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Merge tag 'for-linus-20170825' of git://git.infradead.org/linux-mtd
[mirror_ubuntu-artful-kernel.git] / drivers / vfio / pci / vfio_pci_config.c
1 /*
2 * VFIO PCI config space virtualization
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
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:
12 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
13 * Author: Tom Lyon, pugs@cisco.com
14 */
15
16 /*
17 * This code handles reading and writing of PCI configuration registers.
18 * This is hairy because we want to allow a lot of flexibility to the
19 * user driver, but cannot trust it with all of the config fields.
20 * Tables determine which fields can be read and written, as well as
21 * which fields are 'virtualized' - special actions and translations to
22 * make it appear to the user that he has control, when in fact things
23 * must be negotiated with the underlying OS.
24 */
25
26 #include <linux/fs.h>
27 #include <linux/pci.h>
28 #include <linux/uaccess.h>
29 #include <linux/vfio.h>
30 #include <linux/slab.h>
31
32 #include "vfio_pci_private.h"
33
34 /* Fake capability ID for standard config space */
35 #define PCI_CAP_ID_BASIC 0
36
37 #define is_bar(offset) \
38 ((offset >= PCI_BASE_ADDRESS_0 && offset < PCI_BASE_ADDRESS_5 + 4) || \
39 (offset >= PCI_ROM_ADDRESS && offset < PCI_ROM_ADDRESS + 4))
40
41 /*
42 * Lengths of PCI Config Capabilities
43 * 0: Removed from the user visible capability list
44 * FF: Variable length
45 */
46 static const u8 pci_cap_length[PCI_CAP_ID_MAX + 1] = {
47 [PCI_CAP_ID_BASIC] = PCI_STD_HEADER_SIZEOF, /* pci config header */
48 [PCI_CAP_ID_PM] = PCI_PM_SIZEOF,
49 [PCI_CAP_ID_AGP] = PCI_AGP_SIZEOF,
50 [PCI_CAP_ID_VPD] = PCI_CAP_VPD_SIZEOF,
51 [PCI_CAP_ID_SLOTID] = 0, /* bridge - don't care */
52 [PCI_CAP_ID_MSI] = 0xFF, /* 10, 14, 20, or 24 */
53 [PCI_CAP_ID_CHSWP] = 0, /* cpci - not yet */
54 [PCI_CAP_ID_PCIX] = 0xFF, /* 8 or 24 */
55 [PCI_CAP_ID_HT] = 0xFF, /* hypertransport */
56 [PCI_CAP_ID_VNDR] = 0xFF, /* variable */
57 [PCI_CAP_ID_DBG] = 0, /* debug - don't care */
58 [PCI_CAP_ID_CCRC] = 0, /* cpci - not yet */
59 [PCI_CAP_ID_SHPC] = 0, /* hotswap - not yet */
60 [PCI_CAP_ID_SSVID] = 0, /* bridge - don't care */
61 [PCI_CAP_ID_AGP3] = 0, /* AGP8x - not yet */
62 [PCI_CAP_ID_SECDEV] = 0, /* secure device not yet */
63 [PCI_CAP_ID_EXP] = 0xFF, /* 20 or 44 */
64 [PCI_CAP_ID_MSIX] = PCI_CAP_MSIX_SIZEOF,
65 [PCI_CAP_ID_SATA] = 0xFF,
66 [PCI_CAP_ID_AF] = PCI_CAP_AF_SIZEOF,
67 };
68
69 /*
70 * Lengths of PCIe/PCI-X Extended Config Capabilities
71 * 0: Removed or masked from the user visible capability list
72 * FF: Variable length
73 */
74 static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = {
75 [PCI_EXT_CAP_ID_ERR] = PCI_ERR_ROOT_COMMAND,
76 [PCI_EXT_CAP_ID_VC] = 0xFF,
77 [PCI_EXT_CAP_ID_DSN] = PCI_EXT_CAP_DSN_SIZEOF,
78 [PCI_EXT_CAP_ID_PWR] = PCI_EXT_CAP_PWR_SIZEOF,
79 [PCI_EXT_CAP_ID_RCLD] = 0, /* root only - don't care */
80 [PCI_EXT_CAP_ID_RCILC] = 0, /* root only - don't care */
81 [PCI_EXT_CAP_ID_RCEC] = 0, /* root only - don't care */
82 [PCI_EXT_CAP_ID_MFVC] = 0xFF,
83 [PCI_EXT_CAP_ID_VC9] = 0xFF, /* same as CAP_ID_VC */
84 [PCI_EXT_CAP_ID_RCRB] = 0, /* root only - don't care */
85 [PCI_EXT_CAP_ID_VNDR] = 0xFF,
86 [PCI_EXT_CAP_ID_CAC] = 0, /* obsolete */
87 [PCI_EXT_CAP_ID_ACS] = 0xFF,
88 [PCI_EXT_CAP_ID_ARI] = PCI_EXT_CAP_ARI_SIZEOF,
89 [PCI_EXT_CAP_ID_ATS] = PCI_EXT_CAP_ATS_SIZEOF,
90 [PCI_EXT_CAP_ID_SRIOV] = PCI_EXT_CAP_SRIOV_SIZEOF,
91 [PCI_EXT_CAP_ID_MRIOV] = 0, /* not yet */
92 [PCI_EXT_CAP_ID_MCAST] = PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF,
93 [PCI_EXT_CAP_ID_PRI] = PCI_EXT_CAP_PRI_SIZEOF,
94 [PCI_EXT_CAP_ID_AMD_XXX] = 0, /* not yet */
95 [PCI_EXT_CAP_ID_REBAR] = 0xFF,
96 [PCI_EXT_CAP_ID_DPA] = 0xFF,
97 [PCI_EXT_CAP_ID_TPH] = 0xFF,
98 [PCI_EXT_CAP_ID_LTR] = PCI_EXT_CAP_LTR_SIZEOF,
99 [PCI_EXT_CAP_ID_SECPCI] = 0, /* not yet */
100 [PCI_EXT_CAP_ID_PMUX] = 0, /* not yet */
101 [PCI_EXT_CAP_ID_PASID] = 0, /* not yet */
102 };
103
104 /*
105 * Read/Write Permission Bits - one bit for each bit in capability
106 * Any field can be read if it exists, but what is read depends on
107 * whether the field is 'virtualized', or just pass thru to the
108 * hardware. Any virtualized field is also virtualized for writes.
109 * Writes are only permitted if they have a 1 bit here.
