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/module.h>
  14 #include <linux/pci.h>
  15 #include "pciback.h"
  16 #include "conf_space.h"
  17 #include "conf_space_quirks.h"
  18
  19 #define DRV_NAME        "xen-pciback"
  20 static int permissive;
  21 module_param(permissive, bool, 0644);
  22
  23 /* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,
  24  * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */
  25 #define DEFINE_PCI_CONFIG(op, size, type)                       \
  26 int xen_pcibk_##op##_config_##size                              \
  27 (struct pci_dev *dev, int offset, type value, void *data)       \
  28 {                                                               \
  29         return pci_##op##_config_##size(dev, offset, value);    \
  30 }
  31
  32 DEFINE_PCI_CONFIG(read, byte, u8 *)
  33 DEFINE_PCI_CONFIG(read, word, u16 *)
  34 DEFINE_PCI_CONFIG(read, dword, u32 *)
  35
  36 DEFINE_PCI_CONFIG(write, byte, u8)
  37 DEFINE_PCI_CONFIG(write, word, u16)
  38 DEFINE_PCI_CONFIG(write, dword, u32)
  39
  40 static int conf_space_read(struct pci_dev *dev,
  41                            const struct config_field_entry *entry,
  42                            int offset, u32 *value)
  43 {
  44         int ret = 0;
  45         const struct config_field *field = entry->field;
  46
  47         *value = 0;
  48
  49         switch (field->size) {
  50         case 1:
  51                 if (field->u.b.read)
  52                         ret = field->u.b.read(dev, offset, (u8 *) value,
  53                                               entry->data);
  54                 break;
  55         case 2:
  56                 if (field->u.w.read)
  57                         ret = field->u.w.read(dev, offset, (u16 *) value,
  58                                               entry->data);
  59                 break;
  60         case 4:
  61                 if (field->u.dw.read)
  62                         ret = field->u.dw.read(dev, offset, value, entry->data);
  63                 break;
  64         }
  65         return ret;
  66 }
  67
  68 static int conf_space_write(struct pci_dev *dev,
  69                             const struct config_field_entry *entry,
  70                             int offset, u32 value)
  71 {
  72         int ret = 0;
  73         const struct config_field *field = entry->field;
  74
  75         switch (field->size) {
  76         case 1:
  77                 if (field->u.b.write)
  78                         ret = field->u.b.write(dev, offset, (u8) value,
  79                                                entry->data);
  80                 break;
  81         case 2:
  82                 if (field->u.w.write)
  83                         ret = field->u.w.write(dev, offset, (u16) value,
  84                                                entry->data);
  85                 break;
  86         case 4:
  87                 if (field->u.dw.write)
  88                         ret = field->u.dw.write(dev, offset, value,
  89                                                 entry->data);
  90                 break;
  91         }
  92         return ret;
  93 }
  94
  95 static inline u32 get_mask(int size)
  96 {
  97         if (size == 1)
  98                 return 0xff;
  99         else if (size == 2)
 100                 return 0xffff;
 101         else
 102                 return 0xffffffff;
 103 }
 104
 105 static inline int valid_request(int offset, int size)
 106 {
 107         /* Validate request (no un-aligned requests) */
 108         if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
 109                 return 1;
 110         return 0;
 111 }
 112
 113 static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
 114                               int offset)
 115 {
 116         if (offset >= 0) {
 117                 new_val_mask <<= (offset * 8);
 118                 new_val <<= (offset * 8);
 119         } else {
 120                 new_val_mask >>= (offset * -8);
 121                 new_val >>= (offset * -8);
 122         }
 123         val = (val & ~new_val_mask) | (new_val & new_val_mask);
 124
 125         return val;
 126 }
 127
 128 static int pcibios_err_to_errno(int err)
 129 {
 130         switch (err) {
 131         case PCIBIOS_SUCCESSFUL:
 132                 return XEN_PCI_ERR_success;
 133         case PCIBIOS_DEVICE_NOT_FOUND:
 134                 return XEN_PCI_ERR_dev_not_found;
 135         case PCIBIOS_BAD_REGISTER_NUMBER:
 136                 return XEN_PCI_ERR_invalid_offset;
 137         case PCIBIOS_FUNC_NOT_SUPPORTED:
 138                 return XEN_PCI_ERR_not_implemented;
 139         case PCIBIOS_SET_FAILED:
 140                 return XEN_PCI_ERR_access_denied;
 141         }
 142         return err;
 143 }
 144
 145 int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
 146                           u32 *ret_val)
 147 {
 148         int err = 0;
