xenbus.c File Reference

Xen device bus. More...

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ipxe/malloc.h>
#include <ipxe/device.h>
#include <ipxe/timer.h>
#include <ipxe/nap.h>
#include <ipxe/xen.h>
#include <ipxe/xenstore.h>
#include <ipxe/xenbus.h>

Go to the source code of this file.

Macros
#define	ETIMEDOUT_UNKNOWN   __einfo_error ( EINFO_ETIMEDOUT_UNKNOWN )
#define	EINFO_ETIMEDOUT_UNKNOWN
#define	ETIMEDOUT_INITIALISING   __einfo_error ( EINFO_ETIMEDOUT_INITIALISING )
#define	EINFO_ETIMEDOUT_INITIALISING
#define	ETIMEDOUT_INITWAIT   __einfo_error ( EINFO_ETIMEDOUT_INITWAIT )
#define	EINFO_ETIMEDOUT_INITWAIT
#define	ETIMEDOUT_INITIALISED   __einfo_error ( EINFO_ETIMEDOUT_INITIALISED )
#define	EINFO_ETIMEDOUT_INITIALISED
#define	ETIMEDOUT_CONNECTED   __einfo_error ( EINFO_ETIMEDOUT_CONNECTED )
#define	EINFO_ETIMEDOUT_CONNECTED
#define	ETIMEDOUT_CLOSING   __einfo_error ( EINFO_ETIMEDOUT_CLOSING )
#define	EINFO_ETIMEDOUT_CLOSING
#define	ETIMEDOUT_CLOSED   __einfo_error ( EINFO_ETIMEDOUT_CLOSED )
#define	EINFO_ETIMEDOUT_CLOSED
#define	ETIMEDOUT_RECONFIGURING   __einfo_error ( EINFO_ETIMEDOUT_RECONFIGURING )
#define	EINFO_ETIMEDOUT_RECONFIGURING
#define	ETIMEDOUT_RECONFIGURED   __einfo_error ( EINFO_ETIMEDOUT_RECONFIGURED )
#define	EINFO_ETIMEDOUT_RECONFIGURED
#define	ETIMEDOUT_STATE(state)
#define	XENBUS_BACKEND_TIMEOUT   ( 5 * TICKS_PER_SEC )
	Maximum time to wait for backend to reach a given state, in ticks. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
int	xenbus_set_state (struct xen_device *xendev, int state)
	Set device state. More...
int	xenbus_backend_state (struct xen_device *xendev)
	Get backend state. More...
int	xenbus_backend_wait (struct xen_device *xendev, int state)
	Wait for backend to reach a given state. More...
static struct xen_driver *	xenbus_find_driver (const char *type)
	Find driver for Xen device. More...
static int	xenbus_probe_device (struct xen_hypervisor *xen, struct device *parent, const char *instance, struct xen_driver *driver)
	Probe Xen device. More...
static void	xenbus_remove_device (struct xen_device *xendev)
	Remove Xen device. More...
static int	xenbus_probe_type (struct xen_hypervisor *xen, struct device *parent, const char *type)
	Probe Xen devices of a given type. More...
int	xenbus_probe (struct xen_hypervisor *xen, struct device *parent)
	Probe Xen bus. More...
void	xenbus_remove (struct xen_hypervisor *xen __unused, struct device *parent)
	Remove Xen bus. More...

Detailed Description

Xen device bus.

Definition in file xenbus.c.

Macro Definition Documentation

ETIMEDOUT_UNKNOWN

#define ETIMEDOUT_UNKNOWN   __einfo_error ( EINFO_ETIMEDOUT_UNKNOWN )

Definition at line 45 of file xenbus.c.

EINFO_ETIMEDOUT_UNKNOWN

#define EINFO_ETIMEDOUT_UNKNOWN

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateUnknown,          \
                          "Unknown" )

Definition at line 47 of file xenbus.c.

ETIMEDOUT_INITIALISING

#define ETIMEDOUT_INITIALISING   __einfo_error ( EINFO_ETIMEDOUT_INITIALISING )

Definition at line 50 of file xenbus.c.