110 */
111 struct perm_bits {
112 u8 *virt; /* read/write virtual data, not hw */
113 u8 *write; /* writeable bits */
114 int (*readfn)(struct vfio_pci_device *vdev, int pos, int count,
115 struct perm_bits *perm, int offset, __le32 *val);
116 int (*writefn)(struct vfio_pci_device *vdev, int pos, int count,
117 struct perm_bits *perm, int offset, __le32 val);
118 };
119
120 #define NO_VIRT 0
121 #define ALL_VIRT 0xFFFFFFFFU
122 #define NO_WRITE 0
123 #define ALL_WRITE 0xFFFFFFFFU
124
125 static int vfio_user_config_read(struct pci_dev *pdev, int offset,
126 __le32 *val, int count)
127 {
128 int ret = -EINVAL;
129 u32 tmp_val = 0;
130
131 switch (count) {
132 case 1:
133 {
134 u8 tmp;
135 ret = pci_user_read_config_byte(pdev, offset, &tmp);
136 tmp_val = tmp;
137 break;
138 }
139 case 2:
140 {
141 u16 tmp;
142 ret = pci_user_read_config_word(pdev, offset, &tmp);
143 tmp_val = tmp;
144 break;
145 }
146 case 4:
147 ret = pci_user_read_config_dword(pdev, offset, &tmp_val);
148 break;
149 }
150
151 *val = cpu_to_le32(tmp_val);
152
153 return ret;
154 }
155
156 static int vfio_user_config_write(struct pci_dev *pdev, int offset,
157 __le32 val, int count)
158 {
159 int ret = -EINVAL;
160 u32 tmp_val = le32_to_cpu(val);
161
162 switch (count) {
163 case 1:
164 ret = pci_user_write_config_byte(pdev, offset, tmp_val);
165 break;
166 case 2:
167 ret = pci_user_write_config_word(pdev, offset, tmp_val);
168 break;
169 case 4:
170 ret = pci_user_write_config_dword(pdev, offset, tmp_val);
171 break;
172 }
173
174 return ret;
175 }
176
177 static int vfio_default_config_read(struct vfio_pci_device *vdev, int pos,
178 int count, struct perm_bits *perm,
179 int offset, __le32 *val)
180 {
181 __le32 virt = 0;
182
183 memcpy(val, vdev->vconfig + pos, count);
184
185 memcpy(&virt, perm->virt + offset, count);
186
187 /* Any non-virtualized bits? */
188 if (cpu_to_le32(~0U >> (32 - (count * 8))) != virt) {
189 struct pci_dev *pdev = vdev->pdev;
190 __le32 phys_val = 0;
191 int ret;
192
193 ret = vfio_user_config_read(pdev, pos, &phys_val, count);
194 if (ret)
195 return ret;
196
197 *val = (phys_val & ~virt) | (*val & virt);
198 }
199
200 return count;
201 }
202
203 static int vfio_default_config_write(struct vfio_pci_device *vdev, int pos,
204 int count, struct perm_bits *perm,
205 int offset, __le32 val)
206 {
207 __le32 virt = 0, write = 0;
208
209 memcpy(&write, perm->write + offset, count);
210
211 if (!write)
212 return count; /* drop, no writable bits */
213
214 memcpy(&virt, perm->virt + offset, count);
215
216 /* Virtualized and writable bits go to vconfig */
217 if (write & virt) {
218 __le32 virt_val = 0;
219
220 memcpy(&virt_val, vdev->vconfig + pos, count);
221
222 virt_val &= ~(write & virt);
223 virt_val |= (val & (write & virt));
224
225 memcpy(vdev->vconfig + pos, &virt_val, count);
226 }
227
228 /* Non-virtualzed and writable bits go to hardware */
229 if (write & ~virt) {
230 struct pci_dev *pdev = vdev->pdev;
231 __le32 phys_val = 0;
232 int ret;
233
234 ret = vfio_user_config_read(pdev, pos, &phys_val, count);
235 if (ret)
236 return ret;
237
238 phys_val &= ~(write & ~virt);
239 phys_val |= (val & (write & ~virt));
240
241 ret = vfio_user_config_write(pdev, pos, phys_val, count);
242 if (ret)
243 return ret;
244 }
245
246 return count;
247 }
248
249 /* Allow direct read from hardware, except for capability next pointer */
250 static int vfio_direct_config_read(struct vfio_pci_device *vdev, int pos,
251 int count, struct perm_bits *perm,
252 int offset, __le32 *val)
253 {
254 int ret;
255
256 ret = vfio_user_config_read(vdev->pdev, pos, val, count);
257 if (ret)
258 return ret;
259
260 if (pos >= PCI_CFG_SPACE_SIZE) { /* Extended cap header mangling */
261 if (offset < 4)
262 memcpy(val, vdev->vconfig + pos, count);
263 } else if (pos >= PCI_STD_HEADER_SIZEOF) { /* Std cap mangling */
264 if (offset == PCI_CAP_LIST_ID && count > 1)
265 memcpy(val, vdev->vconfig + pos,
266 min(PCI_CAP_FLAGS, count));
267 else if (offset == PCI_CAP_LIST_NEXT)
268 memcpy(val, vdev->vconfig + pos, 1);
269 }
270
271 return count;
272 }
273
274 /* Raw access skips any kind of virtualization */
275 static int vfio_raw_config_write(struct vfio_pci_device *vdev, int pos,
276 int count, struct perm_bits *perm,
277 int offset, __le32 val)
278 {
279 int ret;
280
281 ret = vfio_user_config_write(vdev->pdev, pos, val, count);
282 if (ret)
283 return ret;
284
285 return count;
286 }
287
288 static int vfio_raw_config_read(struct vfio_pci_device *vdev, int pos,
289 int count, struct perm_bits *perm,
290 int offset, __le32 *val)
291 {
292 int ret;
293
294 ret = vfio_user_config_read(vdev->pdev, pos, val, count);
295 if (ret)
296 return ret;
297
298 return count;
299 }
300
301 /* Virt access uses only virtualization */
302 static int vfio_virt_config_write(struct vfio_pci_device *vdev, int pos,
303 int count, struct perm_bits *perm,
304 int offset, __le32 val)
305 {
306 memcpy(vdev->vconfig + pos, &val, count);
307 return count;
308 }
309
310 static int vfio_virt_config_read(struct vfio_pci_device *vdev, int pos,
311 int count, struct perm_bits *perm,
312 int offset, __le32 *val)
313 {
314 memcpy(val, vdev->vconfig + pos, count);
315 return count;
316 }
317
318 /* Default capability regions to read-only, no-virtualization */
319 static struct perm_bits cap_perms[PCI_CAP_ID_MAX + 1] = {
320 [0 ... PCI_CAP_ID_MAX] = { .readfn = vfio_direct_config_read }
321 };
322 static struct perm_bits ecap_perms[PCI_EXT_CAP_ID_MAX + 1] = {
323 [0 ... PCI_EXT_CAP_ID_MAX] = { .readfn = vfio_direct_config_read }
324 };
325 /*
326 * Default unassigned regions to raw read-write access. Some devices
327 * require this to function as they hide registers between the gaps in
328 * config space (be2net). Like MMIO and I/O port registers, we have
329 * to trust the hardware isolation.
330 */
331 static struct perm_bits unassigned_perms = {
332 .readfn = vfio_raw_config_read,
333 .writefn = vfio_raw_config_write
334 };
335
336 static struct perm_bits virt_perms = {
337 .readfn = vfio_virt_config_read,
338 .writefn = vfio_virt_config_write
339 };
340
341 static void free_perm_bits(struct perm_bits *perm)
342 {
343 kfree(perm->virt);
344 kfree(perm->write);
345 perm->virt = NULL;
346 perm->write = NULL;
347 }
348
349 static int alloc_perm_bits(struct perm_bits *perm, int size)
350 {
351 /*
352 * Round up all permission bits to the next dword, this lets us
353 * ignore whether a read/write exceeds the defined capability
354 * structure. We can do this because:
355 * - Standard config space is already dword aligned
356 * - Capabilities are all dword aligned (bits 0:1 of next reserved)
357 * - Express capabilities defined as dword aligned
358 */
359 size = round_up(size, 4);
360
361 /*
362 * Zero state is
363 * - All Readable, None Writeable, None Virtualized
364 */
365 perm->virt = kzalloc(size, GFP_KERNEL);
366 perm->write = kzalloc(size, GFP_KERNEL);
367 if (!perm->virt || !perm->write) {
368 free_perm_bits(perm);
369 return -ENOMEM;
370 }
371
372 perm->readfn = vfio_default_config_read;
373 perm->writefn = vfio_default_config_write;
374
375 return 0;
376 }
377
378 /*
379 * Helper functions for filling in permission tables
380 */
381 static inline void p_setb(struct perm_bits *p, int off, u8 virt, u8 write)
382 {
383 p->virt[off] = virt;
384 p->write[off] = write;
385 }
386
387 /* Handle endian-ness - pci and tables are little-endian */
388 static inline void p_setw(struct perm_bits *p, int off, u16 virt, u16 write)
389 {
390 *(__le16 *)(&p->virt[off]) = cpu_to_le16(virt);
391 *(__le16 *)(&p->write[off]) = cpu_to_le16(write);
392 }
393
394 /* Handle endian-ness - pci and tables are little-endian */
395 static inline void p_setd(struct perm_bits *p, int off, u32 virt, u32 write)
396 {
397 *(__le32 *)(&p->virt[off]) = cpu_to_le32(virt);
398 *(__le32 *)(&p->write[off]) = cpu_to_le32(write);
399 }
400
401 /*
402 * Restore the *real* BARs after we detect a FLR or backdoor reset.
403 * (backdoor = some device specific technique that we didn't catch)
404 */
405 static void vfio_bar_restore(struct vfio_pci_device *vdev)
406 {
407 struct pci_dev *pdev = vdev->pdev;
408 u32 *rbar = vdev->rbar;
409 u16 cmd;
410 int i;
411
412 if (pdev->is_virtfn)
413 return;
414
415 pr_info("%s: %s reset recovery - restoring bars\n",
416 __func__, dev_name(&pdev->dev));
417
418 for (i = PCI_BASE_ADDRESS_0; i <= PCI_BASE_ADDRESS_5; i += 4, rbar++)
419 pci_user_write_config_dword(pdev, i, *rbar);
420
421 pci_user_write_config_dword(pdev, PCI_ROM_ADDRESS, *rbar);
422
423 if (vdev->nointx) {
424 pci_user_read_config_word(pdev, PCI_COMMAND, &cmd);
425 cmd |= PCI_COMMAND_INTX_DISABLE;
426 pci_user_write_config_word(pdev, PCI_COMMAND, cmd);
427 }
428 }
429
430 static __le32 vfio_generate_bar_flags(struct pci_dev *pdev, int bar)
431 {
432 unsigned long flags = pci_resource_flags(pdev, bar);
433 u32 val;
434
435 if (flags & IORESOURCE_IO)
436 return cpu_to_le32(PCI_BASE_ADDRESS_SPACE_IO);
437
438 val = PCI_BASE_ADDRESS_SPACE_MEMORY;
439
440 if (flags & IORESOURCE_PREFETCH)
441 val |= PCI_BASE_ADDRESS_MEM_PREFETCH;
442
443 if (flags & IORESOURCE_MEM_64)
444 val |= PCI_BASE_ADDRESS_MEM_TYPE_64;
445
446 return cpu_to_le32(val);
447 }
448
449 /*
450 * Pretend we're hardware and tweak the values of the *virtual* PCI BARs
451 * to reflect the hardware capabilities. This implements BAR sizing.
