// SPDX-License-Identifier: GPL-2.0 /* * Xen PCI Frontend * * Author: Ryan Wilson <hap9@epoch.ncsc.mil> */ #include <linux/module.h> #include <linux/init.h> #include <linux/mm.h> #include <xen/xenbus.h> #include <xen/events.h> #include <xen/grant_table.h> #include <xen/page.h> #include <linux/spinlock.h> #include <linux/pci.h> #include <linux/msi.h> #include <xen/interface/io/pciif.h> #include <asm/xen/pci.h> #include <linux/interrupt.h> #include <linux/atomic.h> #include <linux/workqueue.h> #include <linux/bitops.h> #include <linux/time.h> #include <linux/ktime.h> #include <linux/swiotlb.h> #include <xen/platform_pci.h> #include <asm/xen/swiotlb-xen.h> #define INVALID_EVTCHN (-1) struct pci_bus_entry { struct list_head list; struct pci_bus *bus; }; #define _PDEVB_op_active (0) #define PDEVB_op_active (1 << (_PDEVB_op_active)) struct pcifront_device { struct xenbus_device *xdev; struct list_head root_buses; int evtchn; grant_ref_t gnt_ref; int irq; /* Lock this when doing any operations in sh_info */ spinlock_t sh_info_lock; struct xen_pci_sharedinfo *sh_info; struct work_struct op_work; unsigned long flags; }; struct pcifront_sd { struct pci_sysdata sd; struct pcifront_device *pdev; }; static inline struct pcifront_device * pcifront_get_pdev(struct pcifront_sd *sd) { return sd->pdev; } static inline void pcifront_init_sd(struct pcifront_sd *sd, unsigned int domain, unsigned int bus, struct pcifront_device *pdev) { /* Because we do not expose that information via XenBus. */ sd->sd.node = first_online_node; sd->sd.domain = domain; sd->pdev = pdev; } static DEFINE_SPINLOCK(pcifront_dev_lock); static struct pcifront_device *pcifront_dev; static int errno_to_pcibios_err(int errno) { switch (errno) { case XEN_PCI_ERR_success: return PCIBIOS_SUCCESSFUL; case XEN_PCI_ERR_dev_not_found: return PCIBIOS_DEVICE_NOT_FOUND; case XEN_PCI_ERR_invalid_offset: case XEN_PCI_ERR_op_failed: return PCIBIOS_BAD_REGISTER_NUMBER; case XEN_PCI_ERR_not_implemented: return PCIBIOS_FUNC_NOT_SUPPORTED; case XEN_PCI_ERR_access_denied: return PCIBIOS_SET_FAILED; } return errno; } static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev) { if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags) && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) { dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n"); schedule_work(&pdev->op_work); } } static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op) { int err = 0; struct xen_pci_op *active_op = &pdev->sh_info->op; unsigned long irq_flags; evtchn_port_t port = pdev->evtchn; unsigned int irq = pdev->irq; s64 ns, ns_timeout; spin_lock_irqsave(&pdev->sh_info_lock, irq_flags); memcpy(active_op, op, sizeof(struct xen_pci_op)); /* Go */ wmb(); set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); notify_remote_via_evtchn(port); /* * We set a poll timeout of 3 seconds but give up on return after * 2 seconds. It is better to time out too late rather than too early * (in the latter case we end up continually re-executing poll() with a * timeout in the past). 1s difference gives plenty of slack for error. */ ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC; xen_clear_irq_pending(irq); while (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)) { xen_poll_irq_timeout(irq, jiffies + 3*HZ); xen_clear_irq_pending(irq); ns = ktime_get_ns(); if (ns > ns_timeout) { dev_err(&pdev->xdev->dev, "pciback not responding!!!