EINFO_ETIMEDOUT_INITIALISING

#define EINFO_ETIMEDOUT_INITIALISING

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateInitialising,     \
                          "Initialising" )

Definition at line 52 of file xenbus.c.

ETIMEDOUT_INITWAIT

#define ETIMEDOUT_INITWAIT   __einfo_error ( EINFO_ETIMEDOUT_INITWAIT )

Definition at line 55 of file xenbus.c.

EINFO_ETIMEDOUT_INITWAIT

#define EINFO_ETIMEDOUT_INITWAIT

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateInitWait,         \
                          "InitWait" )

Definition at line 57 of file xenbus.c.

ETIMEDOUT_INITIALISED

#define ETIMEDOUT_INITIALISED   __einfo_error ( EINFO_ETIMEDOUT_INITIALISED )

Definition at line 60 of file xenbus.c.

EINFO_ETIMEDOUT_INITIALISED

#define EINFO_ETIMEDOUT_INITIALISED

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateInitialised,      \
                          "Initialised" )

Definition at line 62 of file xenbus.c.

ETIMEDOUT_CONNECTED

#define ETIMEDOUT_CONNECTED   __einfo_error ( EINFO_ETIMEDOUT_CONNECTED )

Definition at line 65 of file xenbus.c.

EINFO_ETIMEDOUT_CONNECTED

#define EINFO_ETIMEDOUT_CONNECTED

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateConnected,        \
                          "Connected" )

Definition at line 67 of file xenbus.c.

ETIMEDOUT_CLOSING

#define ETIMEDOUT_CLOSING   __einfo_error ( EINFO_ETIMEDOUT_CLOSING )

Definition at line 70 of file xenbus.c.

EINFO_ETIMEDOUT_CLOSING

#define EINFO_ETIMEDOUT_CLOSING

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateClosing,          \
                          "Closing" )

Definition at line 72 of file xenbus.c.

ETIMEDOUT_CLOSED

#define ETIMEDOUT_CLOSED   __einfo_error ( EINFO_ETIMEDOUT_CLOSED )

Definition at line 75 of file xenbus.c.

EINFO_ETIMEDOUT_CLOSED

#define EINFO_ETIMEDOUT_CLOSED

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateClosed,           \
                          "Closed" )

Definition at line 77 of file xenbus.c.

ETIMEDOUT_RECONFIGURING

#define ETIMEDOUT_RECONFIGURING   __einfo_error ( EINFO_ETIMEDOUT_RECONFIGURING )

Definition at line 80 of file xenbus.c.

EINFO_ETIMEDOUT_RECONFIGURING

#define EINFO_ETIMEDOUT_RECONFIGURING

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateReconfiguring,    \
                          "Reconfiguring" )

Definition at line 82 of file xenbus.c.

ETIMEDOUT_RECONFIGURED

#define ETIMEDOUT_RECONFIGURED   __einfo_error ( EINFO_ETIMEDOUT_RECONFIGURED )

Definition at line 85 of file xenbus.c.

EINFO_ETIMEDOUT_RECONFIGURED

#define EINFO_ETIMEDOUT_RECONFIGURED

Value:

__einfo_uniqify ( EINFO_ETIMEDOUT, XenbusStateReconfigured,     \
                          "Reconfigured" )

Definition at line 87 of file xenbus.c.

ETIMEDOUT_STATE

#define ETIMEDOUT_STATE

(

state

)

Value:

EUNIQ ( EINFO_ETIMEDOUT, (state), ETIMEDOUT_UNKNOWN,            \
                ETIMEDOUT_INITIALISING, ETIMEDOUT_INITWAIT,             \
                ETIMEDOUT_INITIALISED, ETIMEDOUT_CONNECTED,             \
                ETIMEDOUT_CLOSING, ETIMEDOUT_CLOSED,                    \
                ETIMEDOUT_RECONFIGURING, ETIMEDOUT_RECONFIGURED )

Definition at line 90 of file xenbus.c.

