1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2023 Advanced Micro Devices, Inc. */
3
4 #include <linux/anon_inodes.h>
5 #include <linux/file.h>
6 #include <linux/fs.h>
7 #include <linux/highmem.h>
8 #include <linux/vfio.h>
9 #include <linux/vfio_pci_core.h>
10
11 #include "vfio_dev.h"
12 #include "cmds.h"
13
14 static struct pds_vfio_lm_file *
pds_vfio_get_lm_file(const struct file_operations * fops,int flags,u64 size)15 pds_vfio_get_lm_file(const struct file_operations *fops, int flags, u64 size)
16 {
17 struct pds_vfio_lm_file *lm_file = NULL;
18 unsigned long long npages;
19 struct page **pages;
20 void *page_mem;
21 const void *p;
22
23 if (!size)
24 return NULL;
25
26 /* Alloc file structure */
27 lm_file = kzalloc(sizeof(*lm_file), GFP_KERNEL);
28 if (!lm_file)
29 return NULL;
30
31 /* Create file */
32 lm_file->filep =
33 anon_inode_getfile("pds_vfio_lm", fops, lm_file, flags);
34 if (IS_ERR(lm_file->filep))
35 goto out_free_file;
36
37 stream_open(lm_file->filep->f_inode, lm_file->filep);
38 mutex_init(&lm_file->lock);
39
40 /* prevent file from being released before we are done with it */
41 get_file(lm_file->filep);
42
43 /* Allocate memory for file pages */
44 npages = DIV_ROUND_UP_ULL(size, PAGE_SIZE);
45 pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
46 if (!pages)
47 goto out_put_file;
48
49 page_mem = kvzalloc(ALIGN(size, PAGE_SIZE), GFP_KERNEL);
50 if (!page_mem)
51 goto out_free_pages_array;
52
53 p = page_mem - offset_in_page(page_mem);
54 for (unsigned long long i = 0; i < npages; i++) {
55 if (is_vmalloc_addr(p))
56 pages[i] = vmalloc_to_page(p);
57 else
58 pages[i] = kmap_to_page((void *)p);
59 if (!pages[i])
60 goto out_free_page_mem;
61
62 p += PAGE_SIZE;
63 }
64
65 /* Create scatterlist of file pages to use for DMA mapping later */
66 if (sg_alloc_table_from_pages(&lm_file->sg_table, pages, npages, 0,
67 size, GFP_KERNEL))
68 goto out_free_page_mem;
69
70 lm_file->size = size;
71 lm_file->pages = pages;
72 lm_file->npages = npages;
73 lm_file->page_mem = page_mem;
74 lm_file->alloc_size = npages * PAGE_SIZE;
75
76 return lm_file;
77
78 out_free_page_mem:
79 kvfree(page_mem);
80 out_free_pages_array:
81 kfree(pages);
82 out_put_file:
83 fput(lm_file->filep);
84 mutex_destroy(&lm_file->lock);
85 out_free_file:
86 kfree(lm_file);
87
88 return NULL;
89 }
90
pds_vfio_put_lm_file(struct pds_vfio_lm_file * lm_file)91 static void pds_vfio_put_lm_file(struct pds_vfio_lm_file *lm_file)
92 {
93 mutex_lock(&lm_file->lock);
94
95 lm_file->disabled = true;
96 lm_file->size = 0;
97 lm_file->alloc_size = 0;
98 lm_file->filep->f_pos = 0;
99
100 /* Free scatter list of file pages */
101 sg_free_table(&lm_file->sg_table);
102
103 kvfree(lm_file->page_mem);
104 lm_file->page_mem = NULL;
105 kfree(lm_file->pages);
106 lm_file->pages = NULL;
107
108 mutex_unlock(&lm_file->lock);
109
110 /* allow file to be released since we are done with it */
111 fput(lm_file->filep);
112 }
113
pds_vfio_put_save_file(struct pds_vfio_pci_device * pds_vfio)114 void pds_vfio_put_save_file(struct pds_vfio_pci_device *pds_vfio)
115 {
116 if (!pds_vfio->save_file)
117 return;
118
119 pds_vfio_put_lm_file(pds_vfio->save_file);
120 pds_vfio->save_file = NULL;
121 }
122
pds_vfio_put_restore_file(struct pds_vfio_pci_device * pds_vfio)123 void pds_vfio_put_restore_file(struct pds_vfio_pci_device *pds_vfio)
124 {
125 if (!pds_vfio->restore_file)
126 return;
127
128 pds_vfio_put_lm_file(pds_vfio->restore_file);
129 pds_vfio->restore_file = NULL;
130 }
131
pds_vfio_get_file_page(struct pds_vfio_lm_file * lm_file,unsigned long offset)132 static struct page *pds_vfio_get_file_page(struct pds_vfio_lm_file *lm_file,
133 unsigned long offset)
134 {
135 unsigned long cur_offset = 0;
136 struct scatterlist *sg;
137 unsigned int i;
138
139 /* All accesses are sequential */
140 if (offset < lm_file->last_offset || !lm_file->last_offset_sg) {
141 lm_file->last_offset = 0;
142 lm_file->last_offset_sg = lm_file->sg_table.sgl;
143 lm_file->sg_last_entry = 0;
