1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Xen PCI Frontend 4 * 5 * Author: Ryan Wilson <hap9@epoch.ncsc.mil> 6 */ 7#include <linux/module.h> 8#include <linux/init.h> 9#include <linux/mm.h> 10#include <xen/xenbus.h> 11#include <xen/events.h> 12#include <xen/grant_table.h> 13#include <xen/page.h> 14#include <linux/spinlock.h> 15#include <linux/pci.h> 16#include <linux/msi.h> 17#include <xen/interface/io/pciif.h> 18#include <asm/xen/pci.h> 19#include <linux/interrupt.h> 20#include <linux/atomic.h> 21#include <linux/workqueue.h> 22#include <linux/bitops.h> 23#include <linux/time.h> 24#include <linux/ktime.h> 25#include <xen/platform_pci.h> 26 27#include <asm/xen/swiotlb-xen.h> 28 29#define INVALID_EVTCHN (-1) 30 31struct pci_bus_entry { 32 struct list_head list; 33 struct pci_bus *bus; 34}; 35 36#define _PDEVB_op_active (0) 37#define PDEVB_op_active (1 << (_PDEVB_op_active)) 38 39struct pcifront_device { 40 struct xenbus_device *xdev; 41 struct list_head root_buses; 42 43 int evtchn; 44 grant_ref_t gnt_ref; 45 46 int irq; 47 48 /* Lock this when doing any operations in sh_info */ 49 spinlock_t sh_info_lock; 50 struct xen_pci_sharedinfo *sh_info; 51 struct work_struct op_work; 52 unsigned long flags; 53 54}; 55 56struct pcifront_sd { 57 struct pci_sysdata sd; 58 struct pcifront_device *pdev; 59}; 60 61static inline struct pcifront_device * 62pcifront_get_pdev(struct pcifront_sd *sd) 63{ 64 return sd->pdev; 65} 66 67static inline void pcifront_init_sd(struct pcifront_sd *sd, 68 unsigned int domain, unsigned int bus, 69 struct pcifront_device *pdev) 70{ 71 /* Because we do not expose that information via XenBus. */ 72 sd->sd.node = first_online_node; 73 sd->sd.domain = domain; 74 sd->pdev = pdev; 75} 76 77static DEFINE_SPINLOCK(pcifront_dev_lock); 78static struct pcifront_device *pcifront_dev; 79 80static int errno_to_pcibios_err(int errno) 81{ 82 switch (errno) { 83 case XEN_PCI_ERR_success: 84 return PCIBIOS_SUCCESSFUL; 85 86 case XEN_PCI_ERR_dev_not_found: 87 return PCIBIOS_DEVICE_NOT_FOUND; 88 89 case XEN_PCI_ERR_invalid_offset: 90 case XEN_PCI_ERR_op_failed: 91 return PCIBIOS_BAD_REGISTER_NUMBER; 92 93 case XEN_PCI_ERR_not_implemented: 94 return PCIBIOS_FUNC_NOT_SUPPORTED; 95 96 case XEN_PCI_ERR_access_denied: 97 return PCIBIOS_SET_FAILED; 98 } 99 return errno; 100} 101 102static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev) 103{ 104 if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags) 105 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) { 106 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n"); 107 schedule_work(&pdev->op_work); 108 } 109} 110 111static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op) 112{ 113 int err = 0; 114 struct xen_pci_op *active_op = &pdev->sh_info->op; 115 unsigned long irq_flags; 116 evtchn_port_t port = pdev->evtchn; 117 unsigned int irq = pdev->irq; 118 s64 ns, ns_timeout; 119 120 spin_lock_irqsave(&pdev->sh_info_lock, irq_flags); 121 122 memcpy(active_op, op, sizeof(struct xen_pci_op)); 123 124 /* Go */ 125 wmb(); 126 set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); 127 notify_remote_via_evtchn(port); 128 129 /* 130 * We set a poll timeout of 3 seconds but give up on return after 131 * 2 seconds. It is better to time out too late rather than too early 132 * (in the latter case we end up continually re-executing poll() with a 133 * timeout in the past). 1s difference gives plenty of slack for error. 