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/pci.h>
  14 #include "pciback.h"
  15 #include "conf_space.h"
  16 #include "conf_space_quirks.h"
  17
  18 static int permissive;
  19 module_param(permissive, bool, 0644);
  20
  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)       \
  26 {                                                               \
  27         return pci_##op##_config_##size(dev, offset, value);    \
  28 }
  29
  30 DEFINE_PCI_CONFIG(read, byte, u8 *)
  31 DEFINE_PCI_CONFIG(read, word, u16 *)
  32 DEFINE_PCI_CONFIG(read, dword, u32 *)
  33
  34 DEFINE_PCI_CONFIG(write, byte, u8)
  35 DEFINE_PCI_CONFIG(write, word, u16)
  36 DEFINE_PCI_CONFIG(write, dword, u32)
  37
  38 static int conf_space_read(struct pci_dev *dev,
  39                            const struct config_field_entry *entry,
  40                            int offset, u32 *value)
  41 {
  42         int ret = 0;
  43         const struct config_field *field = entry->field;
  44
  45         *value = 0;
  46
  47         switch (field->size) {
  48         case 1:
  49                 if (field->u.b.read)
  50                         ret = field->u.b.read(dev, offset, (u8 *) value,
  51                                               entry->data);
  52                 break;
  53         case 2:
  54                 if (field->u.w.read)
  55                         ret = field->u.w.read(dev, offset, (u16 *) value,
  56                                               entry->data);
  57                 break;
  58         case 4:
  59                 if (field->u.dw.read)
  60                         ret = field->u.dw.read(dev, offset, value, entry->data);
  61                 break;
  62         }
  63         return ret;
  64 }
  65
  66 static int conf_space_write(struct pci_dev *dev,
  67                             const struct config_field_entry *entry,
  68                             int offset, u32 value)
  69 {
  70         int ret = 0;
  71         const struct config_field *field = entry->field;
  72
  73         switch (field->size) {
  74         case 1:
  75                 if (field->u.b.write)
  76                         ret = field->u.b.write(dev, offset, (u8) value,
  77                                                entry->data);
  78                 break;
  79         case 2:
  80                 if (field->u.w.write)
  81                         ret = field->u.w.write(dev, offset, (u16) value,
  82                                                entry->data);
  83                 break;
  84         case 4:
  85                 if (field->u.dw.write)
  86                         ret = field->u.dw.write(dev, offset, value,
  87                                                 entry->data);
  88                 break;
  89         }
  90         return ret;
  91 }
  92
  93 static inline u32 get_mask(int size)
  94 {
  95         if (size == 1)
  96                 return 0xff;
  97         else if (size == 2)
  98                 return 0xffff;
  99         else
 100                 return 0xffffffff;
 101 }
 102
 103 static inline int valid_request(int offset, int size)
 104 {
 105         /* Validate request (no un-aligned requests) */
 106         if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
 107                 return 1;
 108         return 0;
 109 }
 110
 111 static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
 112                               int offset)
 113 {
 114         if (offset >= 0) {
 115                 new_val_mask <<= (offset * 8);
 116                 new_val <<= (offset * 8);
 117         } else {
 118                 new_val_mask >>= (offset * -8);
 119                 new_val >>= (offset * -8);
 120         }
 121         val = (val & ~new_val_mask) | (new_val & new_val_mask);
 122
 123         return val;
 124 }
 125
 126 static int pcibios_err_to_errno(int err)
 127 {
 128         switch (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;
 139         }
 140         return err;
 141 }
 142
 143 int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
 144                           u32 *ret_val)
 145 {
 146         int err = 0;
 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;
 154
 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);
 158
 159         if (!valid_request(offset, size)) {
 160                 err = XEN_PCI_ERR_invalid_offset;
 161                 goto out;
 162         }
 163
 164         /* Get the real value first, then modify as appropriate */
 165         switch (size) {
 166         case 1:
 167                 err = pci_read_config_byte(dev, offset, (u8 *) &value);
 168                 break;
 169         case 2:
 170                 err = pci_read_config_word(dev, offset, (u16 *) &value);
 171                 break;
 172         case 4:
 173                 err = pci_read_config_dword(dev, offset, &value);
 174                 break;
 175         }
 176
 177         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 178                 field = cfg_entry->field;
 179
 180                 req_start = offset;
 181                 req_end = offset + size;
 182                 field_start = OFFSET(cfg_entry);
 183                 field_end = OFFSET(cfg_entry) + field->size;
 184
 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,
 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 pcibios_err_to_errno(err);
 205 }
 206
 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_start >= field_start && req_start < field_end)
 233                     || (req_end > field_start && req_end <= field_end)) {
 234                         tmp_val = 0;
 235
 236                         err = xen_pcibk_config_read(dev, field_start,
 237                                                   field->size, &tmp_val);
 238                         if (err)
 239                                 break;
 240
 241                         tmp_val = merge_value(tmp_val, value, get_mask(size),
 242                                               req_start - field_start);
 243
 244                         err = conf_space_write(dev, cfg_entry, field_start,
 245                                                tmp_val);
 246
 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.
