summaryrefslogtreecommitdiffstats
path: root/drivers/vfio/pci/pds/lm.c
blob: 79fe2e66bb498682e46435df5dbc996fe46899b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2023 Advanced Micro Devices, Inc. */

#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/vfio.h>
#include <linux/vfio_pci_core.h>

#include "vfio_dev.h"
#include "cmds.h"

static struct pds_vfio_lm_file *
pds_vfio_get_lm_file(const struct file_operations *fops, int flags, u64 size)
{
	struct pds_vfio_lm_file *lm_file = NULL;
	unsigned long long npages;
	struct page **pages;
	void *page_mem;
	const void *p;

	if (!size)
		return NULL;

	/* Alloc file structure */
	lm_file = kzalloc(sizeof(*lm_file), GFP_KERNEL);
	if (!lm_file)
		return NULL;

	/* Create file */
	lm_file->filep =
		anon_inode_getfile("pds_vfio_lm", fops, lm_file, flags);
	if (IS_ERR(lm_file->filep))
		goto out_free_file;

	stream_open(lm_file->filep->f_inode, lm_file->filep);
	mutex_init(&lm_file->lock);

	/* prevent file from being released before we are done with it */
	get_file(lm_file->filep);

	/* Allocate memory for file pages */
	npages = DIV_ROUND_UP_ULL(size, PAGE_SIZE);
	pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
	if (!pages)
		goto out_put_file;

	page_mem = kvzalloc(ALIGN(size, PAGE_SIZE), GFP_KERNEL);
	if (!page_mem)
		goto out_free_pages_array;

	p = page_mem - offset_in_page(page_mem);
	for (unsigned long long i = 0; i < npages; i++) {
		if (is_vmalloc_addr(p))
			pages[i] = vmalloc_to_page(p);
		else
			pages[i] = kmap_to_page((void *)p);
		if (!pages[i])
			goto out_free_page_mem;

		p += PAGE_SIZE;
	}

	/* Create scatterlist of file pages to use for DMA mapping later */
	if (sg_alloc_table_from_pages(&lm_file->sg_table, pages, npages, 0,
				      size, GFP_KERNEL))
		goto out_free_page_mem;

	lm_file->size = size;
	lm_file->pages = pages;
	lm_file->npages = npages;
	lm_file->page_mem = page_mem;
	lm_file->alloc_size = npages * PAGE_SIZE;

	return lm_file;

out_free_page_mem:
	kvfree(page_mem);
out_free_pages_array:
	kfree(pages);
out_put_file:
	fput(lm_file->filep);
	mutex_destroy(&lm_file->lock);
out_free_file:
	kfree(lm_file);

	return NULL;
}

static void pds_vfio_put_lm_file(struct pds_vfio_lm_file *lm_file)
{
	mutex_lock(&lm_file->lock);

	lm_file->size = 0;
	lm_file->alloc_size = 0;

	/* Free scatter list of file pages */
	sg_free_table(&lm_file->sg_table);

	kvfree(lm_file->page_mem);
	lm_file->page_mem = NULL;
	kfree(lm_file->pages);
	lm_file->pages = NULL;

	mutex_unlock(&lm_file->lock);

	/* allow file to be released since we are done with it */
	fput(lm_file->filep);
}

void pds_vfio_put_save_file(struct pds_vfio_pci_device *pds_vfio)
{
	if (!pds_vfio->save_file)
		return;

	pds_vfio_put_lm_file(pds_vfio->save_file);
	pds_vfio->save_file = NULL;
}

void pds_vfio_put_restore_file(struct pds_vfio_pci_device *pds_vfio)
{
	if (!pds_vfio->restore_file)
		return;

	pds_vfio_put_lm_file(pds_vfio->restore_file);
	pds_vfio->restore_file = NULL;
}

static struct page *pds_vfio_get_file_page(struct pds_vfio_lm_file *lm_file,
					   unsigned long offset)
{
	unsigned long cur_offset = 0;
	struct scatterlist *sg;
	unsigned int i;