144 }
145
146 cur_offset = lm_file->last_offset;
147
148 for_each_sg(lm_file->last_offset_sg, sg,
149 lm_file->sg_table.orig_nents - lm_file->sg_last_entry, i) {
150 if (offset < sg->length + cur_offset) {
151 lm_file->last_offset_sg = sg;
152 lm_file->sg_last_entry += i;
153 lm_file->last_offset = cur_offset;
154 return sg_page(sg) + (offset - cur_offset) / PAGE_SIZE;
155 }
156 cur_offset += sg->length;
157 }
158
159 return NULL;
160 }
161
pds_vfio_release_file(struct inode * inode,struct file * filp)162 static int pds_vfio_release_file(struct inode *inode, struct file *filp)
163 {
164 struct pds_vfio_lm_file *lm_file = filp->private_data;
165
166 mutex_lock(&lm_file->lock);
167 lm_file->filep->f_pos = 0;
168 lm_file->size = 0;
169 mutex_unlock(&lm_file->lock);
170 mutex_destroy(&lm_file->lock);
171 kfree(lm_file);
172
173 return 0;
174 }
175
pds_vfio_save_read(struct file * filp,char __user * buf,size_t len,loff_t * pos)176 static ssize_t pds_vfio_save_read(struct file *filp, char __user *buf,
177 size_t len, loff_t *pos)
178 {
179 struct pds_vfio_lm_file *lm_file = filp->private_data;
180 ssize_t done = 0;
181
182 if (pos)
183 return -ESPIPE;
184 pos = &filp->f_pos;
185
186 mutex_lock(&lm_file->lock);
187
188 if (lm_file->disabled) {
189 done = -ENODEV;
190 goto out_unlock;
191 }
192
193 if (*pos > lm_file->size) {
194 done = -EINVAL;
195 goto out_unlock;
196 }
197
198 len = min_t(size_t, lm_file->size - *pos, len);
199 while (len) {
200 size_t page_offset;
201 struct page *page;
202 size_t page_len;
203 u8 *from_buff;
204 int err;
205
206 page_offset = (*pos) % PAGE_SIZE;
207 page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
208 if (!page) {
209 if (done == 0)
210 done = -EINVAL;
211 goto out_unlock;
212 }
213
214 page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
215 from_buff = kmap_local_page(page);
216 err = copy_to_user(buf, from_buff + page_offset, page_len);
217 kunmap_local(from_buff);
218 if (err) {
219 done = -EFAULT;
220 goto out_unlock;
221 }
222 *pos += page_len;
223 len -= page_len;
224 done += page_len;
225 buf += page_len;
226 }
227
228 out_unlock:
229 mutex_unlock(&lm_file->lock);
230 return done;
231 }
232
233 static const struct file_operations pds_vfio_save_fops = {
234 .owner = THIS_MODULE,
235 .read = pds_vfio_save_read,
236 .release = pds_vfio_release_file,
237 };
238
pds_vfio_get_save_file(struct pds_vfio_pci_device * pds_vfio)239 static int pds_vfio_get_save_file(struct pds_vfio_pci_device *pds_vfio)
240 {
241 struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
242 struct pds_vfio_lm_file *lm_file;
243 u64 size;
244 int err;
245
246 /* Get live migration state size in this state */
247 err = pds_vfio_get_lm_state_size_cmd(pds_vfio, &size);
248 if (err) {
249 dev_err(dev, "failed to get save status: %pe\n", ERR_PTR(err));
250 return err;
251 }
252
253 dev_dbg(dev, "save status, size = %lld\n", size);
254
255 if (!size) {
256 dev_err(dev, "invalid state size\n");
257 return -EIO;
258 }
259
260 lm_file = pds_vfio_get_lm_file(&pds_vfio_save_fops, O_RDONLY, size);
261 if (!lm_file) {
262 dev_err(dev, "failed to create save file\n");
263 return -ENOENT;
264 }
265
266 dev_dbg(dev, "size = %lld, alloc_size = %lld, npages = %lld\n",
267 lm_file->size, lm_file->alloc_size, lm_file->npages);
268
269 pds_vfio->save_file = lm_file;
270
271 return 0;
272 }
273
pds_vfio_restore_write(struct file * filp,const char __user * buf,size_t len,loff_t * pos)274 static ssize_t pds_vfio_restore_write(struct file *filp, const char __user *buf,
275 size_t len, loff_t *pos)
276 {
277 struct pds_vfio_lm_file *lm_file = filp->private_data;
278 loff_t requested_length;
279 ssize_t done = 0;
280
281 if (pos)
282 return -ESPIPE;
283
284 pos = &filp->f_pos;
285
286 if (*pos < 0 ||
287 check_add_overflow((loff_t)len, *pos, &requested_length))
288 return -EINVAL;
289
290 mutex_lock(&lm_file->lock);
291
292 if (lm_file->disabled) {
293 done = -ENODEV;
294 goto out_unlock;
295 }
296
297 while (len) {