XENBUS_BACKEND_TIMEOUT

#define XENBUS_BACKEND_TIMEOUT   ( 5 * TICKS_PER_SEC )

Maximum time to wait for backend to reach a given state, in ticks.

Definition at line 98 of file xenbus.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

xenbus_set_state()

int xenbus_set_state	(	struct xen_device *	xendev,
		int	state
	)

Set device state.

Parameters

xendev	Xen device
state	New state

Return values

rc	Return status code

Definition at line 107 of file xenbus.c.

                                                              {
        int rc;

        /* Attempt to set state */
        if ( ( rc = xenstore_write_num ( xendev->xen, state, xendev->key,
                                         "state", NULL ) ) != 0 ) {
                DBGC ( xendev, "XENBUS %s could not set state=\"%d\": %s\n",
                       xendev->key, state, strerror ( rc ) );
                return rc;
        }

        return 0;
}

References DBGC, xen_device::key, NULL, rc, state, strerror(), xen_device::xen, and xenstore_write_num().

Referenced by netfront_open(), and netfront_reset().

xenbus_backend_state()

int xenbus_backend_state

(

struct xen_device *

xendev

)

Get backend state.

Parameters

xendev

Xen device

Return values

state

Backend state, or negative error

Definition at line 127 of file xenbus.c.

                                                       {
        unsigned long state;
        int rc;

        /* Attempt to get backend state */
        if ( ( rc = xenstore_read_num ( xendev->xen, &state, xendev->backend,
                                        "state", NULL ) ) != 0 ) {
                DBGC ( xendev, "XENBUS %s could not read %s/state: %s\n",
                       xendev->key, xendev->backend, strerror ( rc ) );
                return rc;
        }

        return state;
}

References xen_device::backend, DBGC, xen_device::key, NULL, rc, state, strerror(), xen_device::xen, and xenstore_read_num().

Referenced by netfront_reset(), and xenbus_backend_wait().

xenbus_backend_wait()

int xenbus_backend_wait	(	struct xen_device *	xendev,
		int	state
	)

Wait for backend to reach a given state.

Parameters

xendev	Xen device
state	Desired backend state

Return values

rc	Return status code

Definition at line 149 of file xenbus.c.

                                                                 {
        unsigned long started = currticks();
        unsigned long elapsed;
        unsigned int attempts = 0;
        int current_state;
        int rc;

        /* Wait for backend to reach this state */
        do {

                /* Get current backend state */
                current_state = xenbus_backend_state ( xendev );
                if ( current_state < 0 ) {
                        rc = current_state;
                        return rc;
                }
                if ( current_state == state )
                        return 0;

                /* Allow time for backend to react */
                cpu_nap();

                /* XenStore is a very slow interface; any fixed delay
                 * time would be dwarfed by the XenStore access time.
                 * We therefore use wall clock to time out this
                 * operation.
                 */
                elapsed = ( currticks() - started );
                attempts++;

        } while ( elapsed < XENBUS_BACKEND_TIMEOUT );

        /* Construct status code from current backend state */
        rc = -ETIMEDOUT_STATE ( current_state );
        DBGC ( xendev, "XENBUS %s timed out after %d attempts waiting for "
               "%s/state=\"%d\": %s\n", xendev->key, attempts, xendev->backend,
               state, strerror ( rc ) );

        return rc;
}

References xen_device::backend, cpu_nap(), currticks(), DBGC, ETIMEDOUT_STATE, xen_device::key, rc, started, state, strerror(), xenbus_backend_state(), and XENBUS_BACKEND_TIMEOUT.

Referenced by netfront_open(), and netfront_reset().

xenbus_find_driver()

static struct xen_driver* xenbus_find_driver ( const char *  type )

static

Find driver for Xen device.

Parameters

type	Device type

Return values

driver

Driver, or NULL

Definition at line 196 of file xenbus.c.

