i86xpv/io/balloon_drv.c

	balloon_drv.c revision 843e19887f64dde75055cf8842fc4db2171eff45
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * A simple wrapper around the balloon kernel thread to allow userland
 * programs access to the balloon status.
 */

#include <sys/types.h>
#include <sys/file.h>
#include <sys/errno.h>
#include <sys/open.h>
#include <sys/cred.h>
#include <sys/conf.h>
#include <sys/stat.h>
#include <sys/modctl.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/hypervisor.h>
#include <sys/sysmacros.h>
#include <sys/balloon_impl.h>

static dev_info_t *balloon_devi;

/*ARGSUSED*/
static int
balloon_getinfo(dev_info_t *devi, ddi_info_cmd_t cmd, void *arg, void **result)
{
    if (getminor((dev_t)arg) != BALLOON_MINOR)
        return (DDI_FAILURE);

    switch (cmd) {
    case DDI_INFO_DEVT2DEVINFO:
        *result = balloon_devi;
        break;
    case DDI_INFO_DEVT2INSTANCE:
        *result = 0;
        break;
    default:
        return (DDI_FAILURE);
    }

    return (DDI_SUCCESS);
}

static int
balloon_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    if (cmd != DDI_ATTACH)
        return (DDI_FAILURE);

    if (ddi_create_minor_node(devi, ddi_get_name(devi), S_IFCHR,
        ddi_get_instance(devi), DDI_PSEUDO, 0) != DDI_SUCCESS)
        return (DDI_FAILURE);

    balloon_devi = devi;
    ddi_report_dev(devi);
    return (DDI_SUCCESS);
}

static int
balloon_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    if (cmd != DDI_DETACH)
        return (DDI_FAILURE);
    ddi_remove_minor_node(devi, NULL);
    balloon_devi = NULL;
    return (DDI_SUCCESS);
}

/*ARGSUSED1*/
static int
balloon_open(dev_t *dev, int flag, int otyp, cred_t *cr)
{
    return (getminor(*dev) == BALLOON_MINOR ? 0 : ENXIO);
}

/*
 * When asked for one of the balloon values, we simply query the balloon thread.
 */
/*ARGSUSED*/
static int
balloon_ioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *cr,
    int *rval_p)
{
    int rval = 0;
    size_t value;

    switch (cmd) {
    case BLN_IOCTL_CURRENT:
    case BLN_IOCTL_TARGET:
    case BLN_IOCTL_LOW:
    case BLN_IOCTL_HIGH:
    case BLN_IOCTL_LIMIT:
        value = balloon_values(cmd);
        if (ddi_copyout((void *)&value, (void *)arