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1// SPDX-License-Identifier: GPL-2.02/*3 * PCI Backend - Functions for creating a virtual configuration space for4 * exported PCI Devices.5 * It's dangerous to allow PCI Driver Domains to change their6 * device's resources (memory, i/o ports, interrupts). We need to7 * restrict changes to certain PCI Configuration registers:8 * BARs, INTERRUPT_PIN, most registers in the header...9 *10 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>11 */12 13#define dev_fmt(fmt) DRV_NAME ": " fmt14 15#include <linux/kernel.h>16#include <linux/moduleparam.h>17#include <linux/pci.h>18#include "pciback.h"19#include "conf_space.h"20#include "conf_space_quirks.h"21 22bool xen_pcibk_permissive;23module_param_named(permissive, xen_pcibk_permissive, bool, 0644);24 25/* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,26 * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */27#define DEFINE_PCI_CONFIG(op, size, type) \28int xen_pcibk_##op##_config_##size \29(struct pci_dev *dev, int offset, type value, void *data) \30{ \31 return pci_##op##_config_##size(dev, offset, value); \32}33 34DEFINE_PCI_CONFIG(read, byte, u8 *)35DEFINE_PCI_CONFIG(read, word, u16 *)36DEFINE_PCI_CONFIG(read, dword, u32 *)37 38DEFINE_PCI_CONFIG(write, byte, u8)39DEFINE_PCI_CONFIG(write, word, u16)40DEFINE_PCI_CONFIG(write, dword, u32)41 42static int conf_space_read(struct pci_dev *dev,43 const struct config_field_entry *entry,44 int offset, u32 *value)45{46 int ret = 0;47 const struct config_field *field = entry->field;48 49 *value = 0;50 51 switch (field->size) {52 case 1:53 if (field->u.b.read)54 ret = field->u.b.read(dev, offset, (u8 *) value,55 entry->data);56 break;57 case 2:58 if (field->u.w.read)59 ret = field->u.w.read(dev, offset, (u16 *) value,60 entry->data);61 break;62 case 4:63 if (field->u.dw.read)64 ret = field->u.dw.read(dev, offset, value, entry->data);65 break;66 }67 return ret;68}69 70static int conf_space_write(struct pci_dev *dev,71 const struct config_field_entry *entry,72 int offset, u32 value)73{74 int ret = 0;75 const struct config_field *field = entry->field;76 77 switch (field->size) {78 case 1:79 if (field->u.b.write)80 ret = field->u.b.write(dev, offset, (u8) value,81 entry->data);82 break;83 case 2:84 if (field->u.w.write)85 ret = field->u.w.write(dev, offset, (u16) value,86 entry->data);87 break;88 case 4:89 if (field->u.dw.write)90 ret = field->u.dw.write(dev, offset, value,91 entry->data);92 break;93 }94 return ret;95}96 97static inline u32 get_mask(int size)98{99 if (size == 1)100 return 0xff;101 else if (size == 2)102 return 0xffff;103 else104 return 0xffffffff;105}106 107static inline int valid_request(int offset, int size)108{109 /* Validate request (no un-aligned requests) */110 if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)111 return 1;112 return 0;113}114 115static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,116 int offset)117{118 if (offset >= 0) {119 new_val_mask <<= (offset * 8);120 new_val <<= (offset * 8);121 } else {122 new_val_mask >>= (offset * -8);123 new_val >>= (offset * -8);124 }125 val = (val & ~new_val_mask) | (new_val & new_val_mask);126 127 return val;128}129 130static int xen_pcibios_err_to_errno(int err)131{132 switch (err) {133 case PCIBIOS_SUCCESSFUL:134 return XEN_PCI_ERR_success;135 case PCIBIOS_DEVICE_NOT_FOUND:136 return XEN_PCI_ERR_dev_not_found;137 case PCIBIOS_BAD_REGISTER_NUMBER:138 return XEN_PCI_ERR_invalid_offset;139 case PCIBIOS_FUNC_NOT_SUPPORTED:140 return XEN_PCI_ERR_not_implemented;141 case PCIBIOS_SET_FAILED:142 return XEN_PCI_ERR_access_denied;143 }144 return err;145}146 147int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,148 u32 *ret_val)149{150 int err = 0;151 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);152 const struct config_field_entry *cfg_entry;153 