134 */ 135 ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC; 136 137 xen_clear_irq_pending(irq); 138 139 while (test_bit(_XEN_PCIF_active, 140 (unsigned long *)&pdev->sh_info->flags)) { 141 xen_poll_irq_timeout(irq, jiffies + 3*HZ); 142 xen_clear_irq_pending(irq); 143 ns = ktime_get_ns(); 144 if (ns > ns_timeout) { 145 dev_err(&pdev->xdev->dev, 146 "pciback not responding!!!\n"); 147 clear_bit(_XEN_PCIF_active, 148 (unsigned long *)&pdev->sh_info->flags); 149 err = XEN_PCI_ERR_dev_not_found; 150 goto out; 151 } 152 } 153 154 /* 155 * We might lose backend service request since we 156 * reuse same evtchn with pci_conf backend response. So re-schedule 157 * aer pcifront service. 158 */ 159 if (test_bit(_XEN_PCIB_active, 160 (unsigned long *)&pdev->sh_info->flags)) { 161 dev_err(&pdev->xdev->dev, 162 "schedule aer pcifront service\n"); 163 schedule_pcifront_aer_op(pdev); 164 } 165 166 memcpy(op, active_op, sizeof(struct xen_pci_op)); 167 168 err = op->err; 169out: 170 spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags); 171 return err; 172} 173 174/* Access to this function is spinlocked in drivers/pci/access.c */ 175static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn, 176 int where, int size, u32 *val) 177{ 178 int err = 0; 179 struct xen_pci_op op = { 180 .cmd = XEN_PCI_OP_conf_read, 181 .domain = pci_domain_nr(bus), 182 .bus = bus->number, 183 .devfn = devfn, 184 .offset = where, 185 .size = size, 186 }; 187 struct pcifront_sd *sd = bus->sysdata; 188 struct pcifront_device *pdev = pcifront_get_pdev(sd); 189 190 dev_dbg(&pdev->xdev->dev, 191 "read dev=%04x:%02x:%02x.%d - offset %x size %d\n", 192 pci_domain_nr(bus), bus->number, PCI_SLOT(devfn), 193 PCI_FUNC(devfn), where, size); 194 195 err = do_pci_op(pdev, &op); 196 197 if (likely(!err)) { 198 dev_dbg(&pdev->xdev->dev, "read got back value %x\n", 199 op.value); 200 201 *val = op.value; 202 } else if (err == -ENODEV) { 203 /* No device here, pretend that it just returned 0 */ 204 err = 0; 205 *val = 0; 206 } 207 208 return errno_to_pcibios_err(err); 209} 210 211/* Access to this function is spinlocked in drivers/pci/access.c */ 212static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn, 213 int where, int size, u32 val) 214{ 215 struct xen_pci_op op = { 216 .cmd = XEN_PCI_OP_conf_write, 217 .domain = pci_domain_nr(bus), 218 .bus = bus->number, 219 .devfn = devfn, 220 .offset = where, 221 .size = size, 222 .value = val, 223 }; 224 struct pcifront_sd *sd = bus->sysdata; 225 struct pcifront_device *pdev = pcifront_get_pdev(sd); 226 227 dev_dbg(&pdev->xdev->dev, 228 "write dev=%04x:%02x:%02x.%d - offset %x size %d val %x\n", 229 pci_domain_nr(bus), bus->number, 230 PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val); 231 232 return errno_to_pcibios_err(do_pci_op(pdev, &op)); 233} 234 235static struct pci_ops pcifront_bus_ops = { 236 .read = pcifront_bus_read, 237 .write = pcifront_bus_write, 238}; 239 240#ifdef CONFIG_PCI_MSI 241static int pci_frontend_enable_msix(struct pci_dev *dev, 242 int vector[], int nvec) 243{ 244 int err; 245 int i; 246 struct xen_pci_op op = { 247 .cmd = XEN_PCI_OP_enable_msix, 248 .domain = pci_domain_nr(dev->bus), 249 .bus = dev->bus->number, 250 .devfn = dev->devfn, 251 .value = nvec, 252 }; 253 struct pcifront_sd *sd = dev->bus->sysdata; 254 struct pcifront_device *pdev = pcifront_get_pdev(sd); 255 struct msi_desc *entry; 256 257 if (nvec > SH_INFO_MAX_VEC) { 258 pci_err(dev, "too many vectors (0x%x) for PCI frontend:" 259 " Increase SH_INFO_MAX_VEC\n", nvec); 260 return -EINVAL; 261 } 262 263 i = 0; 264 msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) { 265 op.msix_entries[i].entry = entry->msi_index; 266 /* Vector is useless at this point. */ 267 op.msix_entries[i].vector = -1; 268 i++; 269 } 270 271 err = do_pci_op(pdev, &op); 272 273 if (likely(!err)) { 274 if (likely(!op.value)) { 275 /* we get the result */ 276 for (i = 0; i < nvec; i++) { 277 if (op.msix_entries[i].vector <= 0) { 278 pci_warn(dev, "MSI-X entry %d is invalid: %d!