- 根目录:
- drivers
- xen
- xen-pciback
- xenbus.c
/*
* PCI Backend Xenbus Setup - handles setup with frontend and xend
*
* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <asm/xen/pci.h>
#include "pciback.h"
#define INVALID_EVTCHN_IRQ (-1)
struct workqueue_struct *xen_pcibk_wq;
static bool __read_mostly passthrough;
module_param(passthrough, bool, S_IRUGO);
MODULE_PARM_DESC(passthrough,
"Option to specify how to export PCI topology to guest:\n"\
" 0 - (default) Hide the true PCI topology and makes the frontend\n"\
" there is a single PCI bus with only the exported devices on it.\n"\
" For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
" while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
" 1 - Passthrough provides a real view of the PCI topology to the\n"\
" frontend (for example, a device at 06:01.b will still appear at\n"\
" 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
" exposed PCI devices to its driver domains. This may be required\n"\
" for drivers which depend on finding their hardward in certain\n"\
" bus/slot locations.");
static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
{
struct xen_pcibk_device *pdev;
pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
if (pdev == NULL)
goto out;
dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
pdev->xdev = xdev;
dev_set_drvdata(&xdev->dev, pdev);
mutex_init(&pdev->dev_lock);
pdev->sh_info = NULL;
pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
pdev->be_watching = 0;
INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
if (xen_pcibk_init_devices(pdev)) {
kfree(pdev);
pdev = NULL;
}
out:
return pdev;
}
static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
{
mutex_lock(&pdev->dev_lock);
/* Ensure the guest can't trigger our handler before removing devices */
if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
unbind_from_irqhandler(pdev->evtchn_irq, pdev);
pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
}
/* If the driver domain started an op, make sure we complete it
* before releasing the shared memory */
/* Note, the workqueue does not use spinlocks at all.*/
flush_workqueue(xen_pcibk_wq);
if (pdev->sh_info != NULL) {
xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
pdev->sh_info = NULL;
}
mutex_unlock(&pdev->dev_lock);
}
static void free_pdev(struct xen_pcibk_device *pdev)
{
if (pdev->be_watching) {
unregister_xenbus_watch(&pdev->be_watch);
pdev->be_watching = 0;
}
xen_pcibk_disconnect(pdev);
/* N.B. This calls pcistub_put_pci_dev which does the FLR on all
* of the PCIe devices. */
xen_pcibk_release_devices(pdev);
dev_set_drvdata(&pdev->xdev->dev, NULL);
pdev->xdev = NULL;
kfree(pdev);
}
static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
int remote_evtchn)
{
int err = 0;
void *vaddr;
dev_dbg(&pdev->xdev->dev,
"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
gnt_ref, remote_evtchn);
err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error mapping other domain page in ours.");
goto out;
}
pdev->sh_info = vaddr;
err = bind_interdomain_evtchn_to_irqhandler(
pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
0, DRV_NAME, pdev);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error binding event channel to IRQ");
goto out;
}
pdev->evtchn_irq = err;
err = 0;
dev_dbg(&pdev->xdev->dev, "Attached!\n");
out:
return err;
}
static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
{
int err = 0;
int gnt_ref, remote_evtchn;
char *magic = NULL;
mutex_lock(&pdev->dev_lock);
/* Make sure we only do this setup once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateInitialised)
goto out;
/* Wait for frontend to state that it has published the configuration */
if (xenbus_read_driver_state(pdev->xdev->otherend) !=
XenbusStateInitialised)
goto out;
dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
"pci-op-ref", "%u", &gnt_ref,
"event-channel", "%u", &remote_evtchn,
"magic", NULL, &magic, NULL);
if (err) {
/* If configuration didn't get read correctly, wait longer */
xenbus_dev_fatal(pdev->xdev, err,
"Error reading configuration from frontend");
goto out;
}
if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
xenbus_dev_fatal(pdev->xdev, -EFAULT,
"version mismatch (%s/%s) with pcifront - "
"halting " DRV_NAME,
magic, XEN_PCI_MAGIC);
err = -EFAULT;
goto out;
}
err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
if (err)
goto out;
dev_dbg(&pdev->xdev->dev, "Connecting...\n");
err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
if (err)
xenbus_dev_fatal(pdev->xdev, err,
"Error switching to connected state!");
dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
out:
mutex_unlock(&pdev->dev_lock);
kfree(magic);
return err;
}
static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
unsigned int domain, unsigned int bus,
unsigned int devfn, unsigned int devid)
{
int err;
int len;
char str[64];
len = snprintf(str, sizeof(str), "vdev-%d", devid);
if (unlikely(len >= (sizeof(str) - 1))) {
err = -ENOMEM;
goto out;
}
/* Note: The PV protocol uses %02x, don't change it */
err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
"%04x:%02x:%02x.%02x", domain, bus,
PCI_SLOT(devfn), PCI_FUNC(devfn));
out:
return err;
}
static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
int domain, int bus, int slot, int func,
int devid)
{
struct pci_dev *dev;
int err = 0;
dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
domain, bus, slot, func);
dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
if (!dev) {
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Couldn't locate PCI device "
"(%04x:%02x:%02x.%d)! "
"perhaps already in-use?",
domain, bus, slot, func);
goto out;
}
err = xen_pcibk_add_pci_dev(pdev, dev, devid,
xen_pcibk_publish_pci_dev);
if (err)
goto out;
dev_info(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
if (xen_register_device_domain_owner(dev,
pdev->xdev->otherend_id) != 0) {
dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
xen_find_device_domain_owner(dev));
xen_unregister_device_domain_owner(dev);
xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
}
/* TODO: It'd be nice to export a bridge and have all of its children
* get exported with it. This may be best done in xend (which will
* have to calculate resource usage anyway) but we probably want to
* put something in here to ensure that if a bridge gets given to a
* driver domain, that all devices under that bridge are not given
* to other driver domains (as he who controls the bridge can disable
* it and stop the other devices from working).