298 size_t page_offset;
299 struct page *page;
300 size_t page_len;
301 u8 *to_buff;
302 int err;
303
304 page_offset = (*pos) % PAGE_SIZE;
305 page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
306 if (!page) {
307 if (done == 0)
308 done = -EINVAL;
309 goto out_unlock;
310 }
311
312 page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
313 to_buff = kmap_local_page(page);
314 err = copy_from_user(to_buff + page_offset, buf, page_len);
315 kunmap_local(to_buff);
316 if (err) {
317 done = -EFAULT;
318 goto out_unlock;
319 }
320 *pos += page_len;
321 len -= page_len;
322 done += page_len;
323 buf += page_len;
324 lm_file->size += page_len;
325 }
326 out_unlock:
327 mutex_unlock(&lm_file->lock);
328 return done;
329 }
330
331 static const struct file_operations pds_vfio_restore_fops = {
332 .owner = THIS_MODULE,
333 .write = pds_vfio_restore_write,
334 .release = pds_vfio_release_file,
335 };
336
pds_vfio_get_restore_file(struct pds_vfio_pci_device * pds_vfio)337 static int pds_vfio_get_restore_file(struct pds_vfio_pci_device *pds_vfio)
338 {
339 struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
340 struct pds_vfio_lm_file *lm_file;
341 u64 size;
342
343 size = sizeof(union pds_lm_dev_state);
344 dev_dbg(dev, "restore status, size = %lld\n", size);
345
346 if (!size) {
347 dev_err(dev, "invalid state size");
348 return -EIO;
349 }
350
351 lm_file = pds_vfio_get_lm_file(&pds_vfio_restore_fops, O_WRONLY, size);
352 if (!lm_file) {
353 dev_err(dev, "failed to create restore file");
354 return -ENOENT;
355 }
356 pds_vfio->restore_file = lm_file;
357
358 return 0;
359 }
360
361 struct file *
pds_vfio_step_device_state_locked(struct pds_vfio_pci_device * pds_vfio,enum vfio_device_mig_state next)362 pds_vfio_step_device_state_locked(struct pds_vfio_pci_device *pds_vfio,
363 enum vfio_device_mig_state next)
364 {
365 enum vfio_device_mig_state cur = pds_vfio->state;
366 int err;
367
368 if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_STOP_COPY) {
369 err = pds_vfio_get_save_file(pds_vfio);
370 if (err)
371 return ERR_PTR(err);
372
373 err = pds_vfio_get_lm_state_cmd(pds_vfio);
374 if (err) {
375 pds_vfio_put_save_file(pds_vfio);
376 return ERR_PTR(err);
377 }
378
379 return pds_vfio->save_file->filep;
380 }
381
382 if (cur == VFIO_DEVICE_STATE_STOP_COPY && next == VFIO_DEVICE_STATE_STOP) {
383 pds_vfio_put_save_file(pds_vfio);
384 pds_vfio_dirty_disable(pds_vfio, true);
385 return NULL;
386 }
387
388 if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RESUMING) {
389 err = pds_vfio_get_restore_file(pds_vfio);
390 if (err)
391 return ERR_PTR(err);
392
393 return pds_vfio->restore_file->filep;
394 }
395
396 if (cur == VFIO_DEVICE_STATE_RESUMING && next == VFIO_DEVICE_STATE_STOP) {
397 err = pds_vfio_set_lm_state_cmd(pds_vfio);
398 if (err)
399 return ERR_PTR(err);
400
401 pds_vfio_put_restore_file(pds_vfio);
402 return NULL;
403 }
404
405 if (cur == VFIO_DEVICE_STATE_RUNNING && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
406 pds_vfio_send_host_vf_lm_status_cmd(pds_vfio,
407 PDS_LM_STA_IN_PROGRESS);
408 err = pds_vfio_suspend_device_cmd(pds_vfio,
409 PDS_LM_SUSPEND_RESUME_TYPE_P2P);
410 if (err)
411 return ERR_PTR(err);
412
413 return NULL;
414 }
415
416 if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_RUNNING) {
417 err = pds_vfio_resume_device_cmd(pds_vfio,
418 PDS_LM_SUSPEND_RESUME_TYPE_FULL);
419 if (err)
420 return ERR_PTR(err);
421
422 pds_vfio_send_host_vf_lm_status_cmd(pds_vfio, PDS_LM_STA_NONE);
423 return NULL;
424 }
425
426 if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
427 err = pds_vfio_resume_device_cmd(pds_vfio,
428 PDS_LM_SUSPEND_RESUME_TYPE_P2P);
429 if (err)
430 return ERR_PTR(err);
431
432 return NULL;
433 }
434
435 if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_STOP) {
436 err = pds_vfio_suspend_device_cmd(pds_vfio,
437 PDS_LM_SUSPEND_RESUME_TYPE_FULL);
438 if (err)
439 return ERR_PTR(err);
440 return NULL;
441 }
442
443 return ERR_PTR(-EINVAL);
444 }
445