                                                                   {
        struct xen_driver *xendrv;

        for_each_table_entry ( xendrv, XEN_DRIVERS ) {
                if ( strcmp ( xendrv->type, type ) == 0 )
                        return xendrv;
        }
        return NULL;
}

References for_each_table_entry, NULL, strcmp(), type, xen_driver::type, and XEN_DRIVERS.

Referenced by xenbus_probe_type().

xenbus_probe_device()

static int xenbus_probe_device ( struct xen_hypervisor *  xen, struct device *  parent, const char *  instance, struct xen_driver *  driver  )

static

Probe Xen device.

Parameters

xen	Xen hypervisor
parent	Parent device
instance	Device instance
driver	Device driver

Return values

rc	Return status code

Definition at line 215 of file xenbus.c.

                                                             {
        const char *type = driver->type;
        struct xen_device *xendev;
        size_t key_len;
        int rc;

        /* Allocate and initialise structure */
        key_len = ( 7 /* "device/" */ + strlen ( type ) + 1 /* "/" */ +
                    strlen ( instance ) + 1 /* NUL */ );
        xendev = zalloc ( sizeof ( *xendev ) + key_len );
        if ( ! xendev ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        snprintf ( xendev->dev.name, sizeof ( xendev->dev.name ), "%s/%s",
                   type, instance );
        xendev->dev.desc.bus_type = BUS_TYPE_XEN;
        INIT_LIST_HEAD ( &xendev->dev.children );
        list_add_tail ( &xendev->dev.siblings, &parent->children );
        xendev->dev.parent = parent;
        xendev->xen = xen;
        xendev->key = ( ( void * ) ( xendev + 1 ) );
        snprintf ( xendev->key, key_len, "device/%s/%s", type, instance );
        xendev->driver = driver;
        xendev->dev.driver_name = driver->name;
        DBGC ( xendev, "XENBUS %s has driver \"%s\"\n", xendev->key,
               xendev->driver->name );

        /* Read backend key */
        if ( ( rc = xenstore_read ( xen, &xendev->backend, xendev->key,
                                    "backend", NULL ) ) != 0 ) {
                DBGC ( xendev, "XENBUS %s could not read backend: %s\n",
                       xendev->key, strerror ( rc ) );
                goto err_read_backend;
        }

        /* Read backend domain ID */
        if ( ( rc = xenstore_read_num ( xen, &xendev->backend_id, xendev->key,
                                        "backend-id", NULL ) ) != 0 ) {
                DBGC ( xendev, "XENBUS %s could not read backend-id: %s\n",
                       xendev->key, strerror ( rc ) );
                goto err_read_backend_id;
        }
        DBGC ( xendev, "XENBUS %s backend=\"%s\" in domain %ld\n",
               xendev->key, xendev->backend, xendev->backend_id );

        /* Probe driver */
        if ( ( rc = xendev->driver->probe ( xendev ) ) != 0 ) {
                DBGC ( xendev, "XENBUS could not probe %s: %s\n",
                       xendev->key, strerror ( rc ) );
                goto err_probe;
        }

        return 0;

        xendev->driver->remove ( xendev );
 err_probe:
 err_read_backend_id:
        free ( xendev->backend );
 err_read_backend:
        list_del ( &xendev->dev.siblings );
        free ( xendev );
 err_alloc:
        return rc;
}

References xen_device::backend, xen_device::backend_id, device_description::bus_type, BUS_TYPE_XEN, device::children, DBGC, device::desc, xen_device::dev, xen_device::driver, device::driver_name, ENOMEM, free, INIT_LIST_HEAD, xen_device::key, list_add_tail, list_del, xen_driver::name, device::name, NULL, device::parent, xen_driver::probe, rc, xen_driver::remove, device::siblings, snprintf(), strerror(), strlen(), type, xen_driver::type, xen_device::xen, xenstore_read(), xenstore_read_num(), and zalloc().

Referenced by xenbus_probe_type().

xenbus_remove_device()

static void xenbus_remove_device ( struct xen_device *  xendev )

static

Remove Xen device.

Parameters

xendev

Xen device

Definition at line 288 of file xenbus.c.