\n"); clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); err = XEN_PCI_ERR_dev_not_found; goto out; } } /* * We might lose backend service request since we * reuse same evtchn with pci_conf backend response. So re-schedule * aer pcifront service. */ if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)) { dev_err(&pdev->xdev->dev, "schedule aer pcifront service\n"); schedule_pcifront_aer_op(pdev); } memcpy(op, active_op, sizeof(struct xen_pci_op)); err = op->err; out: spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags); return err; } /* Access to this function is spinlocked in drivers/pci/access.c */ static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val) { int err = 0; struct xen_pci_op op = { .cmd = XEN_PCI_OP_conf_read, .domain = pci_domain_nr(bus), .bus = bus->number, .devfn = devfn, .offset = where, .size = size, }; struct pcifront_sd *sd = bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); dev_dbg(&pdev->xdev->dev, "read dev=%04x:%02x:%02x.%d - offset %x size %d\n", pci_domain_nr(bus), bus->number, PCI_SLOT(devfn), PCI_FUNC(devfn), where, size); err = do_pci_op(pdev, &op); if (likely(!err)) { dev_dbg(&pdev->xdev->dev, "read got back value %x\n", op.value); *val = op.value; } else if (err == -ENODEV) { /* No device here, pretend that it just returned 0 */ err = 0; *val = 0; } return errno_to_pcibios_err(err); } /* Access to this function is spinlocked in drivers/pci/access.c */ static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val) { struct xen_pci_op op = { .cmd = XEN_PCI_OP_conf_write, .domain = pci_domain_nr(bus), .bus = bus->number, .devfn = devfn, .offset = where, .size = size, .value = val, }; struct pcifront_sd *sd = bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); dev_dbg(&pdev->xdev->dev, "write dev=%04x:%02x:%02x.%d - offset %x size %d val %x\n", pci_domain_nr(bus), bus->number, PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val); return errno_to_pcibios_err(do_pci_op(pdev, &op)); } static struct pci_ops pcifront_bus_ops = { .read = pcifront_bus_read, .write = pcifront_bus_write, }; #ifdef CONFIG_PCI_MSI static int pci_frontend_enable_msix(struct pci_dev *dev, int vector[], int nvec) { int err; int i; struct xen_pci_op op = { .cmd = XEN_PCI_OP_enable_msix, .domain = pci_domain_nr(dev->bus), .bus = dev->bus->number, .devfn = dev->devfn, .value = nvec, }; struct pcifront_sd *sd = dev->bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); struct msi_desc *entry; if (nvec > SH_INFO_MAX_VEC) { pci_err(dev, "too many vectors (0x%x) for PCI frontend:" " Increase SH_INFO_MAX_VEC\n", nvec); return -EINVAL; } i = 0; msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) { op.msix_entries[i].entry = entry->msi_index; /* Vector is useless at this point. */ op.msix_entries[i].vector = -1; i++; } err = do_pci_op(pdev, &op); if (likely(!err)) { if (likely(!op.value)) { /* we get the result */ for (i = 0; i < nvec; i++) { if (op.msix_entries[i].vector <= 0) { pci_warn(dev, "MSI-X entry %d is invalid: %d!\n", i, op.msix_entries[i].vector); err = -EINVAL; vector[i] = -1; continue; } vector[i] = op.msix_entries[i].vector; } } else { pr_info("enable msix get value %x\n", op.value); err = op.value; } } else { pci_err(dev, "enable msix get err %x\n", err); } return err; } static void pci_frontend_disable_msix(struct pci_dev *dev) { int err; struct xen_pci_op op = { .cmd = XEN_PCI_OP_disable_msix, .domain = pci_domain_nr(dev->bus), .bus = dev->bus->number, .devfn = dev->devfn, }; struct pcifront_sd *sd = dev->bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); err = do_pci_op(pdev, &op); /* What should do for error ? */ if (err) pci_err(dev, "pci_disable_msix get err %x\n", err); } static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[]) { int err; struct xen_pci_op op = { .cmd = XEN_PCI_OP_enable_msi, .domain = pci_domain_nr(dev->bus), .bus = dev->bus->number, .devfn = dev->devfn, }; struct pcifront_sd *sd = dev->bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); err = do_pci_op(pdev, &op); if (likely(!err)) { vector[0] = op.value; if (op.value <= 0) { pci_warn(dev, "MSI entry is invalid: %d!