drivers/xen/pciback/conf_space.c

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