GNU Linux-libre 5.10.219-gnu1
[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 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)
103                 zpci_dma_exit_device(zdev);
104
105         zdev->dma_table = s390_domain->dma_table;
106         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
107                                 (u64) zdev->dma_table);
108         if (rc)
109                 goto out_restore;
110
111         spin_lock_irqsave(&s390_domain->list_lock, flags);
112         /* First device defines the DMA range limits */
113         if (list_empty(&s390_domain->devices)) {
114                 domain->geometry.aperture_start = zdev->start_dma;
115                 domain->geometry.aperture_end = zdev->end_dma;
116                 domain->geometry.force_aperture = true;
117         /* Allow only devices with identical DMA range limits */
118         } else if (domain->geometry.aperture_start != zdev->start_dma ||
119                    domain->geometry.aperture_end != zdev->end_dma) {
120                 rc = -EINVAL;
121                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
122                 goto out_restore;
123         }
124         domain_device->zdev = zdev;
125         zdev->s390_domain = s390_domain;
126         list_add(&domain_device->list, &s390_domain->devices);
127         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
128
129         return 0;
130
131 out_restore:
132         zpci_dma_init_device(zdev);
133         kfree(domain_device);
134
135         return rc;
136 }
137
138 static void s390_iommu_detach_device(struct iommu_domain *domain,
139                                      struct device *dev)
140 {
141         struct s390_domain *s390_domain = to_s390_domain(domain);
142         struct zpci_dev *zdev = to_zpci_dev(dev);
143         struct s390_domain_device *domain_device, *tmp;
144         unsigned long flags;
145         int found = 0;
146
147         if (!zdev)
148                 return;
149
150         spin_lock_irqsave(&s390_domain->list_lock, flags);
151         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
152                                  list) {
153                 if (domain_device->zdev == zdev) {
154                         list_del(&domain_device->list);
155                         kfree(domain_device);
156                         found = 1;
157                         break;
158                 }
159         }
160         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
161
162         if (found) {
163                 zdev->s390_domain = NULL;
164                 zpci_unregister_ioat(zdev, 0);
165                 zpci_dma_init_device(zdev);
166         }
167 }
168
169 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
170 {
171         struct zpci_dev *zdev = to_zpci_dev(dev);
172
173         return &zdev->iommu_dev;
174 }
175
176 static void s390_iommu_release_device(struct device *dev)
177 {
178         struct zpci_dev *zdev = to_zpci_dev(dev);
179         struct iommu_domain *domain;
180
181         /*
182          * This is a workaround for a scenario where the IOMMU API common code
183          * "forgets" to call the detach_dev callback: After binding a device
184          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
185          * the attach_dev), removing the device via
186          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
187          * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
188          * notifier.
189          *
190          * So let's call detach_dev from here if it hasn't been called before.
191          */
192         if (zdev && zdev->s390_domain) {
193                 domain = iommu_get_domain_for_dev(dev);
194                 if (domain)
195                         s390_iommu_detach_device(domain, dev);
196         }
197 }
198
199 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
200                                    unsigned long pa, dma_addr_t dma_addr,
201                                    size_t size, int flags)
202 {
203         struct s390_domain_device *domain_device;
204         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
205         dma_addr_t start_dma_addr = dma_addr;
206         unsigned long irq_flags, nr_pages, i;
207         unsigned long *entry;
208         int rc = 0;
209
210         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
211             dma_addr + size > s390_domain->domain.geometry.aperture_end)
212                 return -EINVAL;
213
214         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
215         if (!nr_pages)
216                 return 0;
217
218         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
219         for (i = 0; i < nr_pages; i++) {
220                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
221                 if (!entry) {
222                         rc = -ENOMEM;
223                         goto undo_cpu_trans;
224                 }
225                 dma_update_cpu_trans(entry, page_addr, flags);
226                 page_addr += PAGE_SIZE;
227                 dma_addr += PAGE_SIZE;
228         }
229