\n", op.value); err = -EINVAL; vector[0] = -1; } } else { pci_err(dev, "pci frontend enable msi failed for dev " "%x:%x\n", op.bus, op.devfn); err = -EINVAL; } return err; } static void pci_frontend_disable_msi(struct pci_dev *dev) { int err; struct xen_pci_op op = { .cmd = XEN_PCI_OP_disable_msi, .domain = pci_domain_nr(dev->bus), .bus = dev->bus->number, .devfn = dev->devfn, }; struct pcifront_sd *sd = dev->bus->sysdata; struct pcifront_device *pdev = pcifront_get_pdev(sd); err = do_pci_op(pdev, &op); if (err == XEN_PCI_ERR_dev_not_found) { /* XXX No response from backend, what shall we do? */ pr_info("get no response from backend for disable MSI\n"); return; } if (err) /* how can pciback notify us fail? */ pr_info("get fake response from backend\n"); } static struct xen_pci_frontend_ops pci_frontend_ops = { .enable_msi = pci_frontend_enable_msi, .disable_msi = pci_frontend_disable_msi, .enable_msix = pci_frontend_enable_msix, .disable_msix = pci_frontend_disable_msix, }; static void pci_frontend_registrar(int enable) { if (enable) xen_pci_frontend = &pci_frontend_ops; else xen_pci_frontend = NULL; }; #else static inline void pci_frontend_registrar(int enable) { }; #endif /* CONFIG_PCI_MSI */ /* Claim resources for the PCI frontend as-is, backend won't allow changes */ static int pcifront_claim_resource(struct pci_dev *dev, void *data) { struct pcifront_device *pdev = data; int i; struct resource *r; for (i = 0; i < PCI_NUM_RESOURCES; i++) { r = &dev->resource[i]; if (!r->parent && r->start && r->flags) { dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n", pci_name(dev), i); if (pci_claim_resource(dev, i)) { dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! " "Device offline. Try using e820_host=1 in the guest config.\n", pci_name(dev), i); } } } return 0; } static int pcifront_scan_bus(struct pcifront_device *pdev, unsigned int domain, unsigned int bus, struct pci_bus *b) { struct pci_dev *d; unsigned int devfn; /* * Scan the bus for functions and add. * We omit handling of PCI bridge attachment because pciback prevents * bridges from being exported. */ for (devfn = 0; devfn < 0x100; devfn++) { d = pci_get_slot(b, devfn); if (d) { /* Device is already known. */ pci_dev_put(d); continue; } d = pci_scan_single_device(b, devfn); if (d) dev_info(&pdev->xdev->dev, "New device on " "%04x:%02x:%02x.%d found.\n", domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn)); } return 0; } static int pcifront_scan_root(struct pcifront_device *pdev, unsigned int domain, unsigned int bus) { struct pci_bus *b; LIST_HEAD(resources); struct pcifront_sd *sd = NULL; struct pci_bus_entry *bus_entry = NULL; int err = 0; static struct resource busn_res = { .start = 0, .end = 255, .flags = IORESOURCE_BUS, }; #ifndef CONFIG_PCI_DOMAINS if (domain != 0) { dev_err(&pdev->xdev->dev, "PCI Root in non-zero PCI Domain! domain=%d\n", domain); dev_err(&pdev->xdev->dev, "Please compile with CONFIG_PCI_DOMAINS\n"); err = -EINVAL; goto err_out; } #endif dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n", domain, bus); bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL); sd = kzalloc(sizeof(*sd), GFP_KERNEL); if (!bus_entry || !sd) { err = -ENOMEM; goto err_out; } pci_add_resource(&resources, &ioport_resource); pci_add_resource(&resources, &iomem_resource); pci_add_resource(&resources, &busn_res); pcifront_init_sd(sd, domain, bus, pdev); pci_lock_rescan_remove(); b = pci_scan_root_bus(&pdev->xdev->dev, bus, &pcifront_bus_ops, sd, &resources); if (!b) { dev_err(&pdev->xdev->dev, "Error creating PCI Frontend Bus!