forgets" to call the detach_dev callback: After binding a device
201          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
202          * the attach_dev), removing the device via
203          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
204          * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
205          * notifier.
206          *
207          * So let's call detach_dev from here if it hasn't been called before.
208          */
209         if (zdev && zdev->s390_domain) {
210                 domain = iommu_get_domain_for_dev(dev);
211                 if (domain)
212                         s390_iommu_detach_device(domain, dev);
213         }
214 }
215
216 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
217                                    phys_addr_t pa, dma_addr_t dma_addr,
218                                    size_t size, int flags)
219 {
220         struct s390_domain_device *domain_device;
221         phys_addr_t page_addr = pa & PAGE_MASK;
222         dma_addr_t start_dma_addr = dma_addr;
223         unsigned long irq_flags, nr_pages, i;
224         unsigned long *entry;
225         int rc = 0;
226
227         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
228             dma_addr + size > s390_domain->domain.geometry.aperture_end)
229                 return -EINVAL;
230
231         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
232         if (!nr_pages)
233                 return 0;
234
235         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
236         for (i = 0; i < nr_pages; i++) {
237                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
238                 if (!entry) {
239                         rc = -ENOMEM;
240                         goto undo_cpu_trans;
241                 }
242                 dma_update_cpu_trans(entry, page_addr, flags);
243                 page_addr += PAGE_SIZE;
244                 dma_addr += PAGE_SIZE;
245         }
246
247         spin_lock(&s390_domain->list_lock);
248         list_for_each_entry(domain_device, &s390_domain->devices, list) {
249                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
250                                         start_dma_addr, nr_pages * PAGE_SIZE);
251                 if (rc)
252                         break;
253         }
254         spin_unlock(&s390_domain->list_lock);
255
256 undo_cpu_trans:
257         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
258                 flags = ZPCI_PTE_INVALID;
259                 while (i-- > 0) {
260                         page_addr -= PAGE_SIZE;
261                         dma_addr -= PAGE_SIZE;
262                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
263                                                    dma_addr);
264                         if (!entry)
265                                 break;
266                         dma_update_cpu_trans(entry, page_addr, flags);
267                 }
268         }
269         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
270
271         return rc;
272 }
273
274 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
275                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
276 {
277         struct s390_domain *s390_domain = to_s390_domain(domain);
278         int flags = ZPCI_PTE_VALID, rc = 0;
279
280         if (!(prot & IOMMU_READ))
281                 return -EINVAL;
282
283         if (!(prot & IOMMU_WRITE))
284                 flags |= ZPCI_TABLE_PROTECTED;
285
286         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
287                                      size, flags);
288
289         return rc;
290 }
291
292 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
293                                            dma_addr_t iova)
294 {
295         struct s390_domain *s390_domain = to_s390_domain(domain);
296         unsigned long *sto, *pto, *rto, flags;
297         unsigned int rtx, sx, px;
298         phys_addr_t phys = 0;
299
300         if (iova < domain->geometry.aperture_start ||
301             iova > domain->geometry.aperture_end)
302                 return 0;
303
304         rtx = calc_rtx(iova);
305         sx = calc_sx(iova);
306         px = calc_px(iova);
307         rto = s390_domain->dma_table;
308
309         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
310         if (rto && reg_entry_isvalid(rto[rtx])) {
311                 sto = get_rt_sto(rto[rtx]);
312                 if (sto && reg_entry_isvalid(sto[sx])) {
313                         pto = get_st_pto(sto[sx]);
314                         if (pto && pt_entry_isvalid(pto[px]))
315                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
316                 }
317         }
318         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
319
320         return phys;
321 }
322
323 static size_t s390_iommu_unmap(struct iommu_domain *domain,
324                                unsigned long iova, size_t size,
325                                struct iommu_iotlb_gather *gather)
326 {
327         struct s390_domain *s390_domain = to_s390_domain(domain);
328         int flags = ZPCI_PTE_INVALID;
329         phys_addr_t paddr;
330         int rc;
331
332         paddr = s390_iommu_iova_to_phys(domain, iova);
333         if (!paddr)
334                 return 0;
335
336         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
337                                      size, flags);
338         if (rc)
339                 return 0;
340
341         return size;
342 }
343
344 int zpci_init_iommu(struct zpci_dev *zdev)
345 {
346         int rc = 0;
347
348         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
349                                     "s390-iommu.%08x", zdev->fid);
350         if (rc)
351                 goto out_err;
352
353         rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
354         if (rc)
355                 goto out_sysfs;
356
357         return 0;
358
359 out_sysfs:
360         iommu_device_sysfs_remove(&zdev->iommu_dev);
361
362 out_err:
363         return rc;
364 }
365
366 void zpci_destroy_iommu(struct zpci_dev *zdev)
367 {
368         iommu_device_unregister(&zdev->iommu_dev);
369         iommu_device_sysfs_remove(&zdev->iommu_dev);
370 }
371
372 static const struct iommu_ops s390_iommu_ops = {
373         .capable = s390_iommu_capable,
374         .domain_alloc = s390_domain_alloc,
375         .probe_device = s390_iommu_probe_device,
376         .release_device = s390_iommu_release_device,
377         .device_group = generic_device_group,
378         .pgsize_bitmap = S390_IOMMU_PGSIZES,
379         .default_domain_ops = &(const struct iommu_domain_ops) {
380                 .attach_dev     = s390_iommu_attach_device,
381                 .detach_dev     = s390_iommu_detach_device,
382                 .map            = s390_iommu_map,
383                 .unmap          = s390_iommu_unmap,
384                 .iova_to_phys   = s390_iommu_iova_to_phys,
385                 .free           = s390_domain_free,
386         }
387 };
388
389 static int __init s390_iommu_init(void)
390 {
391         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
392 }
393 subsys_initcall(s390_iommu_init);