\n", 279 i, op.msix_entries[i].vector); 280 err = -EINVAL; 281 vector[i] = -1; 282 continue; 283 } 284 vector[i] = op.msix_entries[i].vector; 285 } 286 } else { 287 pr_info("enable msix get value %x\n", op.value); 288 err = op.value; 289 } 290 } else { 291 pci_err(dev, "enable msix get err %x\n", err); 292 } 293 return err; 294} 295 296static void pci_frontend_disable_msix(struct pci_dev *dev) 297{ 298 int err; 299 struct xen_pci_op op = { 300 .cmd = XEN_PCI_OP_disable_msix, 301 .domain = pci_domain_nr(dev->bus), 302 .bus = dev->bus->number, 303 .devfn = dev->devfn, 304 }; 305 struct pcifront_sd *sd = dev->bus->sysdata; 306 struct pcifront_device *pdev = pcifront_get_pdev(sd); 307 308 err = do_pci_op(pdev, &op); 309 310 /* What should do for error ? */ 311 if (err) 312 pci_err(dev, "pci_disable_msix get err %x\n", err); 313} 314 315static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[]) 316{ 317 int err; 318 struct xen_pci_op op = { 319 .cmd = XEN_PCI_OP_enable_msi, 320 .domain = pci_domain_nr(dev->bus), 321 .bus = dev->bus->number, 322 .devfn = dev->devfn, 323 }; 324 struct pcifront_sd *sd = dev->bus->sysdata; 325 struct pcifront_device *pdev = pcifront_get_pdev(sd); 326 327 err = do_pci_op(pdev, &op); 328 if (likely(!err)) { 329 vector[0] = op.value; 330 if (op.value <= 0) { 331 pci_warn(dev, "MSI entry is invalid: %d!\n", 332 op.value); 333 err = -EINVAL; 334 vector[0] = -1; 335 } 336 } else { 337 pci_err(dev, "pci frontend enable msi failed for dev " 338 "%x:%x\n", op.bus, op.devfn); 339 err = -EINVAL; 340 } 341 return err; 342} 343 344static void pci_frontend_disable_msi(struct pci_dev *dev) 345{ 346 int err; 347 struct xen_pci_op op = { 348 .cmd = XEN_PCI_OP_disable_msi, 349 .domain = pci_domain_nr(dev->bus), 350 .bus = dev->bus->number, 351 .devfn = dev->devfn, 352 }; 353 struct pcifront_sd *sd = dev->bus->sysdata; 354 struct pcifront_device *pdev = pcifront_get_pdev(sd); 355 356 err = do_pci_op(pdev, &op); 357 if (err == XEN_PCI_ERR_dev_not_found) { 358 /* XXX No response from backend, what shall we do? */ 359 pr_info("get no response from backend for disable MSI\n"); 360 return; 361 } 362 if (err) 363 /* how can pciback notify us fail? */ 364 pr_info("get fake response from backend\n"); 365} 366 367static struct xen_pci_frontend_ops pci_frontend_ops = { 368 .enable_msi = pci_frontend_enable_msi, 369 .disable_msi = pci_frontend_disable_msi, 370 .enable_msix = pci_frontend_enable_msix, 371 .disable_msix = pci_frontend_disable_msix, 372}; 373 374static void pci_frontend_registrar(int enable) 375{ 376 if (enable) 377 xen_pci_frontend = &pci_frontend_ops; 378 else 379 xen_pci_frontend = NULL; 380}; 381#else 382static inline void pci_frontend_registrar(int enable) { }; 383#endif /* CONFIG_PCI_MSI */ 384 385/* Claim resources for the PCI frontend as-is, backend won't allow changes */ 386static int pcifront_claim_resource(struct pci_dev *dev, void *data) 387{ 388 struct pcifront_device *pdev = data; 389 int i; 390 struct resource *r; 391 392 pci_dev_for_each_resource(dev, r, i) { 393 if (!r->parent && r->start && r->flags) { 394 dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n", 395 pci_name(dev), i); 396 if (pci_claim_resource(dev, i)) { 397 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! " 398 "Device offline. Try using e820_host=1 in the guest config.