const struct config_field *field;154 int field_start, field_end;155 /* if read fails for any reason, return 0156 * (as if device didn't respond) */157 u32 value = 0, tmp_val;158 159 dev_dbg(&dev->dev, "read %d bytes at 0x%x\n", 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 field_start = OFFSET(cfg_entry);183 field_end = OFFSET(cfg_entry) + field->size;184 185 if (offset + size > field_start && field_end > offset) {186 err = conf_space_read(dev, cfg_entry, field_start,187 &tmp_val);188 if (err)189 goto out;190 191 value = merge_value(value, tmp_val,192 get_mask(field->size),193 field_start - offset);194 }195 }196 197out:198 dev_dbg(&dev->dev, "read %d bytes at 0x%x = %x\n", size, offset, value);199 200 *ret_val = value;201 return xen_pcibios_err_to_errno(err);202}203 204int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)205{206 int err = 0, handled = 0;207 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);208 const struct config_field_entry *cfg_entry;209 const struct config_field *field;210 u32 tmp_val;211 int field_start, field_end;212 213 dev_dbg(&dev->dev, "write request %d bytes at 0x%x = %x\n",214 size, offset, value);215 216 if (!valid_request(offset, size))217 return XEN_PCI_ERR_invalid_offset;218 219 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {220 field = cfg_entry->field;221 222 field_start = OFFSET(cfg_entry);223 field_end = OFFSET(cfg_entry) + field->size;224 225 if (offset + size > field_start && field_end > offset) {226 err = conf_space_read(dev, cfg_entry, field_start,227 &tmp_val);228 if (err)229 break;230 231 tmp_val = merge_value(tmp_val, value, get_mask(size),232 offset - field_start);233 234 err = conf_space_write(dev, cfg_entry, field_start,235 tmp_val);236 237 /* handled is set true here, but not every byte238 * may have been written! Properly detecting if239 * every byte is handled is unnecessary as the240 * flag is used to detect devices that need241 * special helpers to work correctly.242 */243 handled = 1;244 }245 }246 247 if (!handled && !err) {248 /* By default, anything not specificially handled above is249 * read-only. The permissive flag changes this behavior so250 * that anything not specifically handled above is writable.251 * This means that some fields may still be read-only because252 * they have entries in the config_field list that intercept253 * the write and do nothing. */254 if (dev_data->permissive || xen_pcibk_permissive) {255 switch (size) {256 case 1:257 err = pci_write_config_byte(dev, offset,258 (u8) value);259 break;260 case 2:261 err = pci_write_config_word(dev, offset,262 (u16) value);263 break;264 case 4:265 err = pci_write_config_dword(dev, offset,266 (u32) value);267 break;268 }269 } else if (!dev_data->warned_on_write) {270 dev_data->warned_on_write = 1;271 dev_warn(&dev->dev, "Driver tried to write to a "272 "read-only configuration space field at offset"273 " 0x%x, size %d. This may be harmless, but if "274 "you have problems with your device:\n"275 "1) see permissive attribute in sysfs\n"276 "2) report problems to the xen-devel "277 "mailing list along with details of your "278 "device obtained from lspci.\n", offset, size);279 }280 }281 282 return xen_pcibios_err_to_errno(err);283}284 285int xen_pcibk_get_interrupt_type(struct pci_dev *dev)286{287 int err;288 u16 val;289 int ret = 0;290 291 /*292 * Do not trust dev->msi(x)_enabled here, as enabling could be done293 * bypassing the pci_*msi* functions, by the qemu.294 */295 if (dev->msi_cap) {296 err = pci_read_config_word(dev,297 dev->msi_cap + PCI_MSI_FLAGS,298 &val);299 if (err)300 return err;301 if (val & PCI_MSI_FLAGS_ENABLE)302 ret |= INTERRUPT_TYPE_MSI;303 }304 if (dev->msix_cap) {305 err = pci_read_config_word(dev,306 dev->msix_cap + PCI_MSIX_FLAGS,307 &val);308 if (err)309 return err;310 if (val & PCI_MSIX_FLAGS_ENABLE)311 ret |= INTERRUPT_TYPE_MSIX;312 }313 314 /*315 * PCIe spec says device cannot use INTx if MSI/MSI-X is enabled,316 * so check for INTx only when both are disabled.317 */318 if (!ret) {319 err = pci_read_config_word(dev, PCI_COMMAND, &val);320 if (err)321 return err;322 if (!