	/* All accesses are sequential */
	if (offset < lm_file->last_offset || !lm_file->last_offset_sg) {
		lm_file->last_offset = 0;
		lm_file->last_offset_sg = lm_file->sg_table.sgl;
		lm_file->sg_last_entry = 0;
	}

	cur_offset = lm_file->last_offset;

	for_each_sg(lm_file->last_offset_sg, sg,
		    lm_file->sg_table.orig_nents - lm_file->sg_last_entry, i) {
		if (offset < sg->length + cur_offset) {
			lm_file->last_offset_sg = sg;
			lm_file->sg_last_entry += i;
			lm_file->last_offset = cur_offset;
			return nth_page(sg_page(sg),
					(offset - cur_offset) / PAGE_SIZE);
		}
		cur_offset += sg->length;
	}

	return NULL;
}

static int pds_vfio_release_file(struct inode *inode, struct file *filp)
{
	struct pds_vfio_lm_file *lm_file = filp->private_data;

	mutex_lock(&lm_file->lock);
	lm_file->filep->f_pos = 0;
	lm_file->size = 0;
	mutex_unlock(&lm_file->lock);
	mutex_destroy(&lm_file->lock);
	kfree(lm_file);

	return 0;
}

static ssize_t pds_vfio_save_read(struct file *filp, char __user *buf,
				  size_t len, loff_t *pos)
{
	struct pds_vfio_lm_file *lm_file = filp->private_data;
	ssize_t done = 0;

	if (pos)
		return -ESPIPE;
	pos = &filp->f_pos;

	mutex_lock(&lm_file->lock);
	if (*pos > lm_file->size) {
		done = -EINVAL;
		goto out_unlock;
	}

	len = min_t(size_t, lm_file->size - *pos, len);
	while (len) {
		size_t page_offset;
		struct page *page;
		size_t page_len;
		u8 *from_buff;
		int err;

		page_offset = (*pos) % PAGE_SIZE;
		page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
		if (!page) {
			if (done == 0)
				done = -EINVAL;
			goto out_unlock;
		}

		page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
		from_buff = kmap_local_page(page);
		err = copy_to_user(buf, from_buff + page_offset, page_len);
		kunmap_local(from_buff);
		if (err) {
			done = -EFAULT;
			goto out_unlock;
		}
		*pos += page_len;
		len -= page_len;
		done += page_len;
		buf += page_len;
	}

out_unlock:
	mutex_unlock(&lm_file->lock);
	return done;
}

static const struct file_operations pds_vfio_save_fops = {
	.owner = THIS_MODULE,
	.read = pds_vfio_save_read,
	.release = pds_vfio_release_file,
	.llseek = no_llseek,
};

static int pds_vfio_get_save_file(struct pds_vfio_pci_device *pds_vfio)
{
	struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
	struct pds_vfio_lm_file *lm_file;
	u64 size;
	int err;

	/* Get live migration state size in this state */
	err = pds_vfio_get_lm_state_size_cmd(pds_vfio, &size);
	if (err) {
		dev_err(dev, "failed to get save status: %pe\n", ERR_PTR(err));
		return err;
	}

	dev_dbg(dev, "save status, size = %lld\n", size);

	if (!size) {
		dev_err(dev, "invalid state size\n");
		return -EIO;
	}

	lm_file = pds_vfio_get_lm_file(&pds_vfio_save_fops, O_RDONLY, size);
	if (!lm_file) {
		dev_err(dev, "failed to create save file\n");
		return -ENOENT;
	}

	dev_dbg(dev, "size = %lld, alloc_size = %lld, npages = %lld\n",
		lm_file->size, lm_file->alloc_size, lm_file->npages);

	pds_vfio->save_file = lm_file;

	return 0;
}

static ssize_t pds_vfio_restore_write(struct file *filp, const char __user *buf,
				      size_t len, loff_t *pos)
{
	struct pds_vfio_lm_file *lm_file = filp->private_data;
	loff_t requested_length;
	ssize_t done = 0;

	if (pos)
		return -ESPIPE;

	pos = &filp->f_pos;

	if (*pos < 0 ||
	    check_add_overflow((loff_t)len, *pos, &requested_length))
		return -EINVAL;

	mutex_lock(&lm_file->lock);

	while (len) {
		size_t page_offset;
		struct page *page;
		size_t page_len;
		u8 *to_buff;
		int err;