230         spin_lock(&s390_domain->list_lock);
231         list_for_each_entry(domain_device, &s390_domain->devices, list) {
232                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
233                                         start_dma_addr, nr_pages * PAGE_SIZE);
234                 if (rc)
235                         break;
236         }
237         spin_unlock(&s390_domain->list_lock);
238
239 undo_cpu_trans:
240         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
241                 flags = ZPCI_PTE_INVALID;
242                 while (i-- > 0) {
243                         page_addr -= PAGE_SIZE;
244                         dma_addr -= PAGE_SIZE;
245                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
246                                                    dma_addr);
247                         if (!entry)
248                                 break;
249                         dma_update_cpu_trans(entry, page_addr, flags);
250                 }
251         }
252         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
253
254         return rc;
255 }
256
257 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
258                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
259 {
260         struct s390_domain *s390_domain = to_s390_domain(domain);
261         int flags = ZPCI_PTE_VALID, rc = 0;
262
263         if (!(prot & IOMMU_READ))
264                 return -EINVAL;
265
266         if (!(prot & IOMMU_WRITE))
267                 flags |= ZPCI_TABLE_PROTECTED;
268
269         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
270                                      size, flags);
271
272         return rc;
273 }
274
275 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
276                                            dma_addr_t iova)
277 {
278         struct s390_domain *s390_domain = to_s390_domain(domain);
279         unsigned long *sto, *pto, *rto, flags;
280         unsigned int rtx, sx, px;
281         phys_addr_t phys = 0;
282
283         if (iova < domain->geometry.aperture_start ||
284             iova > domain->geometry.aperture_end)
285                 return 0;
286
287         rtx = calc_rtx(iova);
288         sx = calc_sx(iova);
289         px = calc_px(iova);
290         rto = s390_domain->dma_table;
291
292         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
293         if (rto && reg_entry_isvalid(rto[rtx])) {
294                 sto = get_rt_sto(rto[rtx]);
295                 if (sto && reg_entry_isvalid(sto[sx])) {
296                         pto = get_st_pto(sto[sx]);
297                         if (pto && pt_entry_isvalid(pto[px]))
298                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
299                 }
300         }
301         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
302
303         return phys;
304 }
305
306 static size_t s390_iommu_unmap(struct iommu_domain *domain,
307                                unsigned long iova, size_t size,
308                                struct iommu_iotlb_gather *gather)
309 {
310         struct s390_domain *s390_domain = to_s390_domain(domain);
311         int flags = ZPCI_PTE_INVALID;
312         phys_addr_t paddr;
313         int rc;
314
315         paddr = s390_iommu_iova_to_phys(domain, iova);
316         if (!paddr)
317                 return 0;
318
319         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
320                                      size, flags);
321         if (rc)
322                 return 0;
323
324         return size;
325 }
326
327 int zpci_init_iommu(struct zpci_dev *zdev)
328 {
329         int rc = 0;
330
331         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
332                                     "s390-iommu.%08x", zdev->fid);
333         if (rc)
334                 goto out_err;
335
336         iommu_device_set_ops(&zdev->iommu_dev, &s390_iommu_ops);
337
338         rc = iommu_device_register(&zdev->iommu_dev);
339         if (rc)
340                 goto out_sysfs;
341
342         return 0;
343
344 out_sysfs:
345         iommu_device_sysfs_remove(&zdev->iommu_dev);
346
347 out_err:
348         return rc;
349 }
350
351 void zpci_destroy_iommu(struct zpci_dev *zdev)
352 {
353         iommu_device_unregister(&zdev->iommu_dev);
354         iommu_device_sysfs_remove(&zdev->iommu_dev);
355 }
356
357 static const struct iommu_ops s390_iommu_ops = {
358         .capable = s390_iommu_capable,
359         .domain_alloc = s390_domain_alloc,
360         .domain_free = s390_domain_free,
361         .attach_dev = s390_iommu_attach_device,
362         .detach_dev = s390_iommu_detach_device,
363         .map = s390_iommu_map,
364         .unmap = s390_iommu_unmap,
365         .iova_to_phys = s390_iommu_iova_to_phys,
366         .probe_device = s390_iommu_probe_device,
367         .release_device = s390_iommu_release_device,
368         .device_group = generic_device_group,
369         .pgsize_bitmap = S390_IOMMU_PGSIZES,
370 };
371
372 static int __init s390_iommu_init(void)
373 {
374         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
375 }
376 subsys_initcall(s390_iommu_init);