\n", 399 pci_name(dev), i); 400 } 401 } 402 } 403 404 return 0; 405} 406 407static int pcifront_scan_bus(struct pcifront_device *pdev, 408 unsigned int domain, unsigned int bus, 409 struct pci_bus *b) 410{ 411 struct pci_dev *d; 412 unsigned int devfn; 413 414 /* 415 * Scan the bus for functions and add. 416 * We omit handling of PCI bridge attachment because pciback prevents 417 * bridges from being exported. 418 */ 419 for (devfn = 0; devfn < 0x100; devfn++) { 420 d = pci_get_slot(b, devfn); 421 if (d) { 422 /* Device is already known. */ 423 pci_dev_put(d); 424 continue; 425 } 426 427 d = pci_scan_single_device(b, devfn); 428 if (d) 429 dev_info(&pdev->xdev->dev, "New device on " 430 "%04x:%02x:%02x.%d found.\n", domain, bus, 431 PCI_SLOT(devfn), PCI_FUNC(devfn)); 432 } 433 434 return 0; 435} 436 437static int pcifront_scan_root(struct pcifront_device *pdev, 438 unsigned int domain, unsigned int bus) 439{ 440 struct pci_bus *b; 441 LIST_HEAD(resources); 442 struct pcifront_sd *sd = NULL; 443 struct pci_bus_entry *bus_entry = NULL; 444 int err = 0; 445 static struct resource busn_res = { 446 .start = 0, 447 .end = 255, 448 .flags = IORESOURCE_BUS, 449 }; 450 451#ifndef CONFIG_PCI_DOMAINS 452 if (domain != 0) { 453 dev_err(&pdev->xdev->dev, 454 "PCI Root in non-zero PCI Domain! domain=%d\n", domain); 455 dev_err(&pdev->xdev->dev, 456 "Please compile with CONFIG_PCI_DOMAINS\n"); 457 err = -EINVAL; 458 goto err_out; 459 } 460#endif 461 462 dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n", 463 domain, bus); 464 465 bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL); 466 sd = kzalloc(sizeof(*sd), GFP_KERNEL); 467 if (!bus_entry || !sd) { 468 err = -ENOMEM; 469 goto err_out; 470 } 471 pci_add_resource(&resources, &ioport_resource); 472 pci_add_resource(&resources, &iomem_resource); 473 pci_add_resource(&resources, &busn_res); 474 pcifront_init_sd(sd, domain, bus, pdev); 475 476 pci_lock_rescan_remove(); 477 478 b = pci_scan_root_bus(&pdev->xdev->dev, bus, 479 &pcifront_bus_ops, sd, &resources); 480 if (!b) { 481 dev_err(&pdev->xdev->dev, 482 "Error creating PCI Frontend Bus!\n"); 483 err = -ENOMEM; 484 pci_unlock_rescan_remove(); 485 pci_free_resource_list(&resources); 486 goto err_out; 487 } 488 489 bus_entry->bus = b; 490 491 list_add(&bus_entry->list, &pdev->root_buses); 492 493 /* 494 * pci_scan_root_bus skips devices which do not have a 495 * devfn==0. The pcifront_scan_bus enumerates all devfn. 496 */ 497 err = pcifront_scan_bus(pdev, domain, bus, b); 498 499 /* Claim resources before going "live" with our devices */ 500 pci_walk_bus(b, pcifront_claim_resource, pdev); 501 502 /* Create SysFS and notify udev of the devices. Aka: "going live" */ 503 pci_bus_add_devices(b); 504 505 pci_unlock_rescan_remove(); 506 return err; 507 508err_out: 509 kfree(bus_entry); 510 kfree(sd); 511 512 return err; 513} 514 515static int pcifront_rescan_root(struct pcifront_device *pdev, 516 unsigned int domain, unsigned int bus) 517{ 518 int err; 519 struct pci_bus *b; 520 521 b = pci_find_bus(domain, bus); 522 if (!b) 523 /* If the bus is unknown, create it. */ 524 return pcifront_scan_root(pdev, domain, bus); 525 526 dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n", 527 domain, bus); 528 529 err = pcifront_scan_bus(pdev, domain, bus, b); 530 531 /* Claim resources before going "live" with our devices */ 532 pci_walk_bus(b, pcifront_claim_resource, pdev); 533 534 /* Create SysFS and notify udev of the devices. Aka: "going live" */ 535 