		page_offset = (*pos) % PAGE_SIZE;
		page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
		if (!page) {
			if (done == 0)
				done = -EINVAL;
			goto out_unlock;
		}

		page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
		to_buff = kmap_local_page(page);
		err = copy_from_user(to_buff + page_offset, buf, page_len);
		kunmap_local(to_buff);
		if (err) {
			done = -EFAULT;
			goto out_unlock;
		}
		*pos += page_len;
		len -= page_len;
		done += page_len;
		buf += page_len;
		lm_file->size += page_len;
	}
out_unlock:
	mutex_unlock(&lm_file->lock);
	return done;
}

static const struct file_operations pds_vfio_restore_fops = {
	.owner = THIS_MODULE,
	.write = pds_vfio_restore_write,
	.release = pds_vfio_release_file,
	.llseek = no_llseek,
};

static int pds_vfio_get_restore_file(struct pds_vfio_pci_device *pds_vfio)
{
	struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
	struct pds_vfio_lm_file *lm_file;
	u64 size;

	size = sizeof(union pds_lm_dev_state);
	dev_dbg(dev, "restore status, size = %lld\n", size);

	if (!size) {
		dev_err(dev, "invalid state size");
		return -EIO;
	}

	lm_file = pds_vfio_get_lm_file(&pds_vfio_restore_fops, O_WRONLY, size);
	if (!lm_file) {
		dev_err(dev, "failed to create restore file");
		return -ENOENT;
	}
	pds_vfio->restore_file = lm_file;

	return 0;
}

struct file *
pds_vfio_step_device_state_locked(struct pds_vfio_pci_device *pds_vfio,
				  enum vfio_device_mig_state next)
{
	enum vfio_device_mig_state cur = pds_vfio->state;
	int err;

	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_STOP_COPY) {
		err = pds_vfio_get_save_file(pds_vfio);
		if (err)
			return ERR_PTR(err);

		err = pds_vfio_get_lm_state_cmd(pds_vfio);
		if (err) {
			pds_vfio_put_save_file(pds_vfio);
			return ERR_PTR(err);
		}

		return pds_vfio->save_file->filep;
	}

	if (cur == VFIO_DEVICE_STATE_STOP_COPY && next == VFIO_DEVICE_STATE_STOP) {
		pds_vfio_put_save_file(pds_vfio);
		pds_vfio_dirty_disable(pds_vfio, true);
		return NULL;
	}

	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RESUMING) {
		err = pds_vfio_get_restore_file(pds_vfio);
		if (err)
			return ERR_PTR(err);

		return pds_vfio->restore_file->filep;
	}

	if (cur == VFIO_DEVICE_STATE_RESUMING && next == VFIO_DEVICE_STATE_STOP) {
		err = pds_vfio_set_lm_state_cmd(pds_vfio);
		if (err)
			return ERR_PTR(err);

		pds_vfio_put_restore_file(pds_vfio);
		return NULL;
	}

	if (cur == VFIO_DEVICE_STATE_RUNNING && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
		pds_vfio_send_host_vf_lm_status_cmd(pds_vfio,
						    PDS_LM_STA_IN_PROGRESS);
		err = pds_vfio_suspend_device_cmd(pds_vfio,
						  PDS_LM_SUSPEND_RESUME_TYPE_P2P);
		if (err)
			return ERR_PTR(err);

		return NULL;
	}

	if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_RUNNING) {
		err = pds_vfio_resume_device_cmd(pds_vfio,
						 PDS_LM_SUSPEND_RESUME_TYPE_FULL);
		if (err)
			return ERR_PTR(err);

		pds_vfio_send_host_vf_lm_status_cmd(pds_vfio, PDS_LM_STA_NONE);
		return NULL;
	}

	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
		err = pds_vfio_resume_device_cmd(pds_vfio,
						 PDS_LM_SUSPEND_RESUME_TYPE_P2P);
		if (err)
			return ERR_PTR(err);

		return NULL;
	}

	if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_STOP) {
		err = pds_vfio_suspend_device_cmd(pds_vfio,
						  PDS_LM_SUSPEND_RESUME_TYPE_FULL);
		if (err)
			return ERR_PTR(err);
		return NULL;
	}

	return ERR_PTR(-EINVAL);
}