drivers/xen/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/moduleparam.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
  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
  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
  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
 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
 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
 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
 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 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                 field_start = OFFSET(cfg_entry);
 182                 field_end = OFFSET(cfg_entry) + field->size;
 183
 184                 if (offset + size > field_start && field_end > offset) {
 185                         err = conf_space_read(dev, cfg_entry, field_start,
 186                                               &tmp_val);
 187                         if (err)
 188                                 goto out;
 189
 190                         value = merge_value(value, tmp_val,
 191                                             get_mask(field->size),
 192                                             field_start - offset);
 193                 }
 194         }
 195
 196 out:
 197         if (unlikely(verbose_request))
 198                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
 199                        pci_name(dev), size, offset, value);
 200
 201         *ret_val = value;
 202         return xen_pcibios_err_to_errno(err);
 203 }
 204
 205 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
 206 {
 207         int err = 0, handled = 0;
 208         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 209         const struct config_field_entry *cfg_entry;
 210         const struct config_field *field;
 211         u32 tmp_val;
 212         int field_start, field_end;
 213
 214         if (unlikely(verbose_request))
 215                 printk(KERN_DEBUG
 216                        DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
 217                        pci_name(dev), size, offset, value);
 218
 219         if (!valid_request(offset, size))
 220                 return XEN_PCI_ERR_invalid_offset;
 221
 222         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 223                 field = cfg_entry->field;
 224
 225                 field_start = OFFSET(cfg_entry);
 226                 field_end = OFFSET(cfg_entry) + field->size;
 227
 228                 if (offset + size > field_start && field_end > offset) {
 229                         err = conf_space_read(dev, cfg_entry, field_start,
 230                                               &tmp_val);
 231                         if (err)
 232                                 break;
 233
 234                         tmp_val = merge_value(tmp_val, value, get_mask(size),
 235                                               offset - field_start);
 236
 237                         err = conf_space_write(dev, cfg_entry, field_start,
 238                                                tmp_val);
 239
 240                         /* handled is set true here, but not every byte
 241                          * may have been written! Properly detecting if
 242                          * every byte is handled is unnecessary as the
 243                          * flag is used to detect devices that need
 244                          * special helpers to work correctly.
 245                          */
 246                         handled = 1;
 247                 }
 248         }
 249
 250         if (!handled && !err) {
 251                 /* By default, anything not specificially handled above is
 252                  * read-only. The permissive flag changes this behavior so
 253                  * that anything not specifically handled above is writable.
 254                  * This means that some fields may still be read-only because
 255                  * they have entries in the config_field list that intercept
 256                  * the write and do nothing. */
 257                 if (dev_data->permissive || xen_pcibk_permissive) {
 258                         switch (size) {
 259                         case 1:
 260                                 err = pci_write_config_byte(dev, offset,
 261                                                             (u8) value);
 262                                 break;
 263                         case 2:
 264                                 err = pci_write_config_word(dev, offset,
 265                                                             (u16) value);
 266                                 break;
 267                         case 4:
 268                                 err = pci_write_config_dword(dev, offset,
 269                                                              (u32) value);
 270                                 break;
 271                         }
 272                 } else if (!dev_data->warned_on_write) {
 273                         dev_data->warned_on_write = 1;
 274                         dev_warn(&dev->dev, "Driver tried to write to a "
 275                                  "read-only configuration space field at offset"
 276                                  " 0x%x, size %d. This may be harmless, but if "
 277                                  "you have problems with your device:\n"
 278                                  "1) see permissive attribute in sysfs\n"
 279                                  "2) report problems to the xen-devel "
 280                                  "mailing list along with details of your "
 281                                  "device obtained from lspci.\n", offset, size);
 282                 }
 283         }
 284
 285         return xen_pcibios_err_to_errno(err);
 286 }
 287
 288 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
 289 {
 290         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 291         struct config_field_entry *cfg_entry, *t;
 292         const struct config_field *field;
 293
 294         dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
 295                            "configuration space fields\n");
 296         if (!dev_data)
 297                 return;
 298
 299         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 300                 field = cfg_entry->field;
 301
 302                 if (field->clean) {
 303                         field->clean((struct config_field *)field);
 304
 305                         kfree(cfg_entry->data);
 306
 307                         list_del(&cfg_entry->list);
 308                         kfree(cfg_entry);
 309                 }
 310
 311         }
 312 }
 313
 314 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
 315 {
 316         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 317         const struct config_field_entry *cfg_entry;
 318         const struct config_field *field;
 319
 320         dev_dbg(&dev->dev, "resetting virtual configuration space\n");
 321         if (!dev_data)
 322                 return;
 323
 324         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 325                 field = cfg_entry->field;
 326
 327                 if (field->reset)
 328                         field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
 329         }
 330 }
 331
 332 void xen_pcibk_config_free_dev(struct pci_dev *dev)
 333 {
 334         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 335         struct config_field_entry *cfg_entry, *t;
 336         const struct config_field *field;
 337
 338         dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
 339         if (!dev_data)
 340                 return;
 341
 342         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 343                 list_del(&cfg_entry->list);
 344
 345                 field = cfg_entry->field;
 346
 347                 if (field->release)
 348                         field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
 349
 350                 kfree(cfg_entry);
 351         }
 352 }
 353
 354 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
 355                                     const struct config_field *field,
 356                                     unsigned int base_offset)
 357 {
 358         int err = 0;
 359         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 360         struct config_field_entry *cfg_entry;
 361         void *tmp;
 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 = base_offset;
 372
 373         /* silently ignore duplicate fields */
 374         err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
 375         if (err)
 376                 goto out;
 377
 378         if (field->init) {
 379                 tmp = field->init(dev, OFFSET(cfg_entry));
 380
 381                 if (IS_ERR(tmp)) {
 382                         err = PTR_ERR(tmp);
 383                         goto out;
 384                 }
 385
 386                 cfg_entry->data = tmp;
 387         }
 388
 389         dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
 390                 OFFSET(cfg_entry));
 391         list_add_tail(&cfg_entry->list, &dev_data->config_fields);
 392
 393 out:
 394         if (err)
 395                 kfree(cfg_entry);
 396
 397         return err;
 398 }
 399
 400 /* This sets up the device's virtual configuration space to keep track of
 401  * certain registers (like the base address registers (BARs) so that we can
 402  * keep the client from manipulating them directly.
 403  */
 404 int xen_pcibk_config_init_dev(struct pci_dev *dev)
 405 {
 406         int err = 0;
 407         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 408
 409         dev_dbg(&dev->dev, "initializing virtual configuration space\n");
 410
 411         INIT_LIST_HEAD(&dev_data->config_fields);
 412
 413         err = xen_pcibk_config_header_add_fields(dev);
 414         if (err)
 415                 goto out;
 416
 417         err = xen_pcibk_config_capability_add_fields(dev);
 418         if (err)
 419                 goto out;
 420
 421         err = xen_pcibk_config_quirks_init(dev);
 422
 423 out:
 424         return err;
 425 }
 426
 427 int xen_pcibk_config_init(void)
 428 {
 429         return xen_pcibk_config_capability_init();
 430 }