(val & PCI_COMMAND_INTX_DISABLE))323 ret |= INTERRUPT_TYPE_INTX;324 }325 326 return ret ?: INTERRUPT_TYPE_NONE;327}328 329void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)330{331 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);332 struct config_field_entry *cfg_entry, *t;333 const struct config_field *field;334 335 dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "336 "configuration space fields\n");337 if (!dev_data)338 return;339 340 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {341 field = cfg_entry->field;342 343 if (field->clean) {344 field->clean((struct config_field *)field);345 346 kfree(cfg_entry->data);347 348 list_del(&cfg_entry->list);349 kfree(cfg_entry);350 }351 352 }353}354 355void xen_pcibk_config_reset_dev(struct pci_dev *dev)356{357 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);358 const struct config_field_entry *cfg_entry;359 const struct config_field *field;360 361 dev_dbg(&dev->dev, "resetting virtual configuration space\n");362 if (!dev_data)363 return;364 365 list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {366 field = cfg_entry->field;367 368 if (field->reset)369 field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);370 }371}372 373void xen_pcibk_config_free_dev(struct pci_dev *dev)374{375 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);376 struct config_field_entry *cfg_entry, *t;377 const struct config_field *field;378 379 dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");380 if (!dev_data)381 return;382 383 list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {384 list_del(&cfg_entry->list);385 386 field = cfg_entry->field;387 388 if (field->release)389 field->release(dev, OFFSET(cfg_entry), cfg_entry->data);390 391 kfree(cfg_entry);392 }393}394 395int xen_pcibk_config_add_field_offset(struct pci_dev *dev,396 const struct config_field *field,397 unsigned int base_offset)398{399 int err = 0;400 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);401 struct config_field_entry *cfg_entry;402 void *tmp;403 404 cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);405 if (!cfg_entry) {406 err = -ENOMEM;407 goto out;408 }409 410 cfg_entry->data = NULL;411 cfg_entry->field = field;412 cfg_entry->base_offset = base_offset;413 414 /* silently ignore duplicate fields */415 err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));416 if (err)417 goto out;418 419 if (field->init) {420 tmp = field->init(dev, OFFSET(cfg_entry));421 422 if (IS_ERR(tmp)) {423 err = PTR_ERR(tmp);424 goto out;425 }426 427 cfg_entry->data = tmp;428 }429 430 dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",431 OFFSET(cfg_entry));432 list_add_tail(&cfg_entry->list, &dev_data->config_fields);433 434out:435 if (err)436 kfree(cfg_entry);437 438 return err;439}440 441/* This sets up the device's virtual configuration space to keep track of442 * certain registers (like the base address registers (BARs) so that we can443 * keep the client from manipulating them directly.444 */445int xen_pcibk_config_init_dev(struct pci_dev *dev)446{447 int err = 0;448 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);449 450 dev_dbg(&dev->dev, "initializing virtual configuration space\n");451 452 INIT_LIST_HEAD(&dev_data->config_fields);453 454 err = xen_pcibk_config_header_add_fields(dev);455 if (err)456 goto out;457 458 err = xen_pcibk_config_capability_add_fields(dev);459 if (err)460 goto out;461 462 err = xen_pcibk_config_quirks_init(dev);463 464out:465 return err;466}467 468int xen_pcibk_config_init(void)469{470 return xen_pcibk_config_capability_init();471}472