452 */
453 static void vfio_bar_fixup(struct vfio_pci_device *vdev)
454 {
455 struct pci_dev *pdev = vdev->pdev;
456 int i;
457 __le32 *bar;
458 u64 mask;
459
460 bar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0];
461
462 for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++, bar++) {
463 if (!pci_resource_start(pdev, i)) {
464 *bar = 0; /* Unmapped by host = unimplemented to user */
465 continue;
466 }
467
468 mask = ~(pci_resource_len(pdev, i) - 1);
469
470 *bar &= cpu_to_le32((u32)mask);
471 *bar |= vfio_generate_bar_flags(pdev, i);
472
473 if (*bar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
474 bar++;
475 *bar &= cpu_to_le32((u32)(mask >> 32));
476 i++;
477 }
478 }
479
480 bar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];
481
482 /*
483 * NB. REGION_INFO will have reported zero size if we weren't able
484 * to read the ROM, but we still return the actual BAR size here if
485 * it exists (or the shadow ROM space).
486 */
487 if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) {
488 mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1);
489 mask |= PCI_ROM_ADDRESS_ENABLE;
490 *bar &= cpu_to_le32((u32)mask);
491 } else if (pdev->resource[PCI_ROM_RESOURCE].flags &
492 IORESOURCE_ROM_SHADOW) {
493 mask = ~(0x20000 - 1);
494 mask |= PCI_ROM_ADDRESS_ENABLE;
495 *bar &= cpu_to_le32((u32)mask);
496 } else
497 *bar = 0;
498
499 vdev->bardirty = false;
500 }
501
502 static int vfio_basic_config_read(struct vfio_pci_device *vdev, int pos,
503 int count, struct perm_bits *perm,
504 int offset, __le32 *val)
505 {
506 if (is_bar(offset)) /* pos == offset for basic config */
507 vfio_bar_fixup(vdev);
508
509 count = vfio_default_config_read(vdev, pos, count, perm, offset, val);
510
511 /* Mask in virtual memory enable for SR-IOV devices */
512 if (offset == PCI_COMMAND && vdev->pdev->is_virtfn) {
513 u16 cmd = le16_to_cpu(*(__le16 *)&vdev->vconfig[PCI_COMMAND]);
514 u32 tmp_val = le32_to_cpu(*val);
515
516 tmp_val |= cmd & PCI_COMMAND_MEMORY;
517 *val = cpu_to_le32(tmp_val);
518 }
519
520 return count;
521 }
522
523 /* Test whether BARs match the value we think they should contain */
524 static bool vfio_need_bar_restore(struct vfio_pci_device *vdev)
525 {
526 int i = 0, pos = PCI_BASE_ADDRESS_0, ret;
527 u32 bar;
528
529 for (; pos <= PCI_BASE_ADDRESS_5; i++, pos += 4) {
530 if (vdev->rbar[i]) {
531 ret = pci_user_read_config_dword(vdev->pdev, pos, &bar);
532 if (ret || vdev->rbar[i] != bar)
533 return true;
534 }
535 }
536
537 return false;
538 }
539
540 static int vfio_basic_config_write(struct vfio_pci_device *vdev, int pos,
541 int count, struct perm_bits *perm,
542 int offset, __le32 val)
543 {
544 struct pci_dev *pdev = vdev->pdev;
545 __le16 *virt_cmd;
546 u16 new_cmd = 0;
547 int ret;
548
549 virt_cmd = (__le16 *)&vdev->vconfig[PCI_COMMAND];
550
551 if (offset == PCI_COMMAND) {
552 bool phys_mem, virt_mem, new_mem, phys_io, virt_io, new_io;
553 u16 phys_cmd;
554
555 ret = pci_user_read_config_word(pdev, PCI_COMMAND, &phys_cmd);
556 if (ret)
557 return ret;
558
559 new_cmd = le32_to_cpu(val);
560
561 phys_mem = !!(phys_cmd & PCI_COMMAND_MEMORY);
562 virt_mem = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_MEMORY);
563 new_mem = !!(new_cmd & PCI_COMMAND_MEMORY);
564
565 phys_io = !!(phys_cmd & PCI_COMMAND_IO);
566 virt_io = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_IO);
567 new_io = !!(new_cmd & PCI_COMMAND_IO);
568
569 /*
570 * If the user is writing mem/io enable (new_mem/io) and we
571 * think it's already enabled (virt_mem/io), but the hardware
572 * shows it disabled (phys_mem/io, then the device has
573 * undergone some kind of backdoor reset and needs to be
574 * restored before we allow it to enable the bars.
575 * SR-IOV devices will trigger this, but we catch them later
576 */
577 if ((new_mem && virt_mem && !phys_mem) ||
578 (new_io && virt_io && !phys_io) ||
579 vfio_need_bar_restore(vdev))
580 vfio_bar_restore(vdev);
581 }
582
583 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
584 if (count < 0)
585 return count;
586
587 /*
588 * Save current memory/io enable bits in vconfig to allow for
589 * the test above next time.
590 */
591 if (offset == PCI_COMMAND) {
592 u16 mask = PCI_COMMAND_MEMORY | PCI_COMMAND_IO;
593
594 *virt_cmd &= cpu_to_le16(~mask);
595 *virt_cmd |= cpu_to_le16(new_cmd & mask);
596 }
597
598 /* Emulate INTx disable */
599 if (offset >= PCI_COMMAND && offset <= PCI_COMMAND + 1) {
600 bool virt_intx_disable;
601
602 virt_intx_disable = !!(le16_to_cpu(*virt_cmd) &
603 PCI_COMMAND_INTX_DISABLE);
604
605 if (virt_intx_disable && !vdev->virq_disabled) {
606 vdev->virq_disabled = true;
607 vfio_pci_intx_mask(vdev);
608 } else if (!virt_intx_disable && vdev->virq_disabled) {
609 vdev->virq_disabled = false;
610 vfio_pci_intx_unmask(vdev);
611 }
612 }
613
614 if (is_bar(offset))
615 vdev->bardirty = true;
616
617 return count;
618 }
619
620 /* Permissions for the Basic PCI Header */
621 static int __init init_pci_cap_basic_perm(struct perm_bits *perm)
622 {
623 if (alloc_perm_bits(perm, PCI_STD_HEADER_SIZEOF))
624 return -ENOMEM;
625
626 perm->readfn = vfio_basic_config_read;
627 perm->writefn = vfio_basic_config_write;
628
629 /* Virtualized for SR-IOV functions, which just have FFFF */
630 p_setw(perm, PCI_VENDOR_ID, (u16)ALL_VIRT, NO_WRITE);
631 p_setw(perm, PCI_DEVICE_ID, (u16)ALL_VIRT, NO_WRITE);
632
633 /*
634 * Virtualize INTx disable, we use it internally for interrupt
635 * control and can emulate it for non-PCI 2.3 devices.
636 */
637 p_setw(perm, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE, (u16)ALL_WRITE);
638
639 /* Virtualize capability list, we might want to skip/disable */
640 p_setw(perm, PCI_STATUS, PCI_STATUS_CAP_LIST, NO_WRITE);
641
642 /* No harm to write */
643 p_setb(perm, PCI_CACHE_LINE_SIZE, NO_VIRT, (u8)ALL_WRITE);
644 p_setb(perm, PCI_LATENCY_TIMER, NO_VIRT, (u8)ALL_WRITE);
645 p_setb(perm, PCI_BIST, NO_VIRT, (u8)ALL_WRITE);
646
647 /* Virtualize all bars, can't touch the real ones */
648 p_setd(perm, PCI_BASE_ADDRESS_0, ALL_VIRT, ALL_WRITE);
649 p_setd(perm, PCI_BASE_ADDRESS_1, ALL_VIRT, ALL_WRITE);
650 p_setd(perm, PCI_BASE_ADDRESS_2, ALL_VIRT, ALL_WRITE);
651 p_setd(perm, PCI_BASE_ADDRESS_3, ALL_VIRT, ALL_WRITE);
652 p_setd(perm, PCI_BASE_ADDRESS_4, ALL_VIRT, ALL_WRITE);
653 p_setd(perm, PCI_BASE_ADDRESS_5, ALL_VIRT, ALL_WRITE);
654 p_setd(perm, PCI_ROM_ADDRESS, ALL_VIRT, ALL_WRITE);
655
656 /* Allow us to adjust capability chain */
657 p_setb(perm, PCI_CAPABILITY_LIST, (u8)ALL_VIRT, NO_WRITE);
658
659 /* Sometimes used by sw, just virtualize */
660 p_setb(perm, PCI_INTERRUPT_LINE, (u8)ALL_VIRT, (u8)ALL_WRITE);
661
662 /* Virtualize interrupt pin to allow hiding INTx */
663 p_setb(perm, PCI_INTERRUPT_PIN, (u8)ALL_VIRT, (u8)NO_WRITE);
664
665 return 0;
666 }
667
668 static int vfio_pm_config_write(struct vfio_pci_device *vdev, int pos,
669 int count, struct perm_bits *perm,
670 int offset, __le32 val)
671 {
672 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
673 if (count < 0)
674 return count;
675
676 if (offset == PCI_PM_CTRL) {
677 pci_power_t state;
678
679 switch (le32_to_cpu(val) & PCI_PM_CTRL_STATE_MASK) {
680 case 0:
681 state = PCI_D0;
682 break;
683 case 1:
684 state = PCI_D1;
685 break;
686 case 2:
687 state = PCI_D2;
688 break;
689 case 3:
690 state = PCI_D3hot;
691 break;
692 }
693
694 pci_set_power_state(vdev->pdev, state);
695 }
696
697 return count;
698 }
699
700 /* Permissions for the Power Management capability */
701 static int __init init_pci_cap_pm_perm(struct perm_bits *perm)
702 {
703 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_PM]))
704 return -ENOMEM;
705
706 perm->writefn = vfio_pm_config_write;
707
708 /*
709 * We always virtualize the next field so we can remove
710 * capabilities from the chain if we want to.