\n"); err = -ENOMEM; pci_unlock_rescan_remove(); pci_free_resource_list(&resources); goto err_out; } bus_entry->bus = b; list_add(&bus_entry->list, &pdev->root_buses); /* * pci_scan_root_bus skips devices which do not have a * devfn==0. The pcifront_scan_bus enumerates all devfn. */ err = pcifront_scan_bus(pdev, domain, bus, b); /* Claim resources before going "live" with our devices */ pci_walk_bus(b, pcifront_claim_resource, pdev); /* Create SysFS and notify udev of the devices. Aka: "going live" */ pci_bus_add_devices(b); pci_unlock_rescan_remove(); return err; err_out: kfree(bus_entry); kfree(sd); return err; } static int pcifront_rescan_root(struct pcifront_device *pdev, unsigned int domain, unsigned int bus) { int err; struct pci_bus *b; #ifndef CONFIG_PCI_DOMAINS if (domain != 0) { dev_err(&pdev->xdev->dev, "PCI Root in non-zero PCI Domain! domain=%d\n", domain); dev_err(&pdev->xdev->dev, "Please compile with CONFIG_PCI_DOMAINS\n"); return -EINVAL; } #endif dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n", domain, bus); b = pci_find_bus(domain, bus); if (!b) /* If the bus is unknown, create it. */ return pcifront_scan_root(pdev, domain, bus); err = pcifront_scan_bus(pdev, domain, bus, b); /* Claim resources before going "live" with our devices */ pci_walk_bus(b, pcifront_claim_resource, pdev); /* Create SysFS and notify udev of the devices. Aka: "going live" */ pci_bus_add_devices(b); return err; } static void free_root_bus_devs(struct pci_bus *bus) { struct pci_dev *dev; while (!list_empty(&bus->devices)) { dev = container_of(bus->devices.next, struct pci_dev, bus_list); pci_dbg(dev, "removing device\n"); pci_stop_and_remove_bus_device(dev); } } static void pcifront_free_roots(struct pcifront_device *pdev) { struct pci_bus_entry *bus_entry, *t; dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n"); pci_lock_rescan_remove(); list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) { list_del(&bus_entry->list); free_root_bus_devs(bus_entry->bus); kfree(bus_entry->bus->sysdata); device_unregister(bus_entry->bus->bridge); pci_remove_bus(bus_entry->bus); kfree(bus_entry); } pci_unlock_rescan_remove(); } static pci_ers_result_t pcifront_common_process(int cmd, struct pcifront_device *pdev, pci_channel_state_t state) { struct pci_driver *pdrv; int bus = pdev->sh_info->aer_op.bus; int devfn = pdev->sh_info->aer_op.devfn; int domain = pdev->sh_info->aer_op.domain; struct pci_dev *pcidev; dev_dbg(&pdev->xdev->dev, "pcifront AER process: cmd %x (bus:%x, devfn%x)", cmd, bus, devfn); pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn); if (!pcidev || !pcidev->dev.driver) { dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n"); pci_dev_put(pcidev); return PCI_ERS_RESULT_NONE; } pdrv = to_pci_driver(pcidev->dev.driver); if (pdrv->err_handler && pdrv->err_handler->error_detected) { pci_dbg(pcidev, "trying to call AER service\n"); switch (cmd) { case XEN_PCI_OP_aer_detected: return pdrv->err_handler->error_detected(pcidev, state); case XEN_PCI_OP_aer_mmio: return pdrv->err_handler->mmio_enabled(pcidev); case XEN_PCI_OP_aer_slotreset: return pdrv->err_handler->slot_reset(pcidev); case XEN_PCI_OP_aer_resume: pdrv->err_handler->resume(pcidev); return PCI_ERS_RESULT_NONE; default: dev_err(&pdev->xdev->dev, "bad request in aer recovery operation!