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 static bool permissive;
  20 module_param(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 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 req_start, req_end, 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                 req_start = offset;
 182                 req_end = offset + size;
 183                 field_start = OFFSET(cfg_entry);
 184                 field_end = OFFSET(cfg_entry) + field->size;
 185
 186                 if ((req_start >= field_start && req_start < field_end)
 187                     || (req_end > field_start && req_end <= field_end)) {
 188                         err = conf_space_read(dev, cfg_entry, field_start,
 189                                               &tmp_val);
 190                         if (err)
 191                                 goto out;
 192
 193                         value = merge_value(value, tmp_val,
 194                                             get_mask(field->size),
 195                                             field_start - req_start);
 196                 }
 197         }
 198
 199 out:
 200         if (unlikely(verbose_request))
 201                 printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
 202                        pci_name(dev), size, offset, value);
 203
 204         *ret_val = value;
 205         return pcibios_err_to_errno(err);
 206 }
 207
 208 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
 209 {
 210         int err = 0, handled = 0;
 211         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 212         const struct config_field_entry *cfg_entry;
 213         const struct config_field *field;
 214         u32 tmp_val;
 215         int req_start, req_end, field_start, field_end;
 216
 217         if (unlikely(verbose_request))
 218                 printk(KERN_DEBUG
 219                        DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
 220                        pci_name(dev), size, offset, value);
 221
 222         if (!valid_request(offset, size))
 223                 return XEN_PCI_ERR_invalid_offset;
 224
 225         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 226                 field = cfg_entry->field;
 227
 228                 req_start = offset;
 229                 req_end = offset + size;
 230                 field_start = OFFSET(cfg_entry);
 231                 field_end = OFFSET(cfg_entry) + field->size;
 232
 233                 if ((req_start >= field_start && req_start < field_end)
 234                     || (req_end > field_start && req_end <= field_end)) {
 235                         tmp_val = 0;
 236
 237                         err = xen_pcibk_config_read(dev, field_start,
 238                                                   field->size, &tmp_val);
 239                         if (err)
 240                                 break;
 241
 242                         tmp_val = merge_value(tmp_val, value, get_mask(size),
 243                                               req_start - field_start);
 244
 245                         err = conf_space_write(dev, cfg_entry, field_start,
 246                                                tmp_val);
 247
 248                         /* handled is set true here, but not every byte
 249                          * may have been written! Properly detecting if
 250                          * every byte is handled is unnecessary as the
 251                          * flag is used to detect devices that need
 252                          * special helpers to work correctly.
 253                          */
 254                         handled = 1;
 255                 }
 256         }
 257
 258         if (!handled && !err) {
 259                 /* By default, anything not specificially handled above is
 260                  * read-only. The permissive flag changes this behavior so
 261                  * that anything not specifically handled above is writable.
