diff options
Diffstat (limited to 'drivers/pci/xen-pcifront.c')
| -rw-r--r-- | drivers/pci/xen-pcifront.c | 1104 |
1 files changed, 1104 insertions, 0 deletions
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c new file mode 100644 index 000000000..7378e2f3e --- /dev/null +++ b/drivers/pci/xen-pcifront.c @@ -0,0 +1,1104 @@ +// 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; + + b = pci_find_bus(domain, bus); + if (!b) + /* If the bus is unknown, create it. */ + return pcifront_scan_root(pdev, domain, bus); + + dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n", + 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; + + if (xenbus_setup_ring(xdev, GFP_KERNEL, (void **)&pdev->sh_info, 1, + &pdev->gnt_ref)) { + 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->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); + + xenbus_teardown_ring((void **)&pdev->sh_info, 1, &pdev->gnt_ref); + + 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; + + 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 void pcifront_connect(struct pcifront_device *pdev) +{ + int err; + int i, num_roots, len; + char str[64]; + unsigned int domain, bus; + + 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"); + return; + } + num_roots = 0; + } else if (err != 1) { + xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err, + "Error reading number of PCI roots"); + return; + } + + for (i = 0; i < num_roots; i++) { + len = snprintf(str, sizeof(str), "root-%d", i); + if (unlikely(len >= (sizeof(str) - 1))) + return; + + err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, + "%x:%x", &domain, &bus); + if (err != 2) { + xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err, + "Error reading PCI root %d", i); + return; + } + + err = pcifront_rescan_root(pdev, domain, bus); + if (err) { + xenbus_dev_fatal(pdev->xdev, err, + "Error scanning PCI root %04x:%02x", + domain, bus); + return; + } + } + + xenbus_switch_state(pdev->xdev, XenbusStateConnected); +} + +static void pcifront_try_connect(struct pcifront_device *pdev) +{ + int err; + + /* Only connect once */ + if (xenbus_read_driver_state(pdev->xdev->nodename) != + XenbusStateInitialised) + return; + + err = pcifront_connect_and_init_dma(pdev); + if (err && err != -EEXIST) { + xenbus_dev_fatal(pdev->xdev, err, + "Error setting up PCI Frontend"); + return; + } + + pcifront_connect(pdev); +} + +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 void pcifront_attach_devices(struct pcifront_device *pdev) +{ + if (xenbus_read_driver_state(pdev->xdev->nodename) == + XenbusStateReconfiguring) + pcifront_connect(pdev); +} + +static int pcifront_detach_devices(struct pcifront_device *pdev) +{ + int err = 0; + int i, num_devs; + enum xenbus_state state; + unsigned int domain, bus, slot, func; + struct pci_dev *pci_dev; + char str[64]; + + state = xenbus_read_driver_state(pdev->xdev->nodename); + if (state == XenbusStateInitialised) { + dev_dbg(&pdev->xdev->dev, "Handle skipped connect.\n"); + /* We missed Connected and need to initialize. */ + err = pcifront_connect_and_init_dma(pdev); + if (err && err != -EEXIST) { + xenbus_dev_fatal(pdev->xdev, err, + "Error setting up PCI Frontend"); + goto out; + } + + goto out_switch_state; + } else if (state != 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); + } + + out_switch_state: + 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"); |