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8128f23c GS |
1 | /* |
2 | * IOMMU API for s390 PCI devices | |
3 | * | |
4 | * Copyright IBM Corp. 2015 | |
5 | * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com> | |
6 | */ | |
7 | ||
8 | #include <linux/pci.h> | |
9 | #include <linux/iommu.h> | |
10 | #include <linux/iommu-helper.h> | |
11 | #include <linux/pci.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 | struct s390_domain { | |
23 | struct iommu_domain domain; | |
24 | struct list_head devices; | |
25 | unsigned long *dma_table; | |
26 | spinlock_t dma_table_lock; | |
27 | spinlock_t list_lock; | |
28 | }; | |
29 | ||
30 | struct s390_domain_device { | |
31 | struct list_head list; | |
32 | struct zpci_dev *zdev; | |
33 | }; | |
34 | ||
35 | static struct s390_domain *to_s390_domain(struct iommu_domain *dom) | |
36 | { | |
37 | return container_of(dom, struct s390_domain, domain); | |
38 | } | |
39 | ||
40 | static bool s390_iommu_capable(enum iommu_cap cap) | |
41 | { | |
42 | switch (cap) { | |
43 | case IOMMU_CAP_CACHE_COHERENCY: | |
44 | return true; | |
45 | case IOMMU_CAP_INTR_REMAP: | |
46 | return true; | |
47 | default: | |
48 | return false; | |
49 | } | |
50 | } | |
51 | ||
52 | struct iommu_domain *s390_domain_alloc(unsigned domain_type) | |
53 | { | |
54 | struct s390_domain *s390_domain; | |
55 | ||
56 | if (domain_type != IOMMU_DOMAIN_UNMANAGED) | |
57 | return NULL; | |
58 | ||
59 | s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL); | |
60 | if (!s390_domain) | |
61 | return NULL; | |
62 | ||
63 | s390_domain->dma_table = dma_alloc_cpu_table(); | |
64 | if (!s390_domain->dma_table) { | |
65 | kfree(s390_domain); | |
66 | return NULL; | |
67 | } | |
68 | ||
69 | spin_lock_init(&s390_domain->dma_table_lock); | |
70 | spin_lock_init(&s390_domain->list_lock); | |
71 | INIT_LIST_HEAD(&s390_domain->devices); | |
72 | ||
73 | return &s390_domain->domain; | |
74 | } | |
75 | ||
76 | void s390_domain_free(struct iommu_domain *domain) | |
77 | { | |
78 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
79 | ||
80 | dma_cleanup_tables(s390_domain->dma_table); | |
81 | kfree(s390_domain); | |
82 | } | |
83 | ||
84 | static int s390_iommu_attach_device(struct iommu_domain *domain, | |
85 | struct device *dev) | |
86 | { | |
87 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
88 | struct zpci_dev *zdev = to_pci_dev(dev)->sysdata; | |
89 | struct s390_domain_device *domain_device; | |
90 | unsigned long flags; | |
91 | int rc; | |
92 | ||
93 | if (!zdev) | |
94 | return -ENODEV; | |
95 | ||
96 | domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL); | |
97 | if (!domain_device) | |
98 | return -ENOMEM; | |
99 | ||
100 | if (zdev->dma_table) | |
101 | zpci_dma_exit_device(zdev); | |
102 | ||
103 | zdev->dma_table = s390_domain->dma_table; | |
104 | rc = zpci_register_ioat(zdev, 0, zdev->start_dma + PAGE_OFFSET, | |
105 | zdev->start_dma + zdev->iommu_size - 1, | |
106 | (u64) zdev->dma_table); | |
107 | if (rc) | |
108 | goto out_restore; | |
109 | ||
110 | spin_lock_irqsave(&s390_domain->list_lock, flags); | |
111 | /* First device defines the DMA range limits */ | |
112 | if (list_empty(&s390_domain->devices)) { | |
113 | domain->geometry.aperture_start = zdev->start_dma; | |
114 | domain->geometry.aperture_end = zdev->end_dma; | |
115 | domain->geometry.force_aperture = true; | |
116 | /* Allow only devices with identical DMA range limits */ | |
117 | } else if (domain->geometry.aperture_start != zdev->start_dma || | |
118 | domain->geometry.aperture_end != zdev->end_dma) { | |
119 | rc = -EINVAL; | |
120 | spin_unlock_irqrestore(&s390_domain->list_lock, flags); | |
121 | goto out_restore; | |
122 | } | |
123 | domain_device->zdev = zdev; | |
124 | zdev->s390_domain = s390_domain; | |
125 | list_add(&domain_device->list, &s390_domain->devices); | |