pci_bus_add_devices(b); 536 537 return err; 538} 539 540static void free_root_bus_devs(struct pci_bus *bus) 541{ 542 struct pci_dev *dev; 543 544 while (!list_empty(&bus->devices)) { 545 dev = container_of(bus->devices.next, struct pci_dev, 546 bus_list); 547 pci_dbg(dev, "removing device\n"); 548 pci_stop_and_remove_bus_device(dev); 549 } 550} 551 552static void pcifront_free_roots(struct pcifront_device *pdev) 553{ 554 struct pci_bus_entry *bus_entry, *t; 555 556 dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n"); 557 558 pci_lock_rescan_remove(); 559 list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) { 560 list_del(&bus_entry->list); 561 562 free_root_bus_devs(bus_entry->bus); 563 564 kfree(bus_entry->bus->sysdata); 565 566 device_unregister(bus_entry->bus->bridge); 567 pci_remove_bus(bus_entry->bus); 568 569 kfree(bus_entry); 570 } 571 pci_unlock_rescan_remove(); 572} 573 574static pci_ers_result_t pcifront_common_process(int cmd, 575 struct pcifront_device *pdev, 576 pci_channel_state_t state) 577{ 578 struct pci_driver *pdrv; 579 int bus = pdev->sh_info->aer_op.bus; 580 int devfn = pdev->sh_info->aer_op.devfn; 581 int domain = pdev->sh_info->aer_op.domain; 582 struct pci_dev *pcidev; 583 584 dev_dbg(&pdev->xdev->dev, 585 "pcifront AER process: cmd %x (bus:%x, devfn%x)", 586 cmd, bus, devfn); 587 588 pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn); 589 if (!pcidev || !pcidev->dev.driver) { 590 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n"); 591 pci_dev_put(pcidev); 592 return PCI_ERS_RESULT_NONE; 593 } 594 pdrv = to_pci_driver(pcidev->dev.driver); 595 596 if (pdrv->err_handler && pdrv->err_handler->error_detected) { 597 pci_dbg(pcidev, "trying to call AER service\n"); 598 switch (cmd) { 599 case XEN_PCI_OP_aer_detected: 600 return pdrv->err_handler->error_detected(pcidev, state); 601 case XEN_PCI_OP_aer_mmio: 602 return pdrv->err_handler->mmio_enabled(pcidev); 603 case XEN_PCI_OP_aer_slotreset: 604 return pdrv->err_handler->slot_reset(pcidev); 605 case XEN_PCI_OP_aer_resume: 606 pdrv->err_handler->resume(pcidev); 607 return PCI_ERS_RESULT_NONE; 608 default: 609 dev_err(&pdev->xdev->dev, 610 "bad request in aer recovery operation!\n"); 611 } 612 } 613 614 return PCI_ERS_RESULT_NONE; 615} 616 617 618static void pcifront_do_aer(struct work_struct *data) 619{ 620 struct pcifront_device *pdev = 621 container_of(data, struct pcifront_device, op_work); 622 int cmd = pdev->sh_info->aer_op.cmd; 623 pci_channel_state_t state = 624 (pci_channel_state_t)pdev->sh_info->aer_op.err; 625 626 /* 627 * If a pci_conf op is in progress, we have to wait until it is done 628 * before service aer op 629 */ 630 dev_dbg(&pdev->xdev->dev, 631 "pcifront service aer bus %x devfn %x\n", 632 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn); 633 634 pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state); 635 636 /* Post the operation to the guest. */ 637 wmb(); 638 clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags); 639 notify_remote_via_evtchn(pdev->evtchn); 640 641 /*in case of we lost an aer request in four lines time_window*/ 642 smp_mb__before_atomic(); 643 clear_bit(_PDEVB_op_active, &pdev->flags); 644 smp_mb__after_atomic(); 645 646 schedule_pcifront_aer_op(pdev); 647 648} 649 650static irqreturn_t pcifront_handler_aer(int irq, void *dev) 651{ 652 struct pcifront_device *pdev = dev; 653 654 schedule_pcifront_aer_op(pdev); 655 return IRQ_HANDLED; 656} 657static int pcifront_connect_and_init_dma(struct pcifront_device *pdev) 658{ 659 int err = 0; 660 661 spin_lock(&pcifront_dev_lock); 