\n"); } } return PCI_ERS_RESULT_NONE; } static void pcifront_do_aer(struct work_struct *data) { struct pcifront_device *pdev = container_of(data, struct pcifront_device, op_work); int cmd = pdev->sh_info->aer_op.cmd; pci_channel_state_t state = (pci_channel_state_t)pdev->sh_info->aer_op.err; /* * If a pci_conf op is in progress, we have to wait until it is done * before service aer op */ dev_dbg(&pdev->xdev->dev, "pcifront service aer bus %x devfn %x\n", pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn); pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state); /* Post the operation to the guest. */ wmb(); clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags); notify_remote_via_evtchn(pdev->evtchn); /*in case of we lost an aer request in four lines time_window*/ smp_mb__before_atomic(); clear_bit(_PDEVB_op_active, &pdev->flags); smp_mb__after_atomic(); schedule_pcifront_aer_op(pdev); } static irqreturn_t pcifront_handler_aer(int irq, void *dev) { struct pcifront_device *pdev = dev; schedule_pcifront_aer_op(pdev); return IRQ_HANDLED; } static int pcifront_connect_and_init_dma(struct pcifront_device *pdev) { int err = 0; spin_lock(&pcifront_dev_lock); if (!pcifront_dev) { dev_info(&pdev->xdev->dev, "Installing PCI frontend\n"); pcifront_dev = pdev; } else err = -EEXIST; spin_unlock(&pcifront_dev_lock); if (!err && !is_swiotlb_active(&pdev->xdev->dev)) { err = pci_xen_swiotlb_init_late(); if (err) dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n"); } return err; } static void pcifront_disconnect(struct pcifront_device *pdev) { spin_lock(&pcifront_dev_lock); if (pdev == pcifront_dev) { dev_info(&pdev->xdev->dev, "Disconnecting PCI Frontend Buses\n"); pcifront_dev = NULL; } spin_unlock(&pcifront_dev_lock); } static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev) { struct pcifront_device *pdev; pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL); if (pdev == NULL) goto out; pdev->sh_info = (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL); if (pdev->sh_info == NULL) { kfree(pdev); pdev = NULL; goto out; } pdev->sh_info->flags = 0; /*Flag for registering PV AER handler*/ set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags); dev_set_drvdata(&xdev->dev, pdev); pdev->xdev = xdev; INIT_LIST_HEAD(&pdev->root_buses); spin_lock_init(&pdev->sh_info_lock); pdev->evtchn = INVALID_EVTCHN; pdev->gnt_ref = INVALID_GRANT_REF; pdev->irq = -1; INIT_WORK(&pdev->op_work, pcifront_do_aer); dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n", pdev, pdev->sh_info); out: return pdev; } static void free_pdev(struct pcifront_device *pdev) { dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev); pcifront_free_roots(pdev); cancel_work_sync(&pdev->op_work); if (pdev->irq >= 0) unbind_from_irqhandler(pdev->irq, pdev); if (pdev->evtchn != INVALID_EVTCHN) xenbus_free_evtchn(pdev->xdev, pdev->evtchn); if (pdev->gnt_ref != INVALID_GRANT_REF) gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */, (unsigned long)pdev->sh_info); else free_page((unsigned long)pdev->sh_info); dev_set_drvdata(&pdev->xdev->dev, NULL); kfree(pdev); } static int pcifront_publish_info(struct pcifront_device *pdev) { int err = 0; struct xenbus_transaction trans; grant_ref_t gref; err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref); if (err < 0) goto out; pdev->gnt_ref = gref; err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn); if (err) goto out; err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer, 0, "pcifront", pdev); if (err < 0) return err; pdev->irq = err; do_publish: err = xenbus_transaction_start(&trans); if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error writing configuration for backend " "(start transaction)"); goto out; } err = xenbus_printf(trans, pdev->xdev->nodename, "pci-op-ref", "%u", pdev->gnt_ref); if (!err) err = xenbus_printf(trans, pdev->xdev->nodename, "event-channel", "%u", pdev->evtchn); if (!err) err = xenbus_printf(trans, pdev->xdev->nodename, "magic", XEN_PCI_MAGIC); if (err) { xenbus_transaction_end(trans, 1); xenbus_dev_fatal(pdev->xdev, err, "Error writing configuration for backend"); goto out; } else { err = xenbus_transaction_end(trans, 0); if (err == -EAGAIN) goto do_publish; else if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error completing transaction " "for backend"); goto out; } } xenbus_switch_state(pdev->xdev, XenbusStateInitialised); dev_dbg(&pdev->xdev->dev, "publishing successful!