711 */
712 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
713
714 /*
715 * Power management is defined *per function*, so we can let
716 * the user change power state, but we trap and initiate the
717 * change ourselves, so the state bits are read-only.
718 */
719 p_setd(perm, PCI_PM_CTRL, NO_VIRT, ~PCI_PM_CTRL_STATE_MASK);
720 return 0;
721 }
722
723 static int vfio_vpd_config_write(struct vfio_pci_device *vdev, int pos,
724 int count, struct perm_bits *perm,
725 int offset, __le32 val)
726 {
727 struct pci_dev *pdev = vdev->pdev;
728 __le16 *paddr = (__le16 *)(vdev->vconfig + pos - offset + PCI_VPD_ADDR);
729 __le32 *pdata = (__le32 *)(vdev->vconfig + pos - offset + PCI_VPD_DATA);
730 u16 addr;
731 u32 data;
732
733 /*
734 * Write through to emulation. If the write includes the upper byte
735 * of PCI_VPD_ADDR, then the PCI_VPD_ADDR_F bit is written and we
736 * have work to do.
737 */
738 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
739 if (count < 0 || offset > PCI_VPD_ADDR + 1 ||
740 offset + count <= PCI_VPD_ADDR + 1)
741 return count;
742
743 addr = le16_to_cpu(*paddr);
744
745 if (addr & PCI_VPD_ADDR_F) {
746 data = le32_to_cpu(*pdata);
747 if (pci_write_vpd(pdev, addr & ~PCI_VPD_ADDR_F, 4, &data) != 4)
748 return count;
749 } else {
750 data = 0;
751 if (pci_read_vpd(pdev, addr, 4, &data) < 0)
752 return count;
753 *pdata = cpu_to_le32(data);
754 }
755
756 /*
757 * Toggle PCI_VPD_ADDR_F in the emulated PCI_VPD_ADDR register to
758 * signal completion. If an error occurs above, we assume that not
759 * toggling this bit will induce a driver timeout.
760 */
761 addr ^= PCI_VPD_ADDR_F;
762 *paddr = cpu_to_le16(addr);
763
764 return count;
765 }
766
767 /* Permissions for Vital Product Data capability */
768 static int __init init_pci_cap_vpd_perm(struct perm_bits *perm)
769 {
770 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_VPD]))
771 return -ENOMEM;
772
773 perm->writefn = vfio_vpd_config_write;
774
775 /*
776 * We always virtualize the next field so we can remove
777 * capabilities from the chain if we want to.
778 */
779 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
780
781 /*
782 * Both the address and data registers are virtualized to
783 * enable access through the pci_vpd_read/write functions
784 */
785 p_setw(perm, PCI_VPD_ADDR, (u16)ALL_VIRT, (u16)ALL_WRITE);
786 p_setd(perm, PCI_VPD_DATA, ALL_VIRT, ALL_WRITE);
787
788 return 0;
789 }
790
791 /* Permissions for PCI-X capability */
792 static int __init init_pci_cap_pcix_perm(struct perm_bits *perm)
793 {
794 /* Alloc 24, but only 8 are used in v0 */
795 if (alloc_perm_bits(perm, PCI_CAP_PCIX_SIZEOF_V2))
796 return -ENOMEM;
797
798 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
799
800 p_setw(perm, PCI_X_CMD, NO_VIRT, (u16)ALL_WRITE);
801 p_setd(perm, PCI_X_ECC_CSR, NO_VIRT, ALL_WRITE);
802 return 0;
803 }
804
805 static int vfio_exp_config_write(struct vfio_pci_device *vdev, int pos,
806 int count, struct perm_bits *perm,
807 int offset, __le32 val)
808 {
809 __le16 *ctrl = (__le16 *)(vdev->vconfig + pos -
810 offset + PCI_EXP_DEVCTL);
811
812 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
813 if (count < 0)
814 return count;
815
816 /*
817 * The FLR bit is virtualized, if set and the device supports PCIe
818 * FLR, issue a reset_function. Regardless, clear the bit, the spec
819 * requires it to be always read as zero. NB, reset_function might
820 * not use a PCIe FLR, we don't have that level of granularity.
821 */
822 if (*ctrl & cpu_to_le16(PCI_EXP_DEVCTL_BCR_FLR)) {
823 u32 cap;
824 int ret;
825
826 *ctrl &= ~cpu_to_le16(PCI_EXP_DEVCTL_BCR_FLR);
827
828 ret = pci_user_read_config_dword(vdev->pdev,
829 pos - offset + PCI_EXP_DEVCAP,
830 &cap);
831
832 if (!ret && (cap & PCI_EXP_DEVCAP_FLR))
833 pci_try_reset_function(vdev->pdev);
834 }
835
836 return count;
837 }
838
839 /* Permissions for PCI Express capability */
840 static int __init init_pci_cap_exp_perm(struct perm_bits *perm)
841 {
842 /* Alloc largest of possible sizes */
843 if (alloc_perm_bits(perm, PCI_CAP_EXP_ENDPOINT_SIZEOF_V2))
844 return -ENOMEM;
845
846 perm->writefn = vfio_exp_config_write;
847
848 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
849
850 /*
851 * Allow writes to device control fields, except devctl_phantom,
852 * which could confuse IOMMU, and the ARI bit in devctl2, which
853 * is set at probe time. FLR gets virtualized via our writefn.
854 */
855 p_setw(perm, PCI_EXP_DEVCTL,
856 PCI_EXP_DEVCTL_BCR_FLR, ~PCI_EXP_DEVCTL_PHANTOM);
857 p_setw(perm, PCI_EXP_DEVCTL2, NO_VIRT, ~PCI_EXP_DEVCTL2_ARI);
858 return 0;
859 }
860
861 static int vfio_af_config_write(struct vfio_pci_device *vdev, int pos,
862 int count, struct perm_bits *perm,
863 int offset, __le32 val)
864 {
865 u8 *ctrl = vdev->vconfig + pos - offset + PCI_AF_CTRL;
866
867 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
868 if (count < 0)
869 return count;
870
871 /*
872 * The FLR bit is virtualized, if set and the device supports AF
873 * FLR, issue a reset_function. Regardless, clear the bit, the spec
874 * requires it to be always read as zero. NB, reset_function might
875 * not use an AF FLR, we don't have that level of granularity.
876 */
877 if (*ctrl & PCI_AF_CTRL_FLR) {
878 u8 cap;
879 int ret;
880
881 *ctrl &= ~PCI_AF_CTRL_FLR;
882
883 ret = pci_user_read_config_byte(vdev->pdev,
884 pos - offset + PCI_AF_CAP,
885 &cap);
886
887 if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP))
888 pci_try_reset_function(vdev->pdev);
889 }
890
891 return count;
892 }
893
894 /* Permissions for Advanced Function capability */
895 static int __init init_pci_cap_af_perm(struct perm_bits *perm)
896 {
897 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_AF]))
898 return -ENOMEM;
899
900 perm->writefn = vfio_af_config_write;
901
902 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
903 p_setb(perm, PCI_AF_CTRL, PCI_AF_CTRL_FLR, PCI_AF_CTRL_FLR);
904 return 0;
905 }
906
907 /* Permissions for Advanced Error Reporting extended capability */
908 static int __init init_pci_ext_cap_err_perm(struct perm_bits *perm)
909 {
910 u32 mask;
911
912 if (alloc_perm_bits(perm, pci_ext_cap_length[PCI_EXT_CAP_ID_ERR]))
913 return -ENOMEM;
914
915 /*
916 * Virtualize the first dword of all express capabilities
917 * because it includes the next pointer. This lets us later
918 * remove capabilities from the chain if we need to.
