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1 | /* |
2 | * VFIO: IOMMU DMA mapping support for TCE on POWER | |
3 | * | |
4 | * Copyright (C) 2013 IBM Corp. All rights reserved. | |
5 | * Author: Alexey Kardashevskiy <aik@ozlabs.ru> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * Derived from original vfio_iommu_type1.c: | |
12 | * Copyright (C) 2012 Red Hat, Inc. All rights reserved. | |
13 | * Author: Alex Williamson <alex.williamson@redhat.com> | |
14 | */ | |
15 | ||
16 | #include <linux/module.h> | |
17 | #include <linux/pci.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/uaccess.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/vfio.h> | |
22 | #include <asm/iommu.h> | |
23 | #include <asm/tce.h> | |
24 | ||
25 | #define DRIVER_VERSION "0.1" | |
26 | #define DRIVER_AUTHOR "aik@ozlabs.ru" | |
27 | #define DRIVER_DESC "VFIO IOMMU SPAPR TCE" | |
28 | ||
29 | static void tce_iommu_detach_group(void *iommu_data, | |
30 | struct iommu_group *iommu_group); | |
31 | ||
32 | /* | |
33 | * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation | |
34 | * | |
35 | * This code handles mapping and unmapping of user data buffers | |
36 | * into DMA'ble space using the IOMMU | |
37 | */ | |
38 | ||
39 | /* | |
40 | * The container descriptor supports only a single group per container. | |
41 | * Required by the API as the container is not supplied with the IOMMU group | |
42 | * at the moment of initialization. | |
43 | */ | |
44 | struct tce_container { | |
45 | struct mutex lock; | |
46 | struct iommu_table *tbl; | |
47 | bool enabled; | |
48 | }; | |
49 | ||
50 | static int tce_iommu_enable(struct tce_container *container) | |
51 | { | |
52 | int ret = 0; | |
53 | unsigned long locked, lock_limit, npages; | |
54 | struct iommu_table *tbl = container->tbl; | |
55 | ||
56 | if (!container->tbl) | |
57 | return -ENXIO; | |
58 | ||
59 | if (!current->mm) | |
60 | return -ESRCH; /* process exited */ | |
61 | ||
62 | if (container->enabled) | |
63 | return -EBUSY; | |
64 | ||
65 | /* | |
66 | * When userspace pages are mapped into the IOMMU, they are effectively | |
67 | * locked memory, so, theoretically, we need to update the accounting | |
68 | * of locked pages on each map and unmap. For powerpc, the map unmap | |
69 | * paths can be very hot, though, and the accounting would kill | |
70 | * performance, especially since it would be difficult to impossible | |
71 | * to handle the accounting in real mode only. | |
72 | * | |
73 | * To address that, rather than precisely accounting every page, we | |
74 | * instead account for a worst case on locked memory when the iommu is | |
75 | * enabled and disabled. The worst case upper bound on locked memory | |
76 | * is the size of the whole iommu window, which is usually relatively | |
77 | * small (compared to total memory sizes) on POWER hardware. | |
78 | * | |
79 | * Also we don't have a nice way to fail on H_PUT_TCE due to ulimits, | |
80 | * that would effectively kill the guest at random points, much better | |
81 | * enforcing the limit based on the max that the guest can map. | |
82 | */ | |
83 | down_write(¤t->mm->mmap_sem); | |
84 | npages = (tbl->it_size << IOMMU_PAGE_SHIFT) >> PAGE_SHIFT; | |
85 | locked = current->mm->locked_vm + npages; | |
86 | lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; | |
87 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) { | |
88 | pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n", | |
89 | rlimit(RLIMIT_MEMLOCK)); | |
90 | ret = -ENOMEM; | |
91 | } else { | |
92 | ||
93 | current->mm->locked_vm += npages; | |
94 | container->enabled = true; | |
95 | } | |
96 | up_write(¤t->mm->mmap_sem); | |
97 | ||
98 | return ret; | |
99 | } | |
100 | ||
101 | static void tce_iommu_disable(struct tce_container *container) | |
102 | { | |
103 | if (!container->enabled) | |
104 | return; | |
105 | ||
106 | container->enabled = false; | |
107 | ||
108 | if (!container->tbl || !current->mm) | |
109 | return; | |
110 | ||
111 | down_write(¤t->mm->mmap_sem); | |
112 | current->mm->locked_vm -= (container->tbl->it_size << | |
113 | IOMMU_PAGE_SHIFT) >> PAGE_SHIFT; | |
114 | up_write(¤t->mm->mmap_sem); | |