 149         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 150         const struct config_field_entry *cfg_entry;
 151         const struct config_field *field;
 152         int req_start, req_end, field_start, field_end;
 153         /* if read fails for any reason, return 0
 154          * (as if device didn't respond) */
 155         u32 value = 0, tmp_val;
 156
 157         if (unlikely(verbose_request))
 158                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n",
 159                        pci_name(dev), size, offset);
 160
 161         if (!valid_request(offset, size)) {
 162                 err = XEN_PCI_ERR_invalid_offset;
 163                 goto out;
 164         }
 165
 166         /* Get the real value first, then modify as appropriate */
 167         switch (size) {
 168         case 1:
 169                 err = pci_read_config_byte(dev, offset, (u8 *) &value);
 170                 break;
 171         case 2:
 172                 err = pci_read_config_word(dev, offset, (u16 *) &value);
 173                 break;
 174         case 4:
 175                 err = pci_read_config_dword(dev, offset, &value);
 176                 break;
 177         }
 178
 179         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 180                 field = cfg_entry->field;
 181
 182                 req_start = offset;
 183                 req_end = offset + size;
 184                 field_start = OFFSET(cfg_entry);
 185                 field_end = OFFSET(cfg_entry) + field->size;
 186
 187                 if ((req_start >= field_start && req_start < field_end)
 188                     || (req_end > field_start && req_end <= field_end)) {
 189                         err = conf_space_read(dev, cfg_entry, field_start,
 190                                               &tmp_val);
 191                         if (err)
 192                                 goto out;
 193
 194                         value = merge_value(value, tmp_val,
 195                                             get_mask(field->size),
 196                                             field_start - req_start);
 197                 }
 198         }
 199
 200 out:
 201         if (unlikely(verbose_request))
 202                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
 203                        pci_name(dev), size, offset, value);
 204
 205         *ret_val = value;
 206         return pcibios_err_to_errno(err);
 207 }
 208
 209 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
 210 {
 211         int err = 0, handled = 0;
 212         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 213         const struct config_field_entry *cfg_entry;
 214         const struct config_field *field;
 215         u32 tmp_val;
 216         int req_start, req_end, field_start, field_end;
 217
 218         if (unlikely(verbose_request))
 219                 printk(KERN_DEBUG
 220                        DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
 221                        pci_name(dev), size, offset, value);
 222
 223         if (!valid_request(offset, size))
 224                 return XEN_PCI_ERR_invalid_offset;
 225
 226         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 227                 field = cfg_entry->field;
 228
 229                 req_start = offset;
 230                 req_end = offset + size;
 231                 field_start = OFFSET(cfg_entry);
 232                 field_end = OFFSET(cfg_entry) + field->size;
 233
 234                 if ((req_start >= field_start && req_start < field_end)
 235                     || (req_end > field_start && req_end <= field_end)) {
 236                         tmp_val = 0;
 237
 238                         err = xen_pcibk_config_read(dev, field_start,
 239                                                   field->size, &tmp_val);
 240                         if (err)
 241                                 break;
 242
 243                         tmp_val = merge_value(tmp_val, value, get_mask(size),
 244                                               req_start - field_start);
 245
 246                         err = conf_space_write(dev, cfg_entry, field_start,
 247                                                tmp_val);
 248
 249                         /* handled is set true here, but not every byte
 250                          * may have been written! Properly detecting if
 251                          * every byte is handled is unnecessary as the
 252                          * flag is used to detect devices that need
 253                          * special helpers to work correctly.
 254                          */
 255                         handled = 1;
 256                 }
 257         }
 258
 259         if (!handled && !err) {
 260                 /* By default, anything not specificially handled above is
 261                  * read-only. The permissive flag changes this behavior so
 262                  * that anything not specifically handled above is writable.