919 */
920 p_setd(perm, 0, ALL_VIRT, NO_WRITE);
921
922 /* Writable bits mask */
923 mask = PCI_ERR_UNC_UND | /* Undefined */
924 PCI_ERR_UNC_DLP | /* Data Link Protocol */
925 PCI_ERR_UNC_SURPDN | /* Surprise Down */
926 PCI_ERR_UNC_POISON_TLP | /* Poisoned TLP */
927 PCI_ERR_UNC_FCP | /* Flow Control Protocol */
928 PCI_ERR_UNC_COMP_TIME | /* Completion Timeout */
929 PCI_ERR_UNC_COMP_ABORT | /* Completer Abort */
930 PCI_ERR_UNC_UNX_COMP | /* Unexpected Completion */
931 PCI_ERR_UNC_RX_OVER | /* Receiver Overflow */
932 PCI_ERR_UNC_MALF_TLP | /* Malformed TLP */
933 PCI_ERR_UNC_ECRC | /* ECRC Error Status */
934 PCI_ERR_UNC_UNSUP | /* Unsupported Request */
935 PCI_ERR_UNC_ACSV | /* ACS Violation */
936 PCI_ERR_UNC_INTN | /* internal error */
937 PCI_ERR_UNC_MCBTLP | /* MC blocked TLP */
938 PCI_ERR_UNC_ATOMEG | /* Atomic egress blocked */
939 PCI_ERR_UNC_TLPPRE; /* TLP prefix blocked */
940 p_setd(perm, PCI_ERR_UNCOR_STATUS, NO_VIRT, mask);
941 p_setd(perm, PCI_ERR_UNCOR_MASK, NO_VIRT, mask);
942 p_setd(perm, PCI_ERR_UNCOR_SEVER, NO_VIRT, mask);
943
944 mask = PCI_ERR_COR_RCVR | /* Receiver Error Status */
945 PCI_ERR_COR_BAD_TLP | /* Bad TLP Status */
946 PCI_ERR_COR_BAD_DLLP | /* Bad DLLP Status */
947 PCI_ERR_COR_REP_ROLL | /* REPLAY_NUM Rollover */
948 PCI_ERR_COR_REP_TIMER | /* Replay Timer Timeout */
949 PCI_ERR_COR_ADV_NFAT | /* Advisory Non-Fatal */
950 PCI_ERR_COR_INTERNAL | /* Corrected Internal */
951 PCI_ERR_COR_LOG_OVER; /* Header Log Overflow */
952 p_setd(perm, PCI_ERR_COR_STATUS, NO_VIRT, mask);
953 p_setd(perm, PCI_ERR_COR_MASK, NO_VIRT, mask);
954
955 mask = PCI_ERR_CAP_ECRC_GENE | /* ECRC Generation Enable */
956 PCI_ERR_CAP_ECRC_CHKE; /* ECRC Check Enable */
957 p_setd(perm, PCI_ERR_CAP, NO_VIRT, mask);
958 return 0;
959 }
960
961 /* Permissions for Power Budgeting extended capability */
962 static int __init init_pci_ext_cap_pwr_perm(struct perm_bits *perm)
963 {
964 if (alloc_perm_bits(perm, pci_ext_cap_length[PCI_EXT_CAP_ID_PWR]))
965 return -ENOMEM;
966
967 p_setd(perm, 0, ALL_VIRT, NO_WRITE);
968
969 /* Writing the data selector is OK, the info is still read-only */
970 p_setb(perm, PCI_PWR_DATA, NO_VIRT, (u8)ALL_WRITE);
971 return 0;
972 }
973
974 /*
975 * Initialize the shared permission tables
976 */
977 void vfio_pci_uninit_perm_bits(void)
978 {
979 free_perm_bits(&cap_perms[PCI_CAP_ID_BASIC]);
980
981 free_perm_bits(&cap_perms[PCI_CAP_ID_PM]);
982 free_perm_bits(&cap_perms[PCI_CAP_ID_VPD]);
983 free_perm_bits(&cap_perms[PCI_CAP_ID_PCIX]);
984 free_perm_bits(&cap_perms[PCI_CAP_ID_EXP]);
985 free_perm_bits(&cap_perms[PCI_CAP_ID_AF]);
986
987 free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_ERR]);
988 free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_PWR]);
989 }
990
991 int __init vfio_pci_init_perm_bits(void)
992 {
993 int ret;
994
995 /* Basic config space */
996 ret = init_pci_cap_basic_perm(&cap_perms[PCI_CAP_ID_BASIC]);
997
998 /* Capabilities */
999 ret |= init_pci_cap_pm_perm(&cap_perms[PCI_CAP_ID_PM]);
1000 ret |= init_pci_cap_vpd_perm(&cap_perms[PCI_CAP_ID_VPD]);
1001 ret |= init_pci_cap_pcix_perm(&cap_perms[PCI_CAP_ID_PCIX]);
1002 cap_perms[PCI_CAP_ID_VNDR].writefn = vfio_raw_config_write;
1003 ret |= init_pci_cap_exp_perm(&cap_perms[PCI_CAP_ID_EXP]);
1004 ret |= init_pci_cap_af_perm(&cap_perms[PCI_CAP_ID_AF]);
1005
1006 /* Extended capabilities */
1007 ret |= init_pci_ext_cap_err_perm(&ecap_perms[PCI_EXT_CAP_ID_ERR]);
1008 ret |= init_pci_ext_cap_pwr_perm(&ecap_perms[PCI_EXT_CAP_ID_PWR]);
1009 ecap_perms[PCI_EXT_CAP_ID_VNDR].writefn = vfio_raw_config_write;
1010
1011 if (ret)
1012 vfio_pci_uninit_perm_bits();
1013
1014 return ret;
1015 }
1016
1017 static int vfio_find_cap_start(struct vfio_pci_device *vdev, int pos)
1018 {
1019 u8 cap;
1020 int base = (pos >= PCI_CFG_SPACE_SIZE) ? PCI_CFG_SPACE_SIZE :
1021 PCI_STD_HEADER_SIZEOF;
1022 cap = vdev->pci_config_map[pos];
1023
1024 if (cap == PCI_CAP_ID_BASIC)
1025 return 0;
1026
1027 /* XXX Can we have to abutting capabilities of the same type? */
1028 while (pos - 1 >= base && vdev->pci_config_map[pos - 1] == cap)
1029 pos--;
1030
1031 return pos;
1032 }
1033
1034 static int vfio_msi_config_read(struct vfio_pci_device *vdev, int pos,
1035 int count, struct perm_bits *perm,
1036 int offset, __le32 *val)
1037 {
1038 /* Update max available queue size from msi_qmax */
1039 if (offset <= PCI_MSI_FLAGS && offset + count >= PCI_MSI_FLAGS) {
1040 __le16 *flags;
1041 int start;
1042
1043 start = vfio_find_cap_start(vdev, pos);
1044
1045 flags = (__le16 *)&vdev->vconfig[start];
1046
1047 *flags &= cpu_to_le16(~PCI_MSI_FLAGS_QMASK);
1048 *flags |= cpu_to_le16(vdev->msi_qmax << 1);
1049 }
1050
1051 return vfio_default_config_read(vdev, pos, count, perm, offset, val);
1052 }
1053
1054 static int vfio_msi_config_write(struct vfio_pci_device *vdev, int pos,
1055 int count, struct perm_bits *perm,
1056 int offset, __le32 val)
1057 {
1058 count = vfio_default_config_write(vdev, pos, count, perm, offset, val);
1059 if (count < 0)
1060 return count;
1061
1062 /* Fixup and write configured queue size and enable to hardware */
1063 if (offset <= PCI_MSI_FLAGS && offset + count >= PCI_MSI_FLAGS) {
1064 __le16 *pflags;
1065 u16 flags;
1066 int start, ret;
1067
1068 start = vfio_find_cap_start(vdev, pos);
1069
1070 pflags = (__le16 *)&vdev->vconfig[start + PCI_MSI_FLAGS];
1071
1072 flags = le16_to_cpu(*pflags);
1073
1074 /* MSI is enabled via ioctl */
1075 if (!is_msi(vdev))
1076 flags &= ~PCI_MSI_FLAGS_ENABLE;
1077
1078 /* Check queue size */
1079 if ((flags & PCI_MSI_FLAGS_QSIZE) >> 4 > vdev->msi_qmax) {
1080 flags &= ~PCI_MSI_FLAGS_QSIZE;
1081 flags |= vdev->msi_qmax << 4;
1082 }
1083
1084 /* Write back to virt and to hardware */
1085 *pflags = cpu_to_le16(flags);
1086 ret = pci_user_write_config_word(vdev->pdev,
1087 start + PCI_MSI_FLAGS,
1088 flags);
1089 if (ret)
1090 return ret;
1091 }
1092
1093 return count;
1094 }
1095
1096 /*
1097 * MSI determination is per-device, so this routine gets used beyond
1098 * initialization time. Don't add __init
1099 */
1100 static int init_pci_cap_msi_perm(struct perm_bits *perm, int len, u16 flags)
1101 {
1102 if (alloc_perm_bits(perm, len))
1103 return -ENOMEM;
1104
1105 perm->readfn = vfio_msi_config_read;
1106 perm->writefn = vfio_msi_config_write;
1107
1108 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE);
1109
1110 /*
1111 * The upper byte of the control register is reserved,
1112 * just setup the lower byte.