662 663 if (!pcifront_dev) { 664 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n"); 665 pcifront_dev = pdev; 666 } else 667 err = -EEXIST; 668 669 spin_unlock(&pcifront_dev_lock); 670 671 return err; 672} 673 674static void pcifront_disconnect(struct pcifront_device *pdev) 675{ 676 spin_lock(&pcifront_dev_lock); 677 678 if (pdev == pcifront_dev) { 679 dev_info(&pdev->xdev->dev, 680 "Disconnecting PCI Frontend Buses\n"); 681 pcifront_dev = NULL; 682 } 683 684 spin_unlock(&pcifront_dev_lock); 685} 686static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev) 687{ 688 struct pcifront_device *pdev; 689 690 pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL); 691 if (pdev == NULL) 692 goto out; 693 694 if (xenbus_setup_ring(xdev, GFP_KERNEL, (void **)&pdev->sh_info, 1, 695 &pdev->gnt_ref)) { 696 kfree(pdev); 697 pdev = NULL; 698 goto out; 699 } 700 pdev->sh_info->flags = 0; 701 702 /*Flag for registering PV AER handler*/ 703 set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags); 704 705 dev_set_drvdata(&xdev->dev, pdev); 706 pdev->xdev = xdev; 707 708 INIT_LIST_HEAD(&pdev->root_buses); 709 710 spin_lock_init(&pdev->sh_info_lock); 711 712 pdev->evtchn = INVALID_EVTCHN; 713 pdev->irq = -1; 714 715 INIT_WORK(&pdev->op_work, pcifront_do_aer); 716 717 dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n", 718 pdev, pdev->sh_info); 719out: 720 return pdev; 721} 722 723static void free_pdev(struct pcifront_device *pdev) 724{ 725 dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev); 726 727 pcifront_free_roots(pdev); 728 729 cancel_work_sync(&pdev->op_work); 730 731 if (pdev->irq >= 0) 732 unbind_from_irqhandler(pdev->irq, pdev); 733 734 if (pdev->evtchn != INVALID_EVTCHN) 735 xenbus_free_evtchn(pdev->xdev, pdev->evtchn); 736 737 xenbus_teardown_ring((void **)&pdev->sh_info, 1, &pdev->gnt_ref); 738 739 dev_set_drvdata(&pdev->xdev->dev, NULL); 740 741 kfree(pdev); 742} 743 744static int pcifront_publish_info(struct pcifront_device *pdev) 745{ 746 int err = 0; 747 struct xenbus_transaction trans; 748 749 err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn); 750 if (err) 751 goto out; 752 753 err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer, 754 0, "pcifront", pdev); 755 756 if (err < 0) 757 return err; 758 759 pdev->irq = err; 760 761do_publish: 762 err = xenbus_transaction_start(&trans); 763 if (err) { 764 xenbus_dev_fatal(pdev->xdev, err, 765 "Error writing configuration for backend " 766 "(start transaction)"); 767 goto out; 768 } 769 770 err = xenbus_printf(trans, pdev->xdev->nodename, 771 "pci-op-ref", "%u", pdev->gnt_ref); 772 if (!err) 773 err = xenbus_printf(trans, pdev->xdev->nodename, 774 "event-channel", "%u", pdev->evtchn); 775 if (!err) 776 err = xenbus_printf(trans, pdev->xdev->nodename, 777 "magic", XEN_PCI_MAGIC); 778 779 if (err) { 780 xenbus_transaction_end(trans, 1); 781 xenbus_dev_fatal(pdev->xdev, err, 782 "Error writing configuration for backend"); 783 goto out; 784 } else { 785 err = xenbus_transaction_end(trans, 0); 786 if (err == -EAGAIN) 787 goto do_publish; 788 else if (err) { 789 xenbus_dev_fatal(pdev->xdev, err, 790 "Error completing transaction " 791 "for backend"); 792 goto out; 793 } 794 } 795 796 xenbus_switch_state(pdev->xdev, XenbusStateInitialised); 797 798 dev_dbg(&pdev->xdev->dev, "publishing successful!