1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * PCI Backend - Functions for creating a virtual configuration space for |
4 | * exported PCI Devices. |
5 | * It's dangerous to allow PCI Driver Domains to change their |
6 | * device's resources (memory, i/o ports, interrupts). We need to |
7 | * restrict changes to certain PCI Configuration registers: |
8 | * BARs, INTERRUPT_PIN, most registers in the header... |
9 | * |
10 | * Author: Ryan Wilson <hap9@epoch.ncsc.mil> |
11 | */ |
12 | |
13 | #define dev_fmt(fmt) DRV_NAME ": " fmt |
14 | |
15 | #include <linux/kernel.h> |
16 | #include <linux/moduleparam.h> |
17 | #include <linux/pci.h> |
18 | #include "pciback.h" |
19 | #include "conf_space.h" |
20 | #include "conf_space_quirks.h" |
21 | |
22 | bool xen_pcibk_permissive; |
23 | module_param_named(permissive, xen_pcibk_permissive, bool, 0644); |
24 | |
25 | /* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word, |
26 | * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */ |
27 | #define DEFINE_PCI_CONFIG(op, size, type) \ |
28 | int xen_pcibk_##op##_config_##size \ |
29 | (struct pci_dev *dev, int offset, type value, void *data) \ |
30 | { \ |
31 | return pci_##op##_config_##size(dev, offset, value); \ |
32 | } |
33 | |
34 | DEFINE_PCI_CONFIG(read, byte, u8 *) |
35 | DEFINE_PCI_CONFIG(read, word, u16 *) |
36 | DEFINE_PCI_CONFIG(read, dword, u32 *) |
37 | |
38 | DEFINE_PCI_CONFIG(write, byte, u8) |
39 | DEFINE_PCI_CONFIG(write, word, u16) |
40 | DEFINE_PCI_CONFIG(write, dword, u32) |
41 | |
42 | static int conf_space_read(struct pci_dev *dev, |
43 | const struct config_field_entry *entry, |
44 | int offset, u32 *value) |
45 | { |
46 | int ret = 0; |
47 | const struct config_field *field = entry->field; |
48 | |
49 | *value = 0; |
50 | |
51 | switch (field->size) { |
52 | case 1: |
53 | if (field->u.b.read) |
54 | ret = field->u.b.read(dev, offset, (u8 *) value, |
55 | entry->data); |
56 | break; |
57 | case 2: |
58 | if (field->u.w.read) |
59 | ret = field->u.w.read(dev, offset, (u16 *) value, |
60 | entry->data); |
61 | break; |
62 | case 4: |
63 | if (field->u.dw.read) |
64 | ret = field->u.dw.read(dev, offset, value, entry->data); |
65 | break; |
66 | } |
67 | return ret; |
68 | } |
69 | |
70 | static int conf_space_write(struct pci_dev *dev, |
71 | const struct config_field_entry *entry, |
72 | int offset, u32 value) |
73 | { |
74 | int ret = 0; |
75 | const struct config_field *field = entry->field; |
76 | |
77 | switch (field->size) { |
78 | case 1: |
79 | if (field->u.b.write) |
80 | ret = field->u.b.write(dev, offset, (u8) value, |
81 | entry->data); |
82 | break; |
83 | case 2: |
84 | if (field->u.w.write) |
85 | ret = field->u.w.write(dev, offset, (u16) value, |
86 | entry->data); |
87 | break; |
88 | case 4: |
89 | if (field->u.dw.write) |
90 | ret = field->u.dw.write(dev, offset, value, |
91 | entry->data); |
92 | break; |
93 | } |
94 | return ret; |
95 | } |
96 | |
97 | static inline u32 get_mask(int size) |
98 | { |
99 | if (size == 1) |
100 | return 0xff; |
101 | else if (size == 2) |
102 | return 0xffff; |
103 | else |
104 | return 0xffffffff; |
105 | } |
106 | |
107 | static inline int valid_request(int offset, int size) |
108 | { |
109 | /* Validate request (no un-aligned requests) */ |
110 | if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0) |
111 | return 1; |
112 | return 0; |
113 | } |
114 | |
115 | static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask, |
116 | int offset) |
117 | { |
118 | if (offset >= 0) { |
119 | new_val_mask <<= (offset * 8); |
120 | new_val <<= (offset * 8); |
121 | } else { |
122 | new_val_mask >>= (offset * -8); |
