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...
9 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
12 #include <linux/kernel.h>
13 #include <linux/moduleparam.h>
14 #include <linux/pci.h>
16 #include "conf_space.h"
17 #include "conf_space_quirks.h"
19 bool xen_pcibk_permissive;
20 module_param_named(permissive, xen_pcibk_permissive, bool, 0644);
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) \
28 return pci_##op##_config_##size(dev, offset, value); \
31 DEFINE_PCI_CONFIG(read, byte, u8 *)
32 DEFINE_PCI_CONFIG(read, word, u16 *)
33 DEFINE_PCI_CONFIG(read, dword, u32 *)
35 DEFINE_PCI_CONFIG(write, byte, u8)
36 DEFINE_PCI_CONFIG(write, word, u16)
37 DEFINE_PCI_CONFIG(write, dword, u32)
39 static int conf_space_read(struct pci_dev *dev,
40 const struct config_field_entry *entry,
41 int offset, u32 *value)
44 const struct config_field *field = entry->field;
48 switch (field->size) {
51 ret = field->u.b.read(dev, offset, (u8 *) value,
56 ret = field->u.w.read(dev, offset, (u16 *) value,
61 ret = field->u.dw.read(dev, offset, value, entry->data);
67 static int conf_space_write(struct pci_dev *dev,
68 const struct config_field_entry *entry,
69 int offset, u32 value)
72 const struct config_field *field = entry->field;
74 switch (field->size) {
77 ret = field->u.b.write(dev, offset, (u8) value,
82 ret = field->u.w.write(dev, offset, (u16) value,
86 if (field->u.dw.write)
87 ret = field->u.dw.write(dev, offset, value,
94 static inline u32 get_mask(int size)
104 static inline int valid_request(int offset, int size)
106 /* Validate request (no un-aligned requests) */
107 if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
112 static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
116 new_val_mask <<= (offset * 8);
117 new_val <<= (offset * 8);
119 new_val_mask >>= (offset * -8);
120 new_val >>= (offset * -8);
122 val = (val & ~new_val_mask) | (new_val & new_val_mask);
127 static int xen_pcibios_err_to_errno(int 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;
144 int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
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;
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);
160 if (!valid_request(offset, size)) {
161 err = XEN_PCI_ERR_invalid_offset;
165 /* Get the real value first, then modify as appropriate */
168 err = pci_read_config_byte(dev, offset, (u8 *) &value);
171 err = pci_read_config_word(dev, offset, (u16 *) &value);
174 err = pci_read_config_dword(dev, offset, &value);
178 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
179 field = cfg_entry->field;
182 req_end = offset + size;
183 field_start = OFFSET(cfg_entry);
184 field_end = OFFSET(cfg_entry) + field->size;
186 if (req_end > field_start && field_end > req_start) {
187 err = conf_space_read(dev, cfg_entry, field_start,
192 value = merge_value(value, tmp_val,
193 get_mask(field->size),
194 field_start - req_start);
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);
204 return xen_pcibios_err_to_errno(err);
207 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
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;
214 int req_start, req_end, field_start, field_end;
216 if (unlikely(verbose_request))
218 DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
219 pci_name(dev), size, offset, value);
221 if (!valid_request(offset, size))
222 return XEN_PCI_ERR_invalid_offset;
224 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
225 field = cfg_entry->field;
228 req_end = offset + size;
229 field_start = OFFSET(cfg_entry);
230 field_end = OFFSET(cfg_entry) + field->size;
232 if (req_end > field_start && field_end > req_start) {
233 err = conf_space_read(dev, cfg_entry, field_start,
238 tmp_val = merge_value(tmp_val, value, get_mask(size),
239 req_start - field_start);
241 err = conf_space_write(dev, cfg_entry, field_start,
244 /* handled is set true here, but not every byte
245 * may have been written! Properly detecting if
246 * every byte is handled is unnecessary as the
247 * flag is used to detect devices that need
248 * special helpers to work correctly.
254 if (!handled && !err) {
255 /* By default, anything not specificially handled above is
256 * read-only. The permissive flag changes this behavior so
257 * that anything not specifically handled above is writable.
258 * This means that some fields may still be read-only because
259 * they have entries in the config_field list that intercept
260 * the write and do nothing. */
261 if (dev_data->permissive || xen_pcibk_permissive) {
264 err = pci_write_config_byte(dev, offset,
268 err = pci_write_config_word(dev, offset,
272 err = pci_write_config_dword(dev, offset,
276 } else if (!dev_data->warned_on_write) {
277 dev_data->warned_on_write = 1;
278 dev_warn(&dev->dev, "Driver tried to write to a "
279 "read-only configuration space field at offset"
280 " 0x%x, size %d. This may be harmless, but if "
281 "you have problems with your device:\n"
282 "1) see permissive attribute in sysfs\n"
283 "2) report problems to the xen-devel "
284 "mailing list along with details of your "
285 "device obtained from lspci.\n", offset, size);
289 return xen_pcibios_err_to_errno(err);
292 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
294 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
295 struct config_field_entry *cfg_entry, *t;
296 const struct config_field *field;
298 dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
299 "configuration space fields\n");
303 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
304 field = cfg_entry->field;
307 field->clean((struct config_field *)field);
309 kfree(cfg_entry->data);
311 list_del(&cfg_entry->list);
318 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
320 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
321 const struct config_field_entry *cfg_entry;
322 const struct config_field *field;
324 dev_dbg(&dev->dev, "resetting virtual configuration space\n");
328 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
329 field = cfg_entry->field;
332 field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
336 void xen_pcibk_config_free_dev(struct pci_dev *dev)
338 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
339 struct config_field_entry *cfg_entry, *t;
340 const struct config_field *field;
342 dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
346 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
347 list_del(&cfg_entry->list);
349 field = cfg_entry->field;
352 field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
358 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
359 const struct config_field *field,
360 unsigned int base_offset)
363 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
364 struct config_field_entry *cfg_entry;
367 cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
373 cfg_entry->data = NULL;
374 cfg_entry->field = field;
375 cfg_entry->base_offset = base_offset;
377 /* silently ignore duplicate fields */
378 err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
383 tmp = field->init(dev, OFFSET(cfg_entry));
390 cfg_entry->data = tmp;
393 dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
395 list_add_tail(&cfg_entry->list, &dev_data->config_fields);
404 /* This sets up the device's virtual configuration space to keep track of
405 * certain registers (like the base address registers (BARs) so that we can
406 * keep the client from manipulating them directly.
408 int xen_pcibk_config_init_dev(struct pci_dev *dev)
411 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
413 dev_dbg(&dev->dev, "initializing virtual configuration space\n");
415 INIT_LIST_HEAD(&dev_data->config_fields);
417 err = xen_pcibk_config_header_add_fields(dev);
421 err = xen_pcibk_config_capability_add_fields(dev);
425 err = xen_pcibk_config_quirks_init(dev);
431 int xen_pcibk_config_init(void)
433 return xen_pcibk_config_capability_init();