*/
out:
return err;
}
static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
int domain, int bus, int slot, int func)
{
int err = 0;
struct pci_dev *dev;
dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
domain, bus, slot, func);
dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
if (!dev) {
err = -EINVAL;
dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
"(%04x:%02x:%02x.%d)! not owned by this domain\n",
domain, bus, slot, func);
goto out;
}
dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
xen_unregister_device_domain_owner(dev);
/* N.B. This ends up calling pcistub_put_pci_dev which ends up
* doing the FLR. */
xen_pcibk_release_pci_dev(pdev, dev, true /* use the lock. */);
out:
return err;
}
static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
unsigned int domain, unsigned int bus)
{
unsigned int d, b;
int i, root_num, len, err;
char str[64];
dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
"root_num", "%d", &root_num);
if (err == 0 || err == -ENOENT)
root_num = 0;
else if (err < 0)
goto out;
/* Verify that we haven't already published this pci root */
for (i = 0; i < root_num; 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->nodename,
str, "%x:%x", &d, &b);
if (err < 0)
goto out;
if (err != 2) {
err = -EINVAL;
goto out;
}
if (d == domain && b == bus) {
err = 0;
goto out;
}
}
len = snprintf(str, sizeof(str), "root-%d", root_num);
if (unlikely(len >= (sizeof(str) - 1))) {
err = -ENOMEM;
goto out;
}
dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
root_num, domain, bus);
err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
"%04x:%02x", domain, bus);
if (err)
goto out;
err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
"root_num", "%d", (root_num + 1));
out:
return err;
}
static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
{
int err = 0;
int num_devs;
int domain, bus, slot, func;
int substate;
int i, len;
char state_str[64];
char dev_str[64];
dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
mutex_lock(&pdev->dev_lock);
/* Make sure we only reconfigure once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateReconfiguring)
goto out;
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
&num_devs);
if (err != 1) {
if (err >= 0)
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Error reading number of devices");
goto out;
}
for (i = 0; i < num_devs; i++) {
len = snprintf(state_str, sizeof(state_str), "state-%d", i);
if (unlikely(len >= (sizeof(state_str) - 1))) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"String overflow while reading "
"configuration");
goto out;
}
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
"%d", &substate);
if (err != 1)
substate = XenbusStateUnknown;
switch (substate) {
case XenbusStateInitialising:
dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
if (unlikely(len >= (sizeof(dev_str) - 1))) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"String overflow while "
"reading configuration");
goto out;
}
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
dev_str, "%x:%x:%x.%x",
&domain, &bus, &slot, &func);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error reading device "
"configuration");
goto out;
}
if (err != 4) {
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Error parsing pci device "
"configuration");
goto out;
}
err = xen_pcibk_export_device(pdev, domain, bus, slot,
func, i);
if (err)
goto out;
/* Publish pci roots. */
err = xen_pcibk_publish_pci_roots(pdev,
xen_pcibk_publish_pci_root);
if (err) {
xenbus_dev_fatal(pdev->xdev, err,
"Error while publish PCI root"
"buses for frontend");
goto out;
}
err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
state_str, "%d",
XenbusStateInitialised);
if (err) {
xenbus_dev_fatal(pdev->xdev, err,
"Error switching substate of "
"dev-%d\n", i);
goto out;
}
break;
case XenbusStateClosing:
dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
if (unlikely(len >= (sizeof(dev_str) - 1))) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"String overflow while "
"reading configuration");
goto out;
}
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
dev_str, "%x:%x:%x.%x",
&domain, &bus, &slot, &func);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error reading device "
"configuration");
goto out;
}
if (err != 4) {
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Error parsing pci device "
"configuration");
goto out;
}
err = xen_pcibk_remove_device(pdev, domain, bus, slot,
func);
if (err)
goto out;
/* TODO: If at some point we implement support for pci
* root hot-remove on pcifront side, we'll need to
* remove unnecessary xenstore nodes of pci roots here.