1113 */
1114 p_setb(perm, PCI_MSI_FLAGS, (u8)ALL_VIRT, (u8)ALL_WRITE);
1115 p_setd(perm, PCI_MSI_ADDRESS_LO, ALL_VIRT, ALL_WRITE);
1116 if (flags & PCI_MSI_FLAGS_64BIT) {
1117 p_setd(perm, PCI_MSI_ADDRESS_HI, ALL_VIRT, ALL_WRITE);
1118 p_setw(perm, PCI_MSI_DATA_64, (u16)ALL_VIRT, (u16)ALL_WRITE);
1119 if (flags & PCI_MSI_FLAGS_MASKBIT) {
1120 p_setd(perm, PCI_MSI_MASK_64, NO_VIRT, ALL_WRITE);
1121 p_setd(perm, PCI_MSI_PENDING_64, NO_VIRT, ALL_WRITE);
1122 }
1123 } else {
1124 p_setw(perm, PCI_MSI_DATA_32, (u16)ALL_VIRT, (u16)ALL_WRITE);
1125 if (flags & PCI_MSI_FLAGS_MASKBIT) {
1126 p_setd(perm, PCI_MSI_MASK_32, NO_VIRT, ALL_WRITE);
1127 p_setd(perm, PCI_MSI_PENDING_32, NO_VIRT, ALL_WRITE);
1128 }
1129 }
1130 return 0;
1131 }
1132
1133 /* Determine MSI CAP field length; initialize msi_perms on 1st call per vdev */
1134 static int vfio_msi_cap_len(struct vfio_pci_device *vdev, u8 pos)
1135 {
1136 struct pci_dev *pdev = vdev->pdev;
1137 int len, ret;
1138 u16 flags;
1139
1140 ret = pci_read_config_word(pdev, pos + PCI_MSI_FLAGS, &flags);
1141 if (ret)
1142 return pcibios_err_to_errno(ret);
1143
1144 len = 10; /* Minimum size */
1145 if (flags & PCI_MSI_FLAGS_64BIT)
1146 len += 4;
1147 if (flags & PCI_MSI_FLAGS_MASKBIT)
1148 len += 10;
1149
1150 if (vdev->msi_perm)
1151 return len;
1152
1153 vdev->msi_perm = kmalloc(sizeof(struct perm_bits), GFP_KERNEL);
1154 if (!vdev->msi_perm)
1155 return -ENOMEM;
1156
1157 ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);
1158 if (ret)
1159 return ret;
1160
1161 return len;
1162 }
1163
1164 /* Determine extended capability length for VC (2 & 9) and MFVC */
1165 static int vfio_vc_cap_len(struct vfio_pci_device *vdev, u16 pos)
1166 {
1167 struct pci_dev *pdev = vdev->pdev;
1168 u32 tmp;
1169 int ret, evcc, phases, vc_arb;
1170 int len = PCI_CAP_VC_BASE_SIZEOF;
1171
1172 ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP1, &tmp);
1173 if (ret)
1174 return pcibios_err_to_errno(ret);
1175
1176 evcc = tmp & PCI_VC_CAP1_EVCC; /* extended vc count */
1177 ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP2, &tmp);
1178 if (ret)
1179 return pcibios_err_to_errno(ret);
1180
1181 if (tmp & PCI_VC_CAP2_128_PHASE)
1182 phases = 128;
1183 else if (tmp & PCI_VC_CAP2_64_PHASE)
1184 phases = 64;
1185 else if (tmp & PCI_VC_CAP2_32_PHASE)
1186 phases = 32;
1187 else
1188 phases = 0;
1189
1190 vc_arb = phases * 4;
1191
1192 /*
1193 * Port arbitration tables are root & switch only;
1194 * function arbitration tables are function 0 only.
1195 * In either case, we'll never let user write them so
1196 * we don't care how big they are
1197 */
1198 len += (1 + evcc) * PCI_CAP_VC_PER_VC_SIZEOF;
1199 if (vc_arb) {
1200 len = round_up(len, 16);
1201 len += vc_arb / 8;
1202 }
1203 return len;
1204 }
1205
1206 static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
1207 {
1208 struct pci_dev *pdev = vdev->pdev;
1209 u32 dword;
1210 u16 word;
1211 u8 byte;
1212 int ret;
1213
1214 switch (cap) {
1215 case PCI_CAP_ID_MSI:
1216 return vfio_msi_cap_len(vdev, pos);
1217 case PCI_CAP_ID_PCIX:
1218 ret = pci_read_config_word(pdev, pos + PCI_X_CMD, &word);
1219 if (ret)
1220 return pcibios_err_to_errno(ret);
1221
1222 if (PCI_X_CMD_VERSION(word)) {
1223 if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) {
1224 /* Test for extended capabilities */
1225 pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE,
1226 &dword);
1227 vdev->extended_caps = (dword != 0);
1228 }
1229 return PCI_CAP_PCIX_SIZEOF_V2;
1230 } else
1231 return PCI_CAP_PCIX_SIZEOF_V0;
1232 case PCI_CAP_ID_VNDR:
1233 /* length follows next field */
1234 ret = pci_read_config_byte(pdev, pos + PCI_CAP_FLAGS, &byte);
1235 if (ret)
1236 return pcibios_err_to_errno(ret);
1237
1238 return byte;
1239 case PCI_CAP_ID_EXP:
1240 if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) {
1241 /* Test for extended capabilities */
1242 pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword);
1243 vdev->extended_caps = (dword != 0);
1244 }
1245
1246 /* length based on version and type */
1247 if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) {
1248 if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
1249 return 0xc; /* "All Devices" only, no link */
1250 return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1;
1251 } else {
1252 if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
1253 return 0x2c; /* No link */
1254 return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2;
1255 }
1256 case PCI_CAP_ID_HT:
1257 ret = pci_read_config_byte(pdev, pos + 3, &byte);
1258 if (ret)
1259 return pcibios_err_to_errno(ret);
1260
1261 return (byte & HT_3BIT_CAP_MASK) ?
1262 HT_CAP_SIZEOF_SHORT : HT_CAP_SIZEOF_LONG;
1263 case PCI_CAP_ID_SATA:
1264 ret = pci_read_config_byte(pdev, pos + PCI_SATA_REGS, &byte);
1265 if (ret)
1266 return pcibios_err_to_errno(ret);
1267
1268 byte &= PCI_SATA_REGS_MASK;
1269 if (byte == PCI_SATA_REGS_INLINE)
1270 return PCI_SATA_SIZEOF_LONG;
1271 else
1272 return PCI_SATA_SIZEOF_SHORT;
1273 default:
1274 pr_warn("%s: %s unknown length for pci cap 0x%x@0x%x\n",
1275 dev_name(&pdev->dev), __func__, cap, pos);
1276 }
1277
1278 return 0;
1279 }
1280
1281 static int vfio_ext_cap_len(struct vfio_pci_device *vdev, u16 ecap, u16 epos)
1282 {
1283 struct pci_dev *pdev = vdev->pdev;
1284 u8 byte;
1285 u32 dword;
1286 int ret;
1287
1288 switch (ecap) {
1289 case PCI_EXT_CAP_ID_VNDR:
1290 ret = pci_read_config_dword(pdev, epos + PCI_VSEC_HDR, &dword);
1291 if (ret)
1292 return pcibios_err_to_errno(ret);
1293
1294 return dword >> PCI_VSEC_HDR_LEN_SHIFT;
1295 case PCI_EXT_CAP_ID_VC:
1296 case PCI_EXT_CAP_ID_VC9:
1297 case PCI_EXT_CAP_ID_MFVC:
1298 return vfio_vc_cap_len(vdev, epos);
1299 case PCI_EXT_CAP_ID_ACS:
1300 ret = pci_read_config_byte(pdev, epos + PCI_ACS_CAP, &byte);
1301 if (ret)
1302 return pcibios_err_to_errno(ret);
1303
1304 if (byte & PCI_ACS_EC) {
1305 int bits;
1306
1307 ret = pci_read_config_byte(pdev,
1308 epos + PCI_ACS_EGRESS_BITS,
1309 &byte);
1310 if (ret)
1311 return pcibios_err_to_errno(ret);
1312
1313 bits = byte ? round_up(byte, 32) : 256;
1314 return 8 + (bits / 8);
1315 }
1316 return 8;
1317
1318 case PCI_EXT_CAP_ID_REBAR:
1319 ret = pci_read_config_byte(pdev, epos + PCI_REBAR_CTRL, &byte);
1320 if (ret)
1321 return pcibios_err_to_errno(ret);
1322
1323 byte &= PCI_REBAR_CTRL_NBAR_MASK;
1324 byte >>= PCI_REBAR_CTRL_NBAR_SHIFT;
1325
1326 return 4 + (byte * 8);
1327 case PCI_EXT_CAP_ID_DPA:
1328 ret = pci_read_config_byte(pdev, epos + PCI_DPA_CAP, &byte);
1329 if (ret)
1330 return pcibios_err_to_errno(ret);
1331
1332 byte &= PCI_DPA_CAP_SUBSTATE_MASK;
1333 return PCI_DPA_BASE_SIZEOF + byte + 1;
1334 case PCI_EXT_CAP_ID_TPH:
1335 ret = pci_read_config_dword(pdev, epos + PCI_TPH_CAP, &dword);
1336 if (ret)
1337 return pcibios_err_to_errno(ret);
1338
1339 if ((dword & PCI_TPH_CAP_LOC_MASK) == PCI_TPH_LOC_CAP) {
1340 int sts;
1341
1342 sts = dword & PCI_TPH_CAP_ST_MASK;
1343 sts >>= PCI_TPH_CAP_ST_SHIFT;
1344 return PCI_TPH_BASE_SIZEOF + (sts * 2) + 2;
1345 }
1346 return PCI_TPH_BASE_SIZEOF;
1347 default:
1348 pr_warn("%s: %s unknown length for pci ecap 0x%x@0x%x\n",
1349 dev_name(&pdev->dev), __func__, ecap, epos);
1350 }
1351
1352 return 0;
1353 }
1354
1355 static int vfio_fill_vconfig_bytes(struct vfio_pci_device *vdev,
1356 int offset, int size)
1357 {
1358 struct pci_dev *pdev = vdev->pdev;
1359 int ret = 0;
1360
1361 /*
1362 * We try to read physical config space in the largest chunks
1363 * we can, assuming that all of the fields support dword access.