\n"); 799 800out: 801 return err; 802} 803 804static void pcifront_connect(struct pcifront_device *pdev) 805{ 806 int err; 807 int i, num_roots, len; 808 char str[64]; 809 unsigned int domain, bus; 810 811 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, 812 "root_num", "%d", &num_roots); 813 if (err == -ENOENT) { 814 xenbus_dev_error(pdev->xdev, err, 815 "No PCI Roots found, trying 0000:00"); 816 err = pcifront_rescan_root(pdev, 0, 0); 817 if (err) { 818 xenbus_dev_fatal(pdev->xdev, err, 819 "Error scanning PCI root 0000:00"); 820 return; 821 } 822 num_roots = 0; 823 } else if (err != 1) { 824 xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err, 825 "Error reading number of PCI roots"); 826 return; 827 } 828 829 for (i = 0; i < num_roots; i++) { 830 len = snprintf(str, sizeof(str), "root-%d", i); 831 if (unlikely(len >= (sizeof(str) - 1))) 832 return; 833 834 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, 835 "%x:%x", &domain, &bus); 836 if (err != 2) { 837 xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err, 838 "Error reading PCI root %d", i); 839 return; 840 } 841 842 err = pcifront_rescan_root(pdev, domain, bus); 843 if (err) { 844 xenbus_dev_fatal(pdev->xdev, err, 845 "Error scanning PCI root %04x:%02x", 846 domain, bus); 847 return; 848 } 849 } 850 851 xenbus_switch_state(pdev->xdev, XenbusStateConnected); 852} 853 854static void pcifront_try_connect(struct pcifront_device *pdev) 855{ 856 int err; 857 858 /* Only connect once */ 859 if (xenbus_read_driver_state(pdev->xdev->nodename) != 860 XenbusStateInitialised) 861 return; 862 863 err = pcifront_connect_and_init_dma(pdev); 864 if (err && err != -EEXIST) { 865 xenbus_dev_fatal(pdev->xdev, err, 866 "Error setting up PCI Frontend"); 867 return; 868 } 869 870 pcifront_connect(pdev); 871} 872 873static int pcifront_try_disconnect(struct pcifront_device *pdev) 874{ 875 int err = 0; 876 enum xenbus_state prev_state; 877 878 879 prev_state = xenbus_read_driver_state(pdev->xdev->nodename); 880 881 if (prev_state >= XenbusStateClosing) 882 goto out; 883 884 if (prev_state == XenbusStateConnected) { 885 pcifront_free_roots(pdev); 886 pcifront_disconnect(pdev); 887 } 888 889 err = xenbus_switch_state(pdev->xdev, XenbusStateClosed); 890 891out: 892 893 return err; 894} 895 896static void pcifront_attach_devices(struct pcifront_device *pdev) 897{ 898 if (xenbus_read_driver_state(pdev->xdev->nodename) == 899 XenbusStateReconfiguring) 900 pcifront_connect(pdev); 901} 902 903static int pcifront_detach_devices(struct pcifront_device *pdev) 904{ 905 int err = 0; 906 int i, num_devs; 907 enum xenbus_state state; 908 unsigned int domain, bus, slot, func; 909 struct pci_dev *pci_dev; 910 char str[64]; 911 912 state = xenbus_read_driver_state(pdev->xdev->nodename); 913 if (state == XenbusStateInitialised) { 914 dev_dbg(&pdev->xdev->dev, "Handle skipped connect.\n"); 915 /* We missed Connected and need to initialize. */ 916 err = pcifront_connect_and_init_dma(pdev); 917 if (err && err != -EEXIST) { 918 xenbus_dev_fatal(pdev->xdev, err, 919 "Error setting up PCI Frontend"); 920 goto out; 921 } 922 923 goto out_switch_state; 924 } else if (state != XenbusStateConnected) { 925 goto out; 926 } 927 928 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d", 929 &num_devs); 930 if (err != 1) { 931 if (err >= 0) 932 err = -EINVAL; 933 xenbus_dev_fatal(pdev->xdev, err, 934 "Error reading number of PCI devices"); 935 goto out; 936 } 937 938 /* Find devices being detached and remove them. */ 939 for (i = 0; i < num_devs; i++) { 940 int l, state; 941 942 l = snprintf(str, sizeof(str), "state-%d", i); 943 if (unlikely(l >= (sizeof(str) - 1))) { 944 err = -ENOMEM; 945 goto out; 946 } 947 state = xenbus_read_unsigned(pdev->xdev->otherend, str, 948 XenbusStateUnknown); 949 950 if (state != XenbusStateClosing) 951 continue; 952 953 /* Remove device. */ 954 l = snprintf(str, sizeof(str), "vdev-%d", i); 955 if (unlikely(l >= (sizeof(str) - 1))) { 956 err = -ENOMEM; 957 goto out; 958 } 959 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, 960 "%x:%x:%x.