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1// SPDX-License-Identifier: GPL-2.02/*3 * Xen PCI Frontend4 *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 after131 * 2 seconds. It is better to time out too late rather than too early132 * (in the latter case we end up continually re-executing poll() with a133 * 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 we156 * reuse same evtchn with pci_conf backend response. So re-schedule157 * 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_MSI241static 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 else379 xen_pci_frontend = NULL;380};381#else382static 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 prevents417 * 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_DOMAINS452 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#endif461 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 a495 * 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 done628 * before service aer op629 */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 } else667 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