 252                          */
 253                         handled = 1;
 254                 }
 255         }
 256
 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) {
 265                         switch (size) {
 266                         case 1:
 267                                 err = pci_write_config_byte(dev, offset,
 268                                                             (u8) value);
 269                                 break;
 270                         case 2:
 271                                 err = pci_write_config_word(dev, offset,
 272                                                             (u16) value);
 273                                 break;
 274                         case 4:
 275                                 err = pci_write_config_dword(dev, offset,
 276                                                              (u32) value);
 277                                 break;
 278                         }
 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);
 289                 }
 290         }
 291
 292         return pcibios_err_to_errno(err);
 293 }
 294
 295 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
 296 {
 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;
 300
 301         dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
 302                            "configuration space fields\n");
 303         if (!dev_data)
 304                 return;
 305
 306         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 307                 field = cfg_entry->field;
 308
 309                 if (field->clean) {
 310                         field->clean((struct config_field *)field);
 311
 312                         kfree(cfg_entry->data);
 313
 314                         list_del(&cfg_entry->list);
 315                         kfree(cfg_entry);
 316                 }
 317
 318         }
 319 }
 320
 321 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
 322 {
 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;
 326
 327         dev_dbg(&dev->dev, "resetting virtual configuration space\n");
 328         if (!dev_data)
 329                 return;
 330
 331         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 332                 field = cfg_entry->field;
 333
 334                 if (field->reset)
 335                         field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
 336         }
 337 }
 338
 339 void xen_pcibk_config_free_dev(struct pci_dev *dev)
 340 {
 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;
 344
 345         dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
 346         if (!dev_data)
 347                 return;
 348
 349         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 350                 list_del(&cfg_entry->list);
 351
 352                 field = cfg_entry->field;
 353
 354                 if (field->release)
 355                         field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
 356
 357                 kfree(cfg_entry);
 358         }
 359 }
 360
 361 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
 362                                     const struct config_field *field,
 363                                     unsigned int base_offset)
 364 {
 365         int err = 0;
 366         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 367         struct config_field_entry *cfg_entry;
 368         void *tmp;
 369
 370         cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
 371         if (!cfg_entry) {
 372                 err = -ENOMEM;
 373                 goto out;
 374         }
 375
 376         cfg_entry->data = NULL;
 377         cfg_entry->field = field;
 378         cfg_entry->base_offset = base_offset;
 379
 380         /* silently ignore duplicate fields */
 381         err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
 382         if (err)
 383                 goto out;
 384
 385         if (field->init) {
 386                 tmp = field->init(dev, OFFSET(cfg_entry));
 387
 388                 if (IS_ERR(tmp)) {
 389                         err = PTR_ERR(tmp);
 390                         goto out;
 391                 }
 392
 393                 cfg_entry->data = tmp;
 394         }
 395
 396         dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
 397                 OFFSET(cfg_entry));
 398         list_add_tail(&cfg_entry->list, &dev_data->config_fields);
 399
 400 out:
 401         if (err)
 402                 kfree(cfg_entry);
 403
 404         return err;
 405 }
 406
 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.
 410  */
 411 int xen_pcibk_config_init_dev(struct pci_dev *dev)
 412 {
 413         int err = 0;
 414         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 415
 416         dev_dbg(&dev->dev, "initializing virtual configuration space\n");
 417
 418         INIT_LIST_HEAD(&dev_data->config_fields);
 419
 420         err = xen_pcibk_config_header_add_fields(dev);
 421         if (err)
 422                 goto out;
 423
 424         err = xen_pcibk_config_capability_add_fields(dev);
 425         if (err)
 426                 goto out;
 427
 428         err = xen_pcibk_config_quirks_init(dev);
 429
 430 out:
 431         return err;
 432 }
 433
 434 int xen_pcibk_config_init(void)
 435 {
 436         return xen_pcibk_config_capability_init();
 437 }