123 | new_val >>= (offset * -8); |
124 | } |
125 | val = (val & ~new_val_mask) | (new_val & new_val_mask); |
126 | |
127 | return val; |
128 | } |
129 | |
130 | static int xen_pcibios_err_to_errno(int err) |
131 | { |
132 | switch (err) { |
133 | case PCIBIOS_SUCCESSFUL: |
134 | return XEN_PCI_ERR_success; |
135 | case PCIBIOS_DEVICE_NOT_FOUND: |
136 | return XEN_PCI_ERR_dev_not_found; |
137 | case PCIBIOS_BAD_REGISTER_NUMBER: |
138 | return XEN_PCI_ERR_invalid_offset; |
139 | case PCIBIOS_FUNC_NOT_SUPPORTED: |
140 | return XEN_PCI_ERR_not_implemented; |
141 | case PCIBIOS_SET_FAILED: |
142 | return XEN_PCI_ERR_access_denied; |
143 | } |
144 | return err; |
145 | } |
146 | |
147 | int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size, |
148 | u32 *ret_val) |
149 | { |
150 | int err = 0; |
151 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
152 | const struct config_field_entry *cfg_entry; |
153 | const struct config_field *field; |
154 | int field_start, field_end; |
155 | /* if read fails for any reason, return 0 |
156 | * (as if device didn't respond) */ |
157 | u32 value = 0, tmp_val; |
158 | |
159 | dev_dbg(&dev->dev, "read %d bytes at 0x%x\n" , size, offset); |
160 | |
161 | if (!valid_request(offset, size)) { |
162 | err = XEN_PCI_ERR_invalid_offset; |
163 | goto out; |
164 | } |
165 | |
166 | /* Get the real value first, then modify as appropriate */ |
167 | switch (size) { |
168 | case 1: |
169 | err = pci_read_config_byte(dev, where: offset, val: (u8 *) &value); |
170 | break; |
171 | case 2: |
172 | err = pci_read_config_word(dev, where: offset, val: (u16 *) &value); |
173 | break; |
174 | case 4: |
175 | err = pci_read_config_dword(dev, where: offset, val: &value); |
176 | break; |
177 | } |
178 | |
179 | list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { |
180 | field = cfg_entry->field; |
181 | |
182 | field_start = OFFSET(cfg_entry); |
183 | field_end = OFFSET(cfg_entry) + field->size; |
184 | |
185 | if (offset + size > field_start && field_end > offset) { |
186 | err = conf_space_read(dev, entry: cfg_entry, offset: field_start, |
187 | value: &tmp_val); |
188 | if (err) |
189 | goto out; |
190 | |
191 | value = merge_value(val: value, new_val: tmp_val, |
192 | new_val_mask: get_mask(size: field->size), |
193 | offset: field_start - offset); |
194 | } |
195 | } |
196 | |
197 | out: |
198 | dev_dbg(&dev->dev, "read %d bytes at 0x%x = %x\n" , size, offset, value); |
199 | |
200 | *ret_val = value; |
201 | return xen_pcibios_err_to_errno(err); |
202 | } |
203 | |
204 | int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value) |
205 | { |
206 | int err = 0, handled = 0; |
207 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
208 | const struct config_field_entry *cfg_entry; |
209 | const struct config_field *field; |
210 | u32 tmp_val; |
211 | int field_start, field_end; |
212 | |
213 | dev_dbg(&dev->dev, "write request %d bytes at 0x%x = %x\n" , |
214 | size, offset, value); |
215 | |
216 | if (!valid_request(offset, size)) |
217 | return XEN_PCI_ERR_invalid_offset; |
218 | |
219 | list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { |
220 | field = cfg_entry->field; |
221 | |
222 | field_start = OFFSET(cfg_entry); |
223 | field_end = OFFSET(cfg_entry) + field->size; |
224 | |
225 | if (offset + size > field_start && field_end > offset) { |
226 | err = conf_space_read(dev, entry: cfg_entry, offset: field_start, |
227 | value: &tmp_val); |
228 | if (err) |
229 | break; |
230 | |
231 | tmp_val = merge_value(val: tmp_val, new_val: value, new_val_mask: get_mask(size), |
232 | offset: offset - field_start); |
233 | |
234 | err = conf_space_write(dev, entry: cfg_entry, offset: field_start, |