115 | } | |
116 | ||
117 | static void *tce_iommu_open(unsigned long arg) | |
118 | { | |
119 | struct tce_container *container; | |
120 | ||
121 | if (arg != VFIO_SPAPR_TCE_IOMMU) { | |
122 | pr_err("tce_vfio: Wrong IOMMU type\n"); | |
123 | return ERR_PTR(-EINVAL); | |
124 | } | |
125 | ||
126 | container = kzalloc(sizeof(*container), GFP_KERNEL); | |
127 | if (!container) | |
128 | return ERR_PTR(-ENOMEM); | |
129 | ||
130 | mutex_init(&container->lock); | |
131 | ||
132 | return container; | |
133 | } | |
134 | ||
135 | static void tce_iommu_release(void *iommu_data) | |
136 | { | |
137 | struct tce_container *container = iommu_data; | |
138 | ||
139 | WARN_ON(container->tbl && !container->tbl->it_group); | |
140 | tce_iommu_disable(container); | |
141 | ||
142 | if (container->tbl && container->tbl->it_group) | |
143 | tce_iommu_detach_group(iommu_data, container->tbl->it_group); | |
144 | ||
145 | mutex_destroy(&container->lock); | |
146 | ||
147 | kfree(container); | |
148 | } | |
149 | ||
150 | static long tce_iommu_ioctl(void *iommu_data, | |
151 | unsigned int cmd, unsigned long arg) | |
152 | { | |
153 | struct tce_container *container = iommu_data; | |
154 | unsigned long minsz; | |
155 | long ret; | |
156 | ||
157 | switch (cmd) { | |
158 | case VFIO_CHECK_EXTENSION: | |
159 | return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0; | |
160 | ||
161 | case VFIO_IOMMU_SPAPR_TCE_GET_INFO: { | |
162 | struct vfio_iommu_spapr_tce_info info; | |
163 | struct iommu_table *tbl = container->tbl; | |
164 | ||
165 | if (WARN_ON(!tbl)) | |
166 | return -ENXIO; | |
167 | ||
168 | minsz = offsetofend(struct vfio_iommu_spapr_tce_info, | |
169 | dma32_window_size); | |
170 | ||
171 | if (copy_from_user(&info, (void __user *)arg, minsz)) | |
172 | return -EFAULT; | |
173 | ||
174 | if (info.argsz < minsz) | |
175 | return -EINVAL; | |
176 | ||
177 | info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT; | |
178 | info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT; | |
179 | info.flags = 0; | |
180 | ||
181 | if (copy_to_user((void __user *)arg, &info, minsz)) | |
182 | return -EFAULT; | |
183 | ||
184 | return 0; | |
185 | } | |
186 | case VFIO_IOMMU_MAP_DMA: { | |
187 | struct vfio_iommu_type1_dma_map param; | |
188 | struct iommu_table *tbl = container->tbl; | |
189 | unsigned long tce, i; | |
190 | ||
191 | if (!tbl) | |
192 | return -ENXIO; | |
193 | ||
194 | BUG_ON(!tbl->it_group); | |
195 | ||
196 | minsz = offsetofend(struct vfio_iommu_type1_dma_map, size); | |
197 | ||
198 | if (copy_from_user(¶m, (void __user *)arg, minsz)) | |
199 | return -EFAULT; | |
200 | ||
201 | if (param.argsz < minsz) | |
202 | return -EINVAL; | |
203 | ||
204 | if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ | | |
205 | VFIO_DMA_MAP_FLAG_WRITE)) | |
206 | return -EINVAL; | |
207 | ||
208 | if ((param.size & ~IOMMU_PAGE_MASK) || | |
209 | (param.vaddr & ~IOMMU_PAGE_MASK)) | |
210 | return -EINVAL; | |
211 | ||
212 | /* iova is checked by the IOMMU API */ | |
213 | tce = param.vaddr; | |
214 | if (param.flags & VFIO_DMA_MAP_FLAG_READ) | |
215 | tce |= TCE_PCI_READ; | |
216 | if (param.flags & VFIO_DMA_MAP_FLAG_WRITE) | |
217 | tce |= TCE_PCI_WRITE; | |
218 | ||
219 | ret = iommu_tce_put_param_check(tbl, param.iova, tce); | |
220 | if (ret) | |
221 | return ret; | |
222 | ||
223 | for (i = 0; i < (param.size >> IOMMU_PAGE_SHIFT); ++i) { | |
224 | ret = iommu_put_tce_user_mode(tbl, | |
225 | (param.iova >> IOMMU_PAGE_SHIFT) + i, | |
226 | tce); | |
227 | if (ret) | |
228 | break; | |
229 | tce += IOMMU_PAGE_SIZE; | |
230 | } | |
231 | if (ret) | |
232 | iommu_clear_tces_and_put_pages(tbl, | |
233 | param.iova >> IOMMU_PAGE_SHIFT, i); | |
234 | ||
235 | iommu_flush_tce(tbl); | |
236 | ||
237 | return ret; | |
238 | } | |
239 | case VFIO_IOMMU_UNMAP_DMA: { | |
240 | struct vfio_iommu_type1_dma_unmap param; | |
241 | struct iommu_table *tbl = container->tbl; | |
242 | ||
243 | if (WARN_ON(!tbl)) | |
244 | return -ENXIO; | |
245 | ||
246 | minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, | |
247 | size); | |
248 | ||
249 | if (copy_from_user(¶m, (void __user *)arg, minsz)) | |