*/
break;
default:
break;
}
}
err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
if (err) {
xenbus_dev_fatal(pdev->xdev, err,
"Error switching to reconfigured state!");
goto out;
}
out:
mutex_unlock(&pdev->dev_lock);
return 0;
}
static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
enum xenbus_state fe_state)
{
struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
switch (fe_state) {
case XenbusStateInitialised:
xen_pcibk_attach(pdev);
break;
case XenbusStateReconfiguring:
xen_pcibk_reconfigure(pdev);
break;
case XenbusStateConnected:
/* pcifront switched its state from reconfiguring to connected.
* Then switch to connected state.
*/
xenbus_switch_state(xdev, XenbusStateConnected);
break;
case XenbusStateClosing:
xen_pcibk_disconnect(pdev);
xenbus_switch_state(xdev, XenbusStateClosing);
break;
case XenbusStateClosed:
xen_pcibk_disconnect(pdev);
xenbus_switch_state(xdev, XenbusStateClosed);
if (xenbus_dev_is_online(xdev))
break;
/* fall through if not online */
case XenbusStateUnknown:
dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
device_unregister(&xdev->dev);
break;
default:
break;
}
}
static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
{
/* Get configuration from xend (if available now) */
int domain, bus, slot, func;
int err = 0;
int i, num_devs;
char dev_str[64];
char state_str[64];
mutex_lock(&pdev->dev_lock);
/* It's possible we could get the call to setup twice, so make sure
* we're not already connected.
*/
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateInitWait)
goto out;
dev_dbg(&pdev->xdev->dev, "getting be setup\n");
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
&num_devs);
if (err != 1) {
if (err >= 0)
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Error reading number of devices");
goto out;
}
for (i = 0; i < num_devs; i++) {
int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
if (unlikely(l >= (sizeof(dev_str) - 1))) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"String overflow while reading "
"configuration");
goto out;
}
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
"%x:%x:%x.%x", &domain, &bus, &slot, &func);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error reading device configuration");
goto out;
}
if (err != 4) {
err = -EINVAL;
xenbus_dev_fatal(pdev->xdev, err,
"Error parsing pci device "
"configuration");
goto out;
}
err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
if (err)
goto out;
/* Switch substate of this device. */
l = snprintf(state_str, sizeof(state_str), "state-%d", i);
if (unlikely(l >= (sizeof(state_str) - 1))) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"String overflow while reading "
"configuration");
goto out;
}
err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
"%d", XenbusStateInitialised);
if (err) {
xenbus_dev_fatal(pdev->xdev, err, "Error switching "
"substate of dev-%d\n", i);
goto out;
}
}
err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
if (err) {
xenbus_dev_fatal(pdev->xdev, err,
"Error while publish PCI root buses "
"for frontend");
goto out;
}
err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
if (err)
xenbus_dev_fatal(pdev->xdev, err,
"Error switching to initialised state!");
out:
mutex_unlock(&pdev->dev_lock);
if (!err)
/* see if pcifront is already configured (if not, we'll wait) */
xen_pcibk_attach(pdev);
return err;
}
static void xen_pcibk_be_watch(struct xenbus_watch *watch,
const char **vec, unsigned int len)
{
struct xen_pcibk_device *pdev =
container_of(watch, struct xen_pcibk_device, be_watch);
switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
case XenbusStateInitWait:
xen_pcibk_setup_backend(pdev);
break;
default:
break;
}
}
static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
int err = 0;
struct xen_pcibk_device *pdev = alloc_pdev(dev);
if (pdev == NULL) {
err = -ENOMEM;
xenbus_dev_fatal(dev, err,
"Error allocating xen_pcibk_device struct");
goto out;
}
/* wait for xend to configure us */
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto out;
/* watch the backend node for backend configuration information */
err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
xen_pcibk_be_watch);
if (err)
goto out;
pdev->be_watching = 1;
/* We need to force a call to our callback here in case
* xend already configured us!
*/
xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
out:
return err;
}
static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
{
struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
if (pdev != NULL)
free_pdev(pdev);
return 0;
}
static const struct xenbus_device_id xen_pcibk_ids[] = {
{"pci"},
{""},
};
static struct xenbus_driver xen_pcibk_driver = {
.name = DRV_NAME,
.ids = xen_pcibk_ids,
.probe = xen_pcibk_xenbus_probe,
.remove = xen_pcibk_xenbus_remove,
.otherend_changed = xen_pcibk_frontend_changed,
};
const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
int __init xen_pcibk_xenbus_register(void)
{
xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
if (!xen_pcibk_wq) {
pr_err("%s: create xen_pciback_workqueue failed\n", __func__);
return -EFAULT;
}
xen_pcibk_backend = &xen_pcibk_vpci_backend;
if (passthrough)
xen_pcibk_backend = &xen_pcibk_passthrough_backend;
pr_info("backend is %s\n", xen_pcibk_backend->name);
return xenbus_register_backend(&xen_pcibk_driver);
}
void __exit xen_pcibk_xenbus_unregister(void)
{
destroy_workqueue(xen_pcibk_wq);
xenbus_unregister_driver(&xen_pcibk_driver);
}