\n"); out: return err; } static int pcifront_try_connect(struct pcifront_device *pdev) { int err = -EFAULT; int i, num_roots, len; char str[64]; unsigned int domain, bus; /* Only connect once */ if (xenbus_read_driver_state(pdev->xdev->nodename) != XenbusStateInitialised) goto out; err = pcifront_connect_and_init_dma(pdev); if (err && err != -EEXIST) { xenbus_dev_fatal(pdev->xdev, err, "Error setting up PCI Frontend"); goto out; } err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "root_num", "%d", &num_roots); if (err == -ENOENT) { xenbus_dev_error(pdev->xdev, err, "No PCI Roots found, trying 0000:00"); err = pcifront_scan_root(pdev, 0, 0); if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error scanning PCI root 0000:00"); goto out; } num_roots = 0; } else if (err != 1) { if (err == 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading number of PCI roots"); goto out; } for (i = 0; i < num_roots; i++) { len = snprintf(str, sizeof(str), "root-%d", i); if (unlikely(len >= (sizeof(str) - 1))) { err = -ENOMEM; goto out; } err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%x:%x", &domain, &bus); if (err != 2) { if (err >= 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading PCI root %d", i); goto out; } err = pcifront_scan_root(pdev, domain, bus); if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error scanning PCI root %04x:%02x", domain, bus); goto out; } } err = xenbus_switch_state(pdev->xdev, XenbusStateConnected); out: return err; } static int pcifront_try_disconnect(struct pcifront_device *pdev) { int err = 0; enum xenbus_state prev_state; prev_state = xenbus_read_driver_state(pdev->xdev->nodename); if (prev_state >= XenbusStateClosing) goto out; if (prev_state == XenbusStateConnected) { pcifront_free_roots(pdev); pcifront_disconnect(pdev); } err = xenbus_switch_state(pdev->xdev, XenbusStateClosed); out: return err; } static int pcifront_attach_devices(struct pcifront_device *pdev) { int err = -EFAULT; int i, num_roots, len; unsigned int domain, bus; char str[64]; if (xenbus_read_driver_state(pdev->xdev->nodename) != XenbusStateReconfiguring) goto out; err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "root_num", "%d", &num_roots); if (err == -ENOENT) { xenbus_dev_error(pdev->xdev, err, "No PCI Roots found, trying 0000:00"); err = pcifront_rescan_root(pdev, 0, 0); if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error scanning PCI root 0000:00"); goto out; } num_roots = 0; } else if (err != 1) { if (err == 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading number of PCI roots"); goto out; } for (i = 0; i < num_roots; i++) { len = snprintf(str, sizeof(str), "root-%d", i); if (unlikely(len >= (sizeof(str) - 1))) { err = -ENOMEM; goto out; } err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%x:%x", &domain, &bus); if (err != 2) { if (err >= 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading PCI root %d", i); goto out; } err = pcifront_rescan_root(pdev, domain, bus); if (err) { xenbus_dev_fatal(pdev->xdev, err, "Error scanning PCI root %04x:%02x", domain, bus); goto out; } } xenbus_switch_state(pdev->xdev, XenbusStateConnected); out: return err; } static int