250 | return -EFAULT; | |
251 | ||
252 | if (param.argsz < minsz) | |
253 | return -EINVAL; | |
254 | ||
255 | /* No flag is supported now */ | |
256 | if (param.flags) | |
257 | return -EINVAL; | |
258 | ||
259 | if (param.size & ~IOMMU_PAGE_MASK) | |
260 | return -EINVAL; | |
261 | ||
262 | ret = iommu_tce_clear_param_check(tbl, param.iova, 0, | |
263 | param.size >> IOMMU_PAGE_SHIFT); | |
264 | if (ret) | |
265 | return ret; | |
266 | ||
267 | ret = iommu_clear_tces_and_put_pages(tbl, | |
268 | param.iova >> IOMMU_PAGE_SHIFT, | |
269 | param.size >> IOMMU_PAGE_SHIFT); | |
270 | iommu_flush_tce(tbl); | |
271 | ||
272 | return ret; | |
273 | } | |
274 | case VFIO_IOMMU_ENABLE: | |
275 | mutex_lock(&container->lock); | |
276 | ret = tce_iommu_enable(container); | |
277 | mutex_unlock(&container->lock); | |
278 | return ret; | |
279 | ||
280 | ||
281 | case VFIO_IOMMU_DISABLE: | |
282 | mutex_lock(&container->lock); | |
283 | tce_iommu_disable(container); | |
284 | mutex_unlock(&container->lock); | |
285 | return 0; | |
286 | } | |
287 | ||
288 | return -ENOTTY; | |
289 | } | |
290 | ||
291 | static int tce_iommu_attach_group(void *iommu_data, | |
292 | struct iommu_group *iommu_group) | |
293 | { | |
294 | int ret; | |
295 | struct tce_container *container = iommu_data; | |
296 | struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group); | |
297 | ||
298 | BUG_ON(!tbl); | |
299 | mutex_lock(&container->lock); | |
300 | ||
301 | /* pr_debug("tce_vfio: Attaching group #%u to iommu %p\n", | |
302 | iommu_group_id(iommu_group), iommu_group); */ | |
303 | if (container->tbl) { | |
304 | pr_warn("tce_vfio: Only one group per IOMMU container is allowed, existing id=%d, attaching id=%d\n", | |
305 | iommu_group_id(container->tbl->it_group), | |
306 | iommu_group_id(iommu_group)); | |
307 | ret = -EBUSY; | |
308 | } else if (container->enabled) { | |
309 | pr_err("tce_vfio: attaching group #%u to enabled container\n", | |
310 | iommu_group_id(iommu_group)); | |
311 | ret = -EBUSY; | |
312 | } else { | |
313 | ret = iommu_take_ownership(tbl); | |
314 | if (!ret) | |
315 | container->tbl = tbl; | |
316 | } | |
317 | ||
318 | mutex_unlock(&container->lock); | |
319 | ||
320 | return ret; | |
321 | } | |
322 | ||
323 | static void tce_iommu_detach_group(void *iommu_data, | |
324 | struct iommu_group *iommu_group) | |
325 | { | |
326 | struct tce_container *container = iommu_data; | |
327 | struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group); | |
328 | ||
329 | BUG_ON(!tbl); | |
330 | mutex_lock(&container->lock); | |
331 | if (tbl != container->tbl) { | |
332 | pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n", | |
333 | iommu_group_id(iommu_group), | |
334 | iommu_group_id(tbl->it_group)); | |
335 | } else { | |
336 | if (container->enabled) { | |
337 | pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n", | |
338 | iommu_group_id(tbl->it_group)); | |
339 | tce_iommu_disable(container); | |
340 | } | |
341 | ||
342 | /* pr_debug("tce_vfio: detaching group #%u from iommu %p\n", | |
343 | iommu_group_id(iommu_group), iommu_group); */ | |
344 | container->tbl = NULL; | |
345 | iommu_release_ownership(tbl); | |
346 | } | |
347 | mutex_unlock(&container->lock); | |
348 | } | |
349 | ||
350 | const struct vfio_iommu_driver_ops tce_iommu_driver_ops = { | |
351 | .name = "iommu-vfio-powerpc", | |
352 | .owner = THIS_MODULE, | |
353 | .open = tce_iommu_open, | |
354 | .release = tce_iommu_release, | |
355 | .ioctl = tce_iommu_ioctl, | |
356 | .attach_group = tce_iommu_attach_group, | |
357 | .detach_group = tce_iommu_detach_group, | |
358 | }; | |
359 | ||
360 | static int __init tce_iommu_init(void) | |
361 | { | |
362 | return vfio_register_iommu_driver(&tce_iommu_driver_ops); | |
363 | } | |
364 | ||
365 | static void __exit tce_iommu_cleanup(void) | |
366 | { | |
367 | vfio_unregister_iommu_driver(&tce_iommu_driver_ops); | |
368 | } | |
369 | ||
370 | module_init(tce_iommu_init); | |
371 | module_exit(tce_iommu_cleanup); | |
372 | ||
373 | MODULE_VERSION(DRIVER_VERSION); | |
374 | MODULE_LICENSE("GPL v2"); | |
375 | MODULE_AUTHOR(DRIVER_AUTHOR); | |
376 | MODULE_DESCRIPTION(DRIVER_DESC); | |
377 |