%x", &domain, &bus, &slot, &func); 961 if (err != 4) { 962 if (err >= 0) 963 err = -EINVAL; 964 xenbus_dev_fatal(pdev->xdev, err, 965 "Error reading PCI device %d", i); 966 goto out; 967 } 968 969 pci_dev = pci_get_domain_bus_and_slot(domain, bus, 970 PCI_DEVFN(slot, func)); 971 if (!pci_dev) { 972 dev_dbg(&pdev->xdev->dev, 973 "Cannot get PCI device %04x:%02x:%02x.%d\n", 974 domain, bus, slot, func); 975 continue; 976 } 977 pci_lock_rescan_remove(); 978 pci_stop_and_remove_bus_device(pci_dev); 979 pci_dev_put(pci_dev); 980 pci_unlock_rescan_remove(); 981 982 dev_dbg(&pdev->xdev->dev, 983 "PCI device %04x:%02x:%02x.%d removed.\n", 984 domain, bus, slot, func); 985 } 986 987 out_switch_state: 988 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring); 989 990out: 991 return err; 992} 993 994static void pcifront_backend_changed(struct xenbus_device *xdev, 995 enum xenbus_state be_state) 996{ 997 struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev); 998 999 switch (be_state) { 1000 case XenbusStateUnknown: 1001 case XenbusStateInitialising: 1002 case XenbusStateInitWait: 1003 case XenbusStateInitialised: 1004 break; 1005 1006 case XenbusStateConnected: 1007 pcifront_try_connect(pdev); 1008 break; 1009 1010 case XenbusStateClosed: 1011 if (xdev->state == XenbusStateClosed) 1012 break; 1013 fallthrough; /* Missed the backend's CLOSING state */ 1014 case XenbusStateClosing: 1015 dev_warn(&xdev->dev, "backend going away!\n"); 1016 pcifront_try_disconnect(pdev); 1017 break; 1018 1019 case XenbusStateReconfiguring: 1020 pcifront_detach_devices(pdev); 1021 break; 1022 1023 case XenbusStateReconfigured: 1024 pcifront_attach_devices(pdev); 1025 break; 1026 } 1027} 1028 1029static int pcifront_xenbus_probe(struct xenbus_device *xdev, 1030 const struct xenbus_device_id *id) 1031{ 1032 int err = 0; 1033 struct pcifront_device *pdev = alloc_pdev(xdev); 1034 1035 if (pdev == NULL) { 1036 err = -ENOMEM; 1037 xenbus_dev_fatal(xdev, err, 1038 "Error allocating pcifront_device struct"); 1039 goto out; 1040 } 1041 1042 err = pcifront_publish_info(pdev); 1043 if (err) 1044 free_pdev(pdev); 1045 1046out: 1047 return err; 1048} 1049 1050static void pcifront_xenbus_remove(struct xenbus_device *xdev) 1051{ 1052 struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev); 1053 1054 if (pdev) 1055 free_pdev(pdev); 1056} 1057 1058static const struct xenbus_device_id xenpci_ids[] = { 1059 {"pci"}, 1060 {""}, 1061}; 1062 1063static struct xenbus_driver xenpci_driver = { 1064 .name = "pcifront", 1065 .ids = xenpci_ids, 1066 .probe = pcifront_xenbus_probe, 1067 .remove = pcifront_xenbus_remove, 1068 .otherend_changed = pcifront_backend_changed, 1069}; 1070 1071static int __init pcifront_init(void) 1072{ 1073 if (!xen_pv_domain() || xen_initial_domain()) 1074 return -ENODEV; 1075 1076 if (!xen_has_pv_devices()) 1077 return -ENODEV; 1078 1079 pci_frontend_registrar(1 /* enable */); 1080 1081 return xenbus_register_frontend(&xenpci_driver); 1082} 1083 1084static void __exit pcifront_cleanup(void) 1085{ 1086 xenbus_unregister_driver(&xenpci_driver); 1087 pci_frontend_registrar(0 /* disable */); 1088} 1089module_init(pcifront_init); 1090module_exit(pcifront_cleanup); 1091 1092MODULE_DESCRIPTION("Xen PCI passthrough frontend."); 1093MODULE_LICENSE("GPL"); 1094MODULE_ALIAS("xen:pci"); 1095