 262                  * This means that some fields may still be read-only because
 263                  * they have entries in the config_field list that intercept
 264                  * the write and do nothing. */
 265                 if (dev_data->permissive || permissive) {
 266                         switch (size) {
 267                         case 1:
 268                                 err = pci_write_config_byte(dev, offset,
 269                                                             (u8) value);
 270                                 break;
 271                         case 2:
 272                                 err = pci_write_config_word(dev, offset,
 273                                                             (u16) value);
 274                                 break;
 275                         case 4:
 276                                 err = pci_write_config_dword(dev, offset,
 277                                                              (u32) value);
 278                                 break;
 279                         }
 280                 } else if (!dev_data->warned_on_write) {
 281                         dev_data->warned_on_write = 1;
 282                         dev_warn(&dev->dev, "Driver tried to write to a "
 283                                  "read-only configuration space field at offset"
 284                                  " 0x%x, size %d. This may be harmless, but if "
 285                                  "you have problems with your device:\n"
 286                                  "1) see permissive attribute in sysfs\n"
 287                                  "2) report problems to the xen-devel "
 288                                  "mailing list along with details of your "
 289                                  "device obtained from lspci.\n", offset, size);
 290                 }
 291         }
 292
 293         return pcibios_err_to_errno(err);
 294 }
 295
 296 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
 297 {
 298         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 299         struct config_field_entry *cfg_entry, *t;
 300         const struct config_field *field;
 301
 302         dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
 303                            "configuration space fields\n");
 304         if (!dev_data)
 305                 return;
 306
 307         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 308                 field = cfg_entry->field;
 309
 310                 if (field->clean) {
 311                         field->clean((struct config_field *)field);
 312
 313                         kfree(cfg_entry->data);
 314
 315                         list_del(&cfg_entry->list);
 316                         kfree(cfg_entry);
 317                 }
 318
 319         }
 320 }
 321
 322 void xen_pcibk_config_reset_dev(struct pci_dev *dev)
 323 {
 324         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 325         const struct config_field_entry *cfg_entry;
 326         const struct config_field *field;
 327
 328         dev_dbg(&dev->dev, "resetting virtual configuration space\n");
 329         if (!dev_data)
 330                 return;
 331
 332         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 333                 field = cfg_entry->field;
 334
 335                 if (field->reset)
 336                         field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
 337         }
 338 }
 339
 340 void xen_pcibk_config_free_dev(struct pci_dev *dev)
 341 {
 342         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 343         struct config_field_entry *cfg_entry, *t;
 344         const struct config_field *field;
 345
 346         dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
 347         if (!dev_data)
 348                 return;
 349
 350         list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
 351                 list_del(&cfg_entry->list);
 352
 353                 field = cfg_entry->field;
 354
 355                 if (field->release)
 356                         field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
 357
 358                 kfree(cfg_entry);
 359         }
 360 }
 361
 362 int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
 363                                     const struct config_field *field,
 364                                     unsigned int base_offset)
 365 {
 366         int err = 0;
 367         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 368         struct config_field_entry *cfg_entry;
 369         void *tmp;
 370
 371         cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
 372         if (!cfg_entry) {
 373                 err = -ENOMEM;
 374                 goto out;
 375         }
 376
 377         cfg_entry->data = NULL;
 378         cfg_entry->field = field;
 379         cfg_entry->base_offset = base_offset;
 380
 381         /* silently ignore duplicate fields */
 382         err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
 383         if (err)
 384                 goto out;
 385
 386         if (field->init) {
 387                 tmp = field->init(dev, OFFSET(cfg_entry));
 388
 389                 if (IS_ERR(tmp)) {
 390                         err = PTR_ERR(tmp);
 391                         goto out;
 392                 }
 393
 394                 cfg_entry->data = tmp;
 395         }
 396
 397         dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
 398                 OFFSET(cfg_entry));
 399         list_add_tail(&cfg_entry->list, &dev_data->config_fields);
 400
 401 out:
 402         if (err)
 403                 kfree(cfg_entry);
 404
 405         return err;
 406 }
 407
 408 /* This sets up the device's virtual configuration space to keep track of
 409  * certain registers (like the base address registers (BARs) so that we can
 410  * keep the client from manipulating them directly.
 411  */
 412 int xen_pcibk_config_init_dev(struct pci_dev *dev)
 413 {
 414         int err = 0;
 415         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 416
 417         dev_dbg(&dev->dev, "initializing virtual configuration space\n");
 418
 419         INIT_LIST_HEAD(&dev_data->config_fields);
 420
 421         err = xen_pcibk_config_header_add_fields(dev);
 422         if (err)
 423                 goto out;
 424
 425         err = xen_pcibk_config_capability_add_fields(dev);
 426         if (err)
 427                 goto out;
 428
 429         err = xen_pcibk_config_quirks_init(dev);
 430
 431 out:
 432         return err;
 433 }
 434
 435 int xen_pcibk_config_init(void)
 436 {
 437         return xen_pcibk_config_capability_init();
 438 }