1364 * pci_save_state() makes this same assumption and seems to do ok.
1365 */
1366 while (size) {
1367 int filled;
1368
1369 if (size >= 4 && !(offset % 4)) {
1370 __le32 *dwordp = (__le32 *)&vdev->vconfig[offset];
1371 u32 dword;
1372
1373 ret = pci_read_config_dword(pdev, offset, &dword);
1374 if (ret)
1375 return ret;
1376 *dwordp = cpu_to_le32(dword);
1377 filled = 4;
1378 } else if (size >= 2 && !(offset % 2)) {
1379 __le16 *wordp = (__le16 *)&vdev->vconfig[offset];
1380 u16 word;
1381
1382 ret = pci_read_config_word(pdev, offset, &word);
1383 if (ret)
1384 return ret;
1385 *wordp = cpu_to_le16(word);
1386 filled = 2;
1387 } else {
1388 u8 *byte = &vdev->vconfig[offset];
1389 ret = pci_read_config_byte(pdev, offset, byte);
1390 if (ret)
1391 return ret;
1392 filled = 1;
1393 }
1394
1395 offset += filled;
1396 size -= filled;
1397 }
1398
1399 return ret;
1400 }
1401
1402 static int vfio_cap_init(struct vfio_pci_device *vdev)
1403 {
1404 struct pci_dev *pdev = vdev->pdev;
1405 u8 *map = vdev->pci_config_map;
1406 u16 status;
1407 u8 pos, *prev, cap;
1408 int loops, ret, caps = 0;
1409
1410 /* Any capabilities? */
1411 ret = pci_read_config_word(pdev, PCI_STATUS, &status);
1412 if (ret)
1413 return ret;
1414
1415 if (!(status & PCI_STATUS_CAP_LIST))
1416 return 0; /* Done */
1417
1418 ret = pci_read_config_byte(pdev, PCI_CAPABILITY_LIST, &pos);
1419 if (ret)
1420 return ret;
1421
1422 /* Mark the previous position in case we want to skip a capability */
1423 prev = &vdev->vconfig[PCI_CAPABILITY_LIST];
1424
1425 /* We can bound our loop, capabilities are dword aligned */
1426 loops = (PCI_CFG_SPACE_SIZE - PCI_STD_HEADER_SIZEOF) / PCI_CAP_SIZEOF;
1427 while (pos && loops--) {
1428 u8 next;
1429 int i, len = 0;
1430
1431 ret = pci_read_config_byte(pdev, pos, &cap);
1432 if (ret)
1433 return ret;
1434
1435 ret = pci_read_config_byte(pdev,
1436 pos + PCI_CAP_LIST_NEXT, &next);
1437 if (ret)
1438 return ret;
1439
1440 if (cap <= PCI_CAP_ID_MAX) {
1441 len = pci_cap_length[cap];
1442 if (len == 0xFF) { /* Variable length */
1443 len = vfio_cap_len(vdev, cap, pos);
1444 if (len < 0)
1445 return len;
1446 }
1447 }
1448
1449 if (!len) {
1450 pr_info("%s: %s hiding cap 0x%x\n",
1451 __func__, dev_name(&pdev->dev), cap);
1452 *prev = next;
1453 pos = next;
1454 continue;
1455 }
1456
1457 /* Sanity check, do we overlap other capabilities? */
1458 for (i = 0; i < len; i++) {
1459 if (likely(map[pos + i] == PCI_CAP_ID_INVALID))
1460 continue;
1461
1462 pr_warn("%s: %s pci config conflict @0x%x, was cap 0x%x now cap 0x%x\n",
1463 __func__, dev_name(&pdev->dev),
1464 pos + i, map[pos + i], cap);
1465 }
1466
1467 BUILD_BUG_ON(PCI_CAP_ID_MAX >= PCI_CAP_ID_INVALID_VIRT);
1468
1469 memset(map + pos, cap, len);
1470 ret = vfio_fill_vconfig_bytes(vdev, pos, len);
1471 if (ret)
1472 return ret;
1473
1474 prev = &vdev->vconfig[pos + PCI_CAP_LIST_NEXT];
1475 pos = next;
1476 caps++;
1477 }
1478
1479 /* If we didn't fill any capabilities, clear the status flag */
1480 if (!caps) {
1481 __le16 *vstatus = (__le16 *)&vdev->vconfig[PCI_STATUS];
1482 *vstatus &= ~cpu_to_le16(PCI_STATUS_CAP_LIST);
1483 }
1484
1485 return 0;
1486 }
1487
1488 static int vfio_ecap_init(struct vfio_pci_device *vdev)
1489 {
1490 struct pci_dev *pdev = vdev->pdev;
1491 u8 *map = vdev->pci_config_map;
1492 u16 epos;
1493 __le32 *prev = NULL;
1494 int loops, ret, ecaps = 0;
1495
1496 if (!vdev->extended_caps)
1497 return 0;
1498
1499 epos = PCI_CFG_SPACE_SIZE;
1500
1501 loops = (pdev->cfg_size - PCI_CFG_SPACE_SIZE) / PCI_CAP_SIZEOF;
1502
1503 while (loops-- && epos >= PCI_CFG_SPACE_SIZE) {
1504 u32 header;
1505 u16 ecap;
1506 int i, len = 0;
1507 bool hidden = false;
1508
1509 ret = pci_read_config_dword(pdev, epos, &header);
1510 if (ret)
1511 return ret;
1512
1513 ecap = PCI_EXT_CAP_ID(header);
1514
1515 if (ecap <= PCI_EXT_CAP_ID_MAX) {
1516 len = pci_ext_cap_length[ecap];
1517 if (len == 0xFF) {
1518 len = vfio_ext_cap_len(vdev, ecap, epos);
1519 if (len < 0)
1520 return ret;
1521 }
1522 }
1523
1524 if (!len) {
1525 pr_info("%s: %s hiding ecap 0x%x@0x%x\n",
1526 __func__, dev_name(&pdev->dev), ecap, epos);
1527
1528 /* If not the first in the chain, we can skip over it */
1529 if (prev) {
1530 u32 val = epos = PCI_EXT_CAP_NEXT(header);
1531 *prev &= cpu_to_le32(~(0xffcU << 20));
1532 *prev |= cpu_to_le32(val << 20);
1533 continue;
1534 }
1535
1536 /*
1537 * Otherwise, fill in a placeholder, the direct
1538 * readfn will virtualize this automatically
1539 */
1540 len = PCI_CAP_SIZEOF;
1541 hidden = true;
1542 }
1543
1544 for (i = 0; i < len; i++) {
1545 if (likely(map[epos + i] == PCI_CAP_ID_INVALID))
1546 continue;
1547
1548 pr_warn("%s: %s pci config conflict @0x%x, was ecap 0x%x now ecap 0x%x\n",
1549 __func__, dev_name(&pdev->dev),
1550 epos + i, map[epos + i], ecap);
1551 }
1552
1553 /*
1554 * Even though ecap is 2 bytes, we're currently a long way
1555 * from exceeding 1 byte capabilities. If we ever make it
1556 * up to 0xFE we'll need to up this to a two-byte, byte map.