126 | spin_unlock_irqrestore(&s390_domain->list_lock, flags); | |
127 | ||
128 | return 0; | |
129 | ||
130 | out_restore: | |
131 | zpci_dma_init_device(zdev); | |
132 | kfree(domain_device); | |
133 | ||
134 | return rc; | |
135 | } | |
136 | ||
137 | static void s390_iommu_detach_device(struct iommu_domain *domain, | |
138 | struct device *dev) | |
139 | { | |
140 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
141 | struct zpci_dev *zdev = to_pci_dev(dev)->sysdata; | |
142 | struct s390_domain_device *domain_device, *tmp; | |
143 | unsigned long flags; | |
144 | int found = 0; | |
145 | ||
146 | if (!zdev) | |
147 | return; | |
148 | ||
149 | spin_lock_irqsave(&s390_domain->list_lock, flags); | |
150 | list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices, | |
151 | list) { | |
152 | if (domain_device->zdev == zdev) { | |
153 | list_del(&domain_device->list); | |
154 | kfree(domain_device); | |
155 | found = 1; | |
156 | break; | |
157 | } | |
158 | } | |
159 | spin_unlock_irqrestore(&s390_domain->list_lock, flags); | |
160 | ||
161 | if (found) { | |
162 | zdev->s390_domain = NULL; | |
163 | zpci_unregister_ioat(zdev, 0); | |
164 | zpci_dma_init_device(zdev); | |
165 | } | |
166 | } | |
167 | ||
168 | static int s390_iommu_add_device(struct device *dev) | |
169 | { | |
170 | struct iommu_group *group; | |
171 | int rc; | |
172 | ||
173 | group = iommu_group_get(dev); | |
174 | if (!group) { | |
175 | group = iommu_group_alloc(); | |
176 | if (IS_ERR(group)) | |
177 | return PTR_ERR(group); | |
178 | } | |
179 | ||
180 | rc = iommu_group_add_device(group, dev); | |
181 | iommu_group_put(group); | |
182 | ||
183 | return rc; | |
184 | } | |
185 | ||
186 | static void s390_iommu_remove_device(struct device *dev) | |
187 | { | |
188 | struct zpci_dev *zdev = to_pci_dev(dev)->sysdata; | |
189 | struct iommu_domain *domain; | |
190 | ||
191 | /* | |
192 | * This is a workaround for a scenario where the IOMMU API common code | |
193 | * "forgets" to call the detach_dev callback: After binding a device | |
194 | * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers | |
195 | * the attach_dev), removing the device via | |
196 | * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev, | |
197 | * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE | |
198 | * notifier. | |
199 | * | |
200 | * So let's call detach_dev from here if it hasn't been called before. | |
201 | */ | |
202 | if (zdev && zdev->s390_domain) { | |
203 | domain = iommu_get_domain_for_dev(dev); | |
204 | if (domain) | |
205 | s390_iommu_detach_device(domain, dev); | |
206 | } | |
207 | ||
208 | iommu_group_remove_device(dev); | |
209 | } | |
210 | ||
211 | static int s390_iommu_update_trans(struct s390_domain *s390_domain, | |
212 | unsigned long pa, dma_addr_t dma_addr, | |
213 | size_t size, int flags) | |
214 | { | |
215 | struct s390_domain_device *domain_device; | |
216 | u8 *page_addr = (u8 *) (pa & PAGE_MASK); | |
217 | dma_addr_t start_dma_addr = dma_addr; | |
218 | unsigned long irq_flags, nr_pages, i; | |
66728eee | 219 | unsigned long *entry; |
8128f23c GS |
220 | int rc = 0; |
221 | ||
222 | if (dma_addr < s390_domain->domain.geometry.aperture_start || | |
223 | dma_addr + size > s390_domain->domain.geometry.aperture_end) | |
224 | return -EINVAL; | |
225 | ||
226 | nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; | |
227 | if (!nr_pages) | |
228 | return 0; | |
229 | ||
230 | spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags); | |
231 | for (i = 0; i < nr_pages; i++) { | |
66728eee SO |
232 | entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr); |
233 | if (!entry) { | |
234 | rc = -ENOMEM; | |
235 | goto undo_cpu_trans; | |
236 | } | |
237 | dma_update_cpu_trans(entry, page_addr, flags); | |
8128f23c GS |
238 | page_addr += PAGE_SIZE; |
239 | dma_addr += PAGE_SIZE; | |
240 | } | |
