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/pci.h>
15 #include "conf_space.h"
16 #include "conf_space_quirks.h"
18 static int permissive;
19 module_param(permissive, bool, 0644);
21 /* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,
22 * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */
23 #define DEFINE_PCI_CONFIG(op, size, type) \
24 int xen_pcibk_##op##_config_##size \
25 (struct pci_dev *dev, int offset, type value, void *data) \
27 return pci_##op##_config_##size(dev, offset, value); \
30 DEFINE_PCI_CONFIG(read, byte, u8 *)
31 DEFINE_PCI_CONFIG(read, word, u16 *)
32 DEFINE_PCI_CONFIG(read, dword, u32 *)
34 DEFINE_PCI_CONFIG(write, byte, u8)
35 DEFINE_PCI_CONFIG(write, word, u16)
36 DEFINE_PCI_CONFIG(write, dword, u32)
38 static int conf_space_read(struct pci_dev *dev,
39 const struct config_field_entry *entry,
40 int offset, u32 *value)
43 const struct config_field *field = entry->field;
47 switch (field->size) {
50 ret = field->u.b.read(dev, offset, (u8 *) value,
55 ret = field->u.w.read(dev, offset, (u16 *) value,
60 ret = field->u.dw.read(dev, offset, value, entry->data);
66 static int conf_space_write(struct pci_dev *dev,
67 const struct config_field_entry *entry,
68 int offset, u32 value)
71 const struct config_field *field = entry->field;
73 switch (field->size) {
76 ret = field->u.b.write(dev, offset, (u8) value,
81 ret = field->u.w.write(dev, offset, (u16) value,
85 if (field->u.dw.write)
86 ret = field->u.dw.write(dev, offset, value,
93 static inline u32 get_mask(int size)
103 static inline int valid_request(int offset, int size)
105 /* Validate request (no un-aligned requests) */
106 if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
111 static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
115 new_val_mask <<= (offset * 8);
116 new_val <<= (offset * 8);
118 new_val_mask >>= (offset * -8);
119 new_val >>= (offset * -8);
121 val = (val & ~new_val_mask) | (new_val & new_val_mask);
126 static int pcibios_err_to_errno(int err)
129 case PCIBIOS_SUCCESSFUL:
130 return XEN_PCI_ERR_success;
131 case PCIBIOS_DEVICE_NOT_FOUND:
132 return XEN_PCI_ERR_dev_not_found;
133 case PCIBIOS_BAD_REGISTER_NUMBER:
134 return XEN_PCI_ERR_invalid_offset;
135 case PCIBIOS_FUNC_NOT_SUPPORTED:
136 return XEN_PCI_ERR_not_implemented;
137 case PCIBIOS_SET_FAILED:
138 return XEN_PCI_ERR_access_denied;
143 int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
147 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
148 const struct config_field_entry *cfg_entry;
149 const struct config_field *field;
150 int req_start, req_end, field_start, field_end;
151 /* if read fails for any reason, return 0
152 * (as if device didn't respond) */
153 u32 value = 0, tmp_val;
155 if (unlikely(verbose_request))
156 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n",
157 pci_name(dev), size, offset);
159 if (!valid_request(offset, size)) {
160 err = XEN_PCI_ERR_invalid_offset;
164 /* Get the real value first, then modify as appropriate */
167 err = pci_read_config_byte(dev, offset, (u8 *) &value);
170 err = pci_read_config_word(dev, offset, (u16 *) &value);
173 err = pci_read_config_dword(dev, offset, &value);
177 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
178 field = cfg_entry->field;
181 req_end = offset + size;
182 field_start = OFFSET(cfg_entry);
183 field_end = OFFSET(cfg_entry) + field->size;
185 if ((req_start >= field_start && req_start < field_end)
186 || (req_end > field_start && req_end <= field_end)) {
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 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_start >= field_start && req_start < field_end)
233 || (req_end > field_start && req_end <= field_end)) {
236 err = xen_pcibk_config_read(dev, field_start,
237 field->size, &tmp_val);
241 tmp_val = merge_value(tmp_val, value, get_mask(size),
242 req_start - field_start);
244 err = conf_space_write(dev, cfg_entry, field_start,
247 /* handled is set true here, but not every byte
248 * may have been written! Properly detecting if
249 * every byte is handled is unnecessary as the
250 * flag is used to detect devices that need
251 * special helpers to work correctly.
257 if (!handled && !err) {
258 /* By default, anything not specificially handled above is
259 * read-only. The permissive flag changes this behavior so
260 * that anything not specifically handled above is writable.
261 * This means that some fields may still be read-only because
262 * they have entries in the config_field list that intercept
263 * the write and do nothing. */
264 if (dev_data->permissive || permissive) {
267 err = pci_write_config_byte(dev, offset,
271 err = pci_write_config_word(dev, offset,
275 err = pci_write_config_dword(dev, offset,
279 } else if (!dev_data->warned_on_write) {
280 dev_data->warned_on_write = 1;
281 dev_warn(&dev->dev, "Driver tried to write to a "
282 "read-only configuration space field at offset"
283 " 0x%x, size %d. This may be harmless, but if "
284 "you have problems with your device:\n"
285 "1) see permissive attribute in sysfs\n"
286 "2) report problems to the xen-devel "
287 "mailing list along with details of your "
288 "device obtained from lspci.\n", offset, size);
292 return pcibios_err_to_errno(err);
295 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
297 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
298 struct config_field_entry *cfg_entry, *t;
299 const struct config_field *field;
301 dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
302 "configuration space fields\n");
306 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
307 field = cfg_entry->field;
310 field->clean((struct config_field *)field);
312 kfree(cfg_entry->data);
314 list_del(&cfg_entry->list);
321 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
323 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
324 const struct config_field_entry *cfg_entry;
325 const struct config_field *field;
327 dev_dbg(&dev->dev, "resetting virtual configuration space\n");
331 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
332 field = cfg_entry->field;
335 field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
339 void xen_pcibk_config_free_dev(struct pci_dev *dev)
341 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
342 struct config_field_entry *cfg_entry, *t;
343 const struct config_field *field;
345 dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
349 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
350 list_del(&cfg_entry->list);
352 field = cfg_entry->field;
355 field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
361 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
362 const struct config_field *field,
363 unsigned int base_offset)
366 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
367 struct config_field_entry *cfg_entry;
370 cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
376 cfg_entry->data = NULL;
377 cfg_entry->field = field;
378 cfg_entry->base_offset = base_offset;
380 /* silently ignore duplicate fields */
381 err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
386 tmp = field->init(dev, OFFSET(cfg_entry));
393 cfg_entry->data = tmp;
396 dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
398 list_add_tail(&cfg_entry->list, &dev_data->config_fields);
407 /* This sets up the device's virtual configuration space to keep track of
408 * certain registers (like the base address registers (BARs) so that we can
409 * keep the client from manipulating them directly.
411 int xen_pcibk_config_init_dev(struct pci_dev *dev)
414 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
416 dev_dbg(&dev->dev, "initializing virtual configuration space\n");
418 INIT_LIST_HEAD(&dev_data->config_fields);
420 err = xen_pcibk_config_header_add_fields(dev);
424 err = xen_pcibk_config_capability_add_fields(dev);
428 err = xen_pcibk_config_quirks_init(dev);
434 int xen_pcibk_config_init(void)
436 return xen_pcibk_config_capability_init();