235 | value: tmp_val); |
236 | |
237 | /* handled is set true here, but not every byte |
238 | * may have been written! Properly detecting if |
239 | * every byte is handled is unnecessary as the |
240 | * flag is used to detect devices that need |
241 | * special helpers to work correctly. |
242 | */ |
243 | handled = 1; |
244 | } |
245 | } |
246 | |
247 | if (!handled && !err) { |
248 | /* By default, anything not specificially handled above is |
249 | * read-only. The permissive flag changes this behavior so |
250 | * that anything not specifically handled above is writable. |
251 | * This means that some fields may still be read-only because |
252 | * they have entries in the config_field list that intercept |
253 | * the write and do nothing. */ |
254 | if (dev_data->permissive || xen_pcibk_permissive) { |
255 | switch (size) { |
256 | case 1: |
257 | err = pci_write_config_byte(dev, where: offset, |
258 | val: (u8) value); |
259 | break; |
260 | case 2: |
261 | err = pci_write_config_word(dev, where: offset, |
262 | val: (u16) value); |
263 | break; |
264 | case 4: |
265 | err = pci_write_config_dword(dev, where: offset, |
266 | val: (u32) value); |
267 | break; |
268 | } |
269 | } else if (!dev_data->warned_on_write) { |
270 | dev_data->warned_on_write = 1; |
271 | dev_warn(&dev->dev, "Driver tried to write to a " |
272 | "read-only configuration space field at offset" |
273 | " 0x%x, size %d. This may be harmless, but if " |
274 | "you have problems with your device:\n" |
275 | "1) see permissive attribute in sysfs\n" |
276 | "2) report problems to the xen-devel " |
277 | "mailing list along with details of your " |
278 | "device obtained from lspci.\n" , offset, size); |
279 | } |
280 | } |
281 | |
282 | return xen_pcibios_err_to_errno(err); |
283 | } |
284 | |
285 | int xen_pcibk_get_interrupt_type(struct pci_dev *dev) |
286 | { |
287 | int err; |
288 | u16 val; |
289 | int ret = 0; |
290 | |
291 | /* |
292 | * Do not trust dev->msi(x)_enabled here, as enabling could be done |
293 | * bypassing the pci_*msi* functions, by the qemu. |
294 | */ |
295 | if (dev->msi_cap) { |
296 | err = pci_read_config_word(dev, |
297 | where: dev->msi_cap + PCI_MSI_FLAGS, |
298 | val: &val); |
299 | if (err) |
300 | return err; |
301 | if (val & PCI_MSI_FLAGS_ENABLE) |
302 | ret |= INTERRUPT_TYPE_MSI; |
303 | } |
304 | if (dev->msix_cap) { |
305 | err = pci_read_config_word(dev, |
306 | where: dev->msix_cap + PCI_MSIX_FLAGS, |
307 | val: &val); |
308 | if (err) |
309 | return err; |
310 | if (val & PCI_MSIX_FLAGS_ENABLE) |
311 | ret |= INTERRUPT_TYPE_MSIX; |
312 | } |
313 | |
314 | /* |
315 | * PCIe spec says device cannot use INTx if MSI/MSI-X is enabled, |
316 | * so check for INTx only when both are disabled. |
317 | */ |
318 | if (!ret) { |
319 | err = pci_read_config_word(dev, PCI_COMMAND, val: &val); |
320 | if (err) |
321 | return err; |
322 | if (!(val & PCI_COMMAND_INTX_DISABLE)) |
323 | ret |= INTERRUPT_TYPE_INTX; |
324 | } |
325 | |
326 | return ret ?: INTERRUPT_TYPE_NONE; |
327 | } |
328 | |
329 | void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev) |
330 | { |
331 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
332 | struct config_field_entry *cfg_entry, *t; |
333 | const struct config_field *field; |
334 | |
335 | dev_dbg(&dev->dev, "free-ing dynamically allocated virtual " |
336 | "configuration space fields\n" ); |
337 | if (!dev_data) |
338 | return; |
339 | |
340 | list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) { |
341 | field = cfg_entry->field; |
342 | |
343 | if (field->clean) { |
344 | field->clean((struct config_field *)field); |