241 | ||
242 | spin_lock(&s390_domain->list_lock); | |
243 | list_for_each_entry(domain_device, &s390_domain->devices, list) { | |
244 | rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32, | |
245 | start_dma_addr, nr_pages * PAGE_SIZE); | |
246 | if (rc) | |
247 | break; | |
248 | } | |
249 | spin_unlock(&s390_domain->list_lock); | |
66728eee SO |
250 | |
251 | undo_cpu_trans: | |
252 | if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) { | |
253 | flags = ZPCI_PTE_INVALID; | |
254 | while (i-- > 0) { | |
255 | page_addr -= PAGE_SIZE; | |
256 | dma_addr -= PAGE_SIZE; | |
257 | entry = dma_walk_cpu_trans(s390_domain->dma_table, | |
258 | dma_addr); | |
259 | if (!entry) | |
260 | break; | |
261 | dma_update_cpu_trans(entry, page_addr, flags); | |
262 | } | |
263 | } | |
8128f23c GS |
264 | spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags); |
265 | ||
266 | return rc; | |
267 | } | |
268 | ||
269 | static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova, | |
270 | phys_addr_t paddr, size_t size, int prot) | |
271 | { | |
272 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
273 | int flags = ZPCI_PTE_VALID, rc = 0; | |
274 | ||
275 | if (!(prot & IOMMU_READ)) | |
276 | return -EINVAL; | |
277 | ||
278 | if (!(prot & IOMMU_WRITE)) | |
279 | flags |= ZPCI_TABLE_PROTECTED; | |
280 | ||
281 | rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova, | |
282 | size, flags); | |
283 | ||
284 | return rc; | |
285 | } | |
286 | ||
287 | static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain, | |
288 | dma_addr_t iova) | |
289 | { | |
290 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
291 | unsigned long *sto, *pto, *rto, flags; | |
292 | unsigned int rtx, sx, px; | |
293 | phys_addr_t phys = 0; | |
294 | ||
295 | if (iova < domain->geometry.aperture_start || | |
296 | iova > domain->geometry.aperture_end) | |
297 | return 0; | |
298 | ||
299 | rtx = calc_rtx(iova); | |
300 | sx = calc_sx(iova); | |
301 | px = calc_px(iova); | |
302 | rto = s390_domain->dma_table; | |
303 | ||
304 | spin_lock_irqsave(&s390_domain->dma_table_lock, flags); | |
305 | if (rto && reg_entry_isvalid(rto[rtx])) { | |
306 | sto = get_rt_sto(rto[rtx]); | |
307 | if (sto && reg_entry_isvalid(sto[sx])) { | |
308 | pto = get_st_pto(sto[sx]); | |
309 | if (pto && pt_entry_isvalid(pto[px])) | |
310 | phys = pto[px] & ZPCI_PTE_ADDR_MASK; | |
311 | } | |
312 | } | |
313 | spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags); | |
314 | ||
315 | return phys; | |
316 | } | |
317 | ||
318 | static size_t s390_iommu_unmap(struct iommu_domain *domain, | |
319 | unsigned long iova, size_t size) | |
320 | { | |
321 | struct s390_domain *s390_domain = to_s390_domain(domain); | |
322 | int flags = ZPCI_PTE_INVALID; | |
323 | phys_addr_t paddr; | |
324 | int rc; | |
325 | ||
326 | paddr = s390_iommu_iova_to_phys(domain, iova); | |
327 | if (!paddr) | |
328 | return 0; | |
329 | ||
330 | rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova, | |
331 | size, flags); | |
332 | if (rc) | |
333 | return 0; | |
334 | ||
335 | return size; | |
336 | } | |
337 | ||
338 | static struct iommu_ops s390_iommu_ops = { | |
339 | .capable = s390_iommu_capable, | |
340 | .domain_alloc = s390_domain_alloc, | |
341 | .domain_free = s390_domain_free, | |
342 | .attach_dev = s390_iommu_attach_device, | |
343 | .detach_dev = s390_iommu_detach_device, | |
344 | .map = s390_iommu_map, | |
345 | .unmap = s390_iommu_unmap, | |
346 | .iova_to_phys = s390_iommu_iova_to_phys, | |
347 | .add_device = s390_iommu_add_device, | |
348 | .remove_device = s390_iommu_remove_device, | |
349 | .pgsize_bitmap = S390_IOMMU_PGSIZES, | |
350 | }; | |
351 | ||
352 | static int __init s390_iommu_init(void) | |
353 | { | |
354 | return bus_set_iommu(&pci_bus_type, &s390_iommu_ops); | |
355 | } | |
356 | subsys_initcall(s390_iommu_init); |