 263                  * This means that some fields may still be read-only because
 264                  * they have entries in the config_field list that intercept
 265                  * the write and do nothing. */
 266                 if (dev_data->permissive || permissive) {
 267                         switch (size) {
 268                         case 1:
 269                                 err = pci_write_config_byte(dev, offset,
 270                                                             (u8) value);
 271                                 break;
 272                         case 2:
 273                                 err = pci_write_config_word(dev, offset,
 274                                                             (u16) value);
 275                                 break;
 276                         case 4:
 277                                 err = pci_write_config_dword(dev, offset,
 278                                                              (u32) value);
 279                                 break;
 280                         }
 281                 } else if (!dev_data->warned_on_write) {
 282                         dev_data->warned_on_write = 1;
 283                         dev_warn(&dev->dev, "Driver tried to write to a "
 284                                  "read-only configuration space field at offset"
 285                                  " 0x%x, size %d. This may be harmless, but if "
 286                                  "you have problems with your device:\n"
 287                                  "1) see permissive attribute in sysfs\n"
 288                                  "2) report problems to the xen-devel "
 289                                  "mailing list along with details of your "
 290                                  "device obtained from lspci.\n", offset, size);
 291                 }
 292         }
 293
 294         return pcibios_err_to_errno(err);
 295 }
 296
 297 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
 298 {
 299         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 300         struct config_field_entry *cfg_entry, *t;
 301         const struct config_field *field;
 302
 303         dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
 304                            "configuration space fields\n");
 305         if (!dev_data)
 306                 return;
 307
 308         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 309                 field = cfg_entry->field;
 310
 311                 if (field->clean) {
 312                         field->clean((struct config_field *)field);
 313
 314                         kfree(cfg_entry->data);
 315
 316                         list_del(&cfg_entry->list);
 317                         kfree(cfg_entry);
 318                 }
 319
 320         }
 321 }
 322
 323 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
 324 {
 325         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 326         const struct config_field_entry *cfg_entry;
 327         const struct config_field *field;
 328
 329         dev_dbg(&dev->dev, "resetting virtual configuration space\n");
 330         if (!dev_data)
 331                 return;
 332
 333         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 334                 field = cfg_entry->field;
 335
 336                 if (field->reset)
 337                         field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
 338         }
 339 }
 340
 341 void xen_pcibk_config_free_dev(struct pci_dev *dev)
 342 {
 343         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 344         struct config_field_entry *cfg_entry, *t;
 345         const struct config_field *field;
 346
 347         dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
 348         if (!dev_data)
 349                 return;
 350
 351         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 352                 list_del(&cfg_entry->list);
 353
 354                 field = cfg_entry->field;
 355
 356                 if (field->release)
 357                         field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
 358
 359                 kfree(cfg_entry);
 360         }
 361 }
 362
 363 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
 364                                     const struct config_field *field,
 365                                     unsigned int base_offset)
 366 {
 367         int err = 0;
 368         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 369         struct config_field_entry *cfg_entry;
 370         void *tmp;
 371
 372         cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
 373         if (!cfg_entry) {
 374                 err = -ENOMEM;
 375                 goto out;
 376         }
 377
 378         cfg_entry->data = NULL;
 379         cfg_entry->field = field;
 380         cfg_entry->base_offset = base_offset;
 381
 382         /* silently ignore duplicate fields */
 383         err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
 384         if (err)
 385                 goto out;
 386
 387         if (field->init) {
 388                 tmp = field->init(dev, OFFSET(cfg_entry));
 389
 390                 if (IS_ERR(tmp)) {
 391                         err = PTR_ERR(tmp);
 392                         goto out;
 393                 }
 394
 395                 cfg_entry->data = tmp;
 396         }
 397
 398         dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
 399                 OFFSET(cfg_entry));
 400         list_add_tail(&cfg_entry->list, &dev_data->config_fields);
 401
 402 out:
 403         if (err)
 404                 kfree(cfg_entry);
 405
 406         return err;
 407 }
 408
 409 /* This sets up the device's virtual configuration space to keep track of
 410  * certain registers (like the base address registers (BARs) so that we can
 411  * keep the client from manipulating them directly.
 412  */
 413 int xen_pcibk_config_init_dev(struct pci_dev *dev)
 414 {
 415         int err = 0;
 416         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 417
 418         dev_dbg(&dev->dev, "initializing virtual configuration space\n");
 419
 420         INIT_LIST_HEAD(&dev_data->config_fields);
 421
 422         err = xen_pcibk_config_header_add_fields(dev);
 423         if (err)
 424                 goto out;
 425
 426         err = xen_pcibk_config_capability_add_fields(dev);
 427         if (err)
 428                 goto out;
 429
 430         err = xen_pcibk_config_quirks_init(dev);
 431
 432 out:
 433         return err;
 434 }
 435
 436 int xen_pcibk_config_init(void)
 437 {
 438         return xen_pcibk_config_capability_init();
 439 }