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