pcifront_detach_devices(struct pcifront_device *pdev) { int err = 0; int i, num_devs; unsigned int domain, bus, slot, func; struct pci_dev *pci_dev; char str[64]; if (xenbus_read_driver_state(pdev->xdev->nodename) != XenbusStateConnected) goto out; err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d", &num_devs); if (err != 1) { if (err >= 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading number of PCI devices"); goto out; } /* Find devices being detached and remove them. */ for (i = 0; i < num_devs; i++) { int l, state; l = snprintf(str, sizeof(str), "state-%d", i); if (unlikely(l >= (sizeof(str) - 1))) { err = -ENOMEM; goto out; } state = xenbus_read_unsigned(pdev->xdev->otherend, str, XenbusStateUnknown); if (state != XenbusStateClosing) continue; /* Remove device. */ l = snprintf(str, sizeof(str), "vdev-%d", i); if (unlikely(l >= (sizeof(str) - 1))) { err = -ENOMEM; goto out; } err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%x:%x:%x.%x", &domain, &bus, &slot, &func); if (err != 4) { if (err >= 0) err = -EINVAL; xenbus_dev_fatal(pdev->xdev, err, "Error reading PCI device %d", i); goto out; } pci_dev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(slot, func)); if (!pci_dev) { dev_dbg(&pdev->xdev->dev, "Cannot get PCI device %04x:%02x:%02x.%d\n", domain, bus, slot, func); continue; } pci_lock_rescan_remove(); pci_stop_and_remove_bus_device(pci_dev); pci_dev_put(pci_dev); pci_unlock_rescan_remove(); dev_dbg(&pdev->xdev->dev, "PCI device %04x:%02x:%02x.%d removed.\n", domain, bus, slot, func); } err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring); out: return err; } static void pcifront_backend_changed(struct xenbus_device *xdev, enum xenbus_state be_state) { struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev); switch (be_state) { case XenbusStateUnknown: case XenbusStateInitialising: case XenbusStateInitWait: case XenbusStateInitialised: break; case XenbusStateConnected: pcifront_try_connect(pdev); break; case XenbusStateClosed: if (xdev->state == XenbusStateClosed) break; fallthrough; /* Missed the backend's CLOSING state */ case XenbusStateClosing: dev_warn(&xdev->dev, "backend going away!\n"); pcifront_try_disconnect(pdev); break; case XenbusStateReconfiguring: pcifront_detach_devices(pdev); break; case XenbusStateReconfigured: pcifront_attach_devices(pdev); break; } } static int pcifront_xenbus_probe(struct xenbus_device *xdev, const struct xenbus_device_id *id) { int err = 0; struct pcifront_device *pdev = alloc_pdev(xdev); if (pdev == NULL) { err = -ENOMEM; xenbus_dev_fatal(xdev, err, "Error allocating pcifront_device struct"); goto out; } err = pcifront_publish_info(pdev); if (err) free_pdev(pdev); out: return err; } static int pcifront_xenbus_remove(struct xenbus_device *xdev) { struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev); if (pdev) free_pdev(pdev); return 0; } static const struct xenbus_device_id xenpci_ids[] = { {"pci"}, {""}, }; static struct xenbus_driver xenpci_driver = { .name = "pcifront", .ids = xenpci_ids, .probe = pcifront_xenbus_probe, .remove = pcifront_xenbus_remove, .otherend_changed = pcifront_backend_changed, }; static int __init pcifront_init(void) { if (!xen_pv_domain() || xen_initial_domain()) return -ENODEV; if (!xen_has_pv_devices()) return -ENODEV; pci_frontend_registrar(1 /* enable */); return xenbus_register_frontend(&xenpci_driver); } static void __exit pcifront_cleanup(void) { xenbus_unregister_driver(&xenpci_driver); pci_frontend_registrar(0 /* disable */); } module_init(pcifront_init); module_exit(pcifront_cleanup); MODULE_DESCRIPTION("Xen PCI passthrough frontend."); MODULE_LICENSE("GPL"); MODULE_ALIAS("xen:pci");