                                                               {

        /* Remove device */
        xendev->driver->remove ( xendev );
        free ( xendev->backend );
        list_del ( &xendev->dev.siblings );
        free ( xendev );
}

References xen_device::backend, xen_device::dev, xen_device::driver, free, list_del, xen_driver::remove, and device::siblings.

Referenced by xenbus_remove().

xenbus_probe_type()

static int xenbus_probe_type ( struct xen_hypervisor *  xen, struct device *  parent, const char *  type  )

static

Probe Xen devices of a given type.

Parameters

xen	Xen hypervisor
parent	Parent device
type	Device type

Return values

rc	Return status code

Definition at line 305 of file xenbus.c.

                                                                         {
        struct xen_driver *driver;
        char *children;
        char *child;
        size_t len;
        int rc;

        /* Look for a driver */
        driver = xenbus_find_driver ( type );
        if ( ! driver ) {
                DBGC ( xen, "XENBUS has no driver for \"%s\" devices\n", type );
                /* Not a fatal error */
                rc = 0;
                goto err_no_driver;
        }

        /* Get children of this key */
        if ( ( rc = xenstore_directory ( xen, &children, &len, "device",
                                         type, NULL ) ) != 0 ) {
                DBGC ( xen, "XENBUS could not list \"%s\" devices: %s\n",
                       type, strerror ( rc ) );
                goto err_directory;
        }

        /* Probe each child */
        for ( child = children ; child < ( children + len ) ;
              child += ( strlen ( child ) + 1 /* NUL */ ) ) {
                if ( ( rc = xenbus_probe_device ( xen, parent, child,
                                                  driver ) ) != 0 )
                        goto err_probe_device;
        }

        free ( children );
        return 0;

 err_probe_device:
        free ( children );
 err_directory:
 err_no_driver:
        return rc;
}

References children, DBGC, free, len, NULL, rc, strerror(), strlen(), type, xenbus_find_driver(), xenbus_probe_device(), and xenstore_directory().

Referenced by xenbus_probe().

xenbus_probe()

int xenbus_probe	(	struct xen_hypervisor *	xen,
		struct device *	parent
	)

Probe Xen bus.

Parameters

xen	Xen hypervisor
parent	Parent device

Return values

rc	Return status code

Definition at line 355 of file xenbus.c.

                                                                       {
        char *types;
        char *type;
        size_t len;
        int rc;

        /* Get children of "device" key */
        if ( ( rc = xenstore_directory ( xen, &types, &len, "device",
                                         NULL ) ) != 0 ) {
                DBGC ( xen, "XENBUS could not list device types: %s\n",
                       strerror ( rc ) );
                goto err_directory;
        }

        /* Probe each child type */
        for ( type = types ; type < ( types + len ) ;
              type += ( strlen ( type ) + 1 /* NUL */ ) ) {
                if ( ( rc = xenbus_probe_type ( xen, parent, type ) ) != 0 )
                        goto err_probe_type;
        }

        free ( types );
        return 0;

        xenbus_remove ( xen, parent );
 err_probe_type:
        free ( types );
 err_directory:
        return rc;
}

References DBGC, free, len, NULL, rc, strerror(), strlen(), type, xenbus_probe_type(), xenbus_remove(), and xenstore_directory().

Referenced by hvm_probe().

xenbus_remove()

void xenbus_remove	(	struct xen_hypervisor *xen	__unused,
		struct device *	parent
	)

Remove Xen bus.

Parameters

xen	Xen hypervisor
parent	Parent device

Definition at line 392 of file xenbus.c.

                                             {
        struct xen_device *xendev;
        struct xen_device *tmp;

        /* Remove devices */
        list_for_each_entry_safe ( xendev, tmp, &parent->children,
                                   dev.siblings ) {
                xenbus_remove_device ( xendev );
        }
}

References device::children, xen_device::dev, list_for_each_entry_safe, device::siblings, tmp, and xenbus_remove_device().

Referenced by hvm_probe(), hvm_remove(), and xenbus_probe().