1557 */
1558 BUILD_BUG_ON(PCI_EXT_CAP_ID_MAX >= PCI_CAP_ID_INVALID_VIRT);
1559
1560 memset(map + epos, ecap, len);
1561 ret = vfio_fill_vconfig_bytes(vdev, epos, len);
1562 if (ret)
1563 return ret;
1564
1565 /*
1566 * If we're just using this capability to anchor the list,
1567 * hide the real ID. Only count real ecaps. XXX PCI spec
1568 * indicates to use cap id = 0, version = 0, next = 0 if
1569 * ecaps are absent, hope users check all the way to next.
1570 */
1571 if (hidden)
1572 *(__le32 *)&vdev->vconfig[epos] &=
1573 cpu_to_le32((0xffcU << 20));
1574 else
1575 ecaps++;
1576
1577 prev = (__le32 *)&vdev->vconfig[epos];
1578 epos = PCI_EXT_CAP_NEXT(header);
1579 }
1580
1581 if (!ecaps)
1582 *(u32 *)&vdev->vconfig[PCI_CFG_SPACE_SIZE] = 0;
1583
1584 return 0;
1585 }
1586
1587 /*
1588 * For each device we allocate a pci_config_map that indicates the
1589 * capability occupying each dword and thus the struct perm_bits we
1590 * use for read and write. We also allocate a virtualized config
1591 * space which tracks reads and writes to bits that we emulate for
1592 * the user. Initial values filled from device.
1593 *
1594 * Using shared struct perm_bits between all vfio-pci devices saves
1595 * us from allocating cfg_size buffers for virt and write for every
1596 * device. We could remove vconfig and allocate individual buffers
1597 * for each area requiring emulated bits, but the array of pointers
1598 * would be comparable in size (at least for standard config space).
1599 */
1600 int vfio_config_init(struct vfio_pci_device *vdev)
1601 {
1602 struct pci_dev *pdev = vdev->pdev;
1603 u8 *map, *vconfig;
1604 int ret;
1605
1606 /*
1607 * Config space, caps and ecaps are all dword aligned, so we could
1608 * use one byte per dword to record the type. However, there are
1609 * no requiremenst on the length of a capability, so the gap between
1610 * capabilities needs byte granularity.
1611 */
1612 map = kmalloc(pdev->cfg_size, GFP_KERNEL);
1613 if (!map)
1614 return -ENOMEM;
1615
1616 vconfig = kmalloc(pdev->cfg_size, GFP_KERNEL);
1617 if (!vconfig) {
1618 kfree(map);
1619 return -ENOMEM;
1620 }
1621
1622 vdev->pci_config_map = map;
1623 vdev->vconfig = vconfig;
1624
1625 memset(map, PCI_CAP_ID_BASIC, PCI_STD_HEADER_SIZEOF);
1626 memset(map + PCI_STD_HEADER_SIZEOF, PCI_CAP_ID_INVALID,
1627 pdev->cfg_size - PCI_STD_HEADER_SIZEOF);
1628
1629 ret = vfio_fill_vconfig_bytes(vdev, 0, PCI_STD_HEADER_SIZEOF);
1630 if (ret)
1631 goto out;
1632
1633 vdev->bardirty = true;
1634
1635 /*
1636 * XXX can we just pci_load_saved_state/pci_restore_state?
1637 * may need to rebuild vconfig after that
1638 */
1639
1640 /* For restore after reset */
1641 vdev->rbar[0] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_0]);
1642 vdev->rbar[1] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_1]);
1643 vdev->rbar[2] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_2]);
1644 vdev->rbar[3] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_3]);
1645 vdev->rbar[4] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_4]);
1646 vdev->rbar[5] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_5]);
1647 vdev->rbar[6] = le32_to_cpu(*(__le32 *)&vconfig[PCI_ROM_ADDRESS]);
1648
1649 if (pdev->is_virtfn) {
1650 *(__le16 *)&vconfig[PCI_VENDOR_ID] = cpu_to_le16(pdev->vendor);
1651 *(__le16 *)&vconfig[PCI_DEVICE_ID] = cpu_to_le16(pdev->device);
1652 }
1653
1654 if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) || vdev->nointx)
1655 vconfig[PCI_INTERRUPT_PIN] = 0;
1656
1657 ret = vfio_cap_init(vdev);
1658 if (ret)
1659 goto out;
1660
1661 ret = vfio_ecap_init(vdev);
1662 if (ret)
1663 goto out;
1664
1665 return 0;
1666
1667 out:
1668 kfree(map);
1669 vdev->pci_config_map = NULL;
1670 kfree(vconfig);
1671 vdev->vconfig = NULL;
1672 return pcibios_err_to_errno(ret);
1673 }
1674
1675 void vfio_config_free(struct vfio_pci_device *vdev)
1676 {
1677 kfree(vdev->vconfig);
1678 vdev->vconfig = NULL;
1679 kfree(vdev->pci_config_map);
1680 vdev->pci_config_map = NULL;
1681 kfree(vdev->msi_perm);
1682 vdev->msi_perm = NULL;
1683 }
1684
1685 /*
1686 * Find the remaining number of bytes in a dword that match the given
1687 * position. Stop at either the end of the capability or the dword boundary.
1688 */
1689 static size_t vfio_pci_cap_remaining_dword(struct vfio_pci_device *vdev,
1690 loff_t pos)
1691 {
1692 u8 cap = vdev->pci_config_map[pos];
1693 size_t i;
1694
1695 for (i = 1; (pos + i) % 4 && vdev->pci_config_map[pos + i] == cap; i++)
1696 /* nop */;
1697
1698 return i;
1699 }
1700
1701 static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
1702 size_t count, loff_t *ppos, bool iswrite)
1703 {
1704 struct pci_dev *pdev = vdev->pdev;
1705 struct perm_bits *perm;
1706 __le32 val = 0;
1707 int cap_start = 0, offset;
1708 u8 cap_id;
1709 ssize_t ret;
1710
1711 if (*ppos < 0 || *ppos >= pdev->cfg_size ||
1712 *ppos + count > pdev->cfg_size)
1713 return -EFAULT;
1714
1715 /*
1716 * Chop accesses into aligned chunks containing no more than a
1717 * single capability. Caller increments to the next chunk.
1718 */
1719 count = min(count, vfio_pci_cap_remaining_dword(vdev, *ppos));
1720 if (count >= 4 && !(*ppos % 4))
1721 count = 4;
1722 else if (count >= 2 && !(*ppos % 2))
1723 count = 2;
1724 else
1725 count = 1;
1726
1727 ret = count;
1728
1729 cap_id = vdev->pci_config_map[*ppos];
1730
1731 if (cap_id == PCI_CAP_ID_INVALID) {
1732 perm = &unassigned_perms;
1733 cap_start = *ppos;
1734 } else if (cap_id == PCI_CAP_ID_INVALID_VIRT) {
1735 perm = &virt_perms;
1736 cap_start = *ppos;
1737 } else {
1738 if (*ppos >= PCI_CFG_SPACE_SIZE) {
1739 WARN_ON(cap_id > PCI_EXT_CAP_ID_MAX);
1740
1741 perm = &ecap_perms[cap_id];
1742 cap_start = vfio_find_cap_start(vdev, *ppos);
1743 } else {
1744 WARN_ON(cap_id > PCI_CAP_ID_MAX);
1745
1746 perm = &cap_perms[cap_id];
1747
1748 if (cap_id == PCI_CAP_ID_MSI)
1749 perm = vdev->msi_perm;
1750
1751 if (cap_id > PCI_CAP_ID_BASIC)
1752 cap_start = vfio_find_cap_start(vdev, *ppos);
1753 }
1754 }
1755
1756 WARN_ON(!cap_start && cap_id != PCI_CAP_ID_BASIC);
1757 WARN_ON(cap_start > *ppos);
1758
1759 offset = *ppos - cap_start;
1760
1761 if (iswrite) {
1762 if (!perm->writefn)
1763 return ret;
1764
1765 if (copy_from_user(&val, buf, count))
1766 return -EFAULT;
1767
1768 ret = perm->writefn(vdev, *ppos, count, perm, offset, val);
1769 } else {
1770 if (perm->readfn) {
1771 ret = perm->readfn(vdev, *ppos, count,
1772 perm, offset, &val);
1773 if (ret < 0)
1774 return ret;
1775 }
1776
1777 if (copy_to_user(buf, &val, count))
1778 return -EFAULT;
1779 }
1780
1781 return ret;
1782 }
1783
1784 ssize_t vfio_pci_config_rw(struct vfio_pci_device *vdev, char __user *buf,
1785 size_t count, loff_t *ppos, bool iswrite)
1786 {
1787 size_t done = 0;
1788 int ret = 0;
1789 loff_t pos = *ppos;
1790
1791 pos &= VFIO_PCI_OFFSET_MASK;
1792
1793 while (count) {
1794 ret = vfio_config_do_rw(vdev, buf, count, &pos, iswrite);
1795 if (ret < 0)
1796 return ret;
1797
1798 count -= ret;
1799 done += ret;
1800 buf += ret;
1801 pos += ret;
1802 }
1803
1804 *ppos += done;
1805
1806 return done;
1807 }
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