345 | |
346 | kfree(objp: cfg_entry->data); |
347 | |
348 | list_del(entry: &cfg_entry->list); |
349 | kfree(objp: cfg_entry); |
350 | } |
351 | |
352 | } |
353 | } |
354 | |
355 | void xen_pcibk_config_reset_dev(struct pci_dev *dev) |
356 | { |
357 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
358 | const struct config_field_entry *cfg_entry; |
359 | const struct config_field *field; |
360 | |
361 | dev_dbg(&dev->dev, "resetting virtual configuration space\n" ); |
362 | if (!dev_data) |
363 | return; |
364 | |
365 | list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { |
366 | field = cfg_entry->field; |
367 | |
368 | if (field->reset) |
369 | field->reset(dev, OFFSET(cfg_entry), cfg_entry->data); |
370 | } |
371 | } |
372 | |
373 | void xen_pcibk_config_free_dev(struct pci_dev *dev) |
374 | { |
375 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
376 | struct config_field_entry *cfg_entry, *t; |
377 | const struct config_field *field; |
378 | |
379 | dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n" ); |
380 | if (!dev_data) |
381 | return; |
382 | |
383 | list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) { |
384 | list_del(entry: &cfg_entry->list); |
385 | |
386 | field = cfg_entry->field; |
387 | |
388 | if (field->release) |
389 | field->release(dev, OFFSET(cfg_entry), cfg_entry->data); |
390 | |
391 | kfree(objp: cfg_entry); |
392 | } |
393 | } |
394 | |
395 | int xen_pcibk_config_add_field_offset(struct pci_dev *dev, |
396 | const struct config_field *field, |
397 | unsigned int base_offset) |
398 | { |
399 | int err = 0; |
400 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
401 | struct config_field_entry *cfg_entry; |
402 | void *tmp; |
403 | |
404 | cfg_entry = kmalloc(size: sizeof(*cfg_entry), GFP_KERNEL); |
405 | if (!cfg_entry) { |
406 | err = -ENOMEM; |
407 | goto out; |
408 | } |
409 | |
410 | cfg_entry->data = NULL; |
411 | cfg_entry->field = field; |
412 | cfg_entry->base_offset = base_offset; |
413 | |
414 | /* silently ignore duplicate fields */ |
415 | err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry)); |
416 | if (err) |
417 | goto out; |
418 | |
419 | if (field->init) { |
420 | tmp = field->init(dev, OFFSET(cfg_entry)); |
421 | |
422 | if (IS_ERR(ptr: tmp)) { |
423 | err = PTR_ERR(ptr: tmp); |
424 | goto out; |
425 | } |
426 | |
427 | cfg_entry->data = tmp; |
428 | } |
429 | |
430 | dev_dbg(&dev->dev, "added config field at offset 0x%02x\n" , |
431 | OFFSET(cfg_entry)); |
432 | list_add_tail(new: &cfg_entry->list, head: &dev_data->config_fields); |
433 | |
434 | out: |
435 | if (err) |
436 | kfree(objp: cfg_entry); |
437 | |
438 | return err; |
439 | } |
440 | |
441 | /* This sets up the device's virtual configuration space to keep track of |
442 | * certain registers (like the base address registers (BARs) so that we can |
443 | * keep the client from manipulating them directly. |
444 | */ |
445 | int xen_pcibk_config_init_dev(struct pci_dev *dev) |
446 | { |
447 | int err = 0; |
448 | struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pdev: dev); |
449 | |
450 | dev_dbg(&dev->dev, "initializing virtual configuration space\n" ); |
451 | |
452 | INIT_LIST_HEAD(list: &dev_data->config_fields); |
453 | |
454 | err = xen_pcibk_config_header_add_fields(dev); |
455 | if (err) |
456 | goto out; |
457 | |
458 | err = xen_pcibk_config_capability_add_fields(dev); |
459 | if (err) |
460 | goto out; |
461 | |
462 | err = xen_pcibk_config_quirks_init(dev); |
463 | |
464 | out: |
465 | return err; |
466 | } |
467 | |
468 | int xen_pcibk_config_init(void) |
469 | { |
470 | return xen_pcibk_config_capability_init(); |
471 | } |
472 | |