// SPDX-License-Identifier: GPL-2.0
/*
* Xen PCI Frontend
*
* Author: Ryan Wilson <[email protected]>
*/
#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 <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;
pci_dev_for_each_resource(dev, r, 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);
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 void pcifront_xenbus_remove(struct xenbus_device *xdev)
{
struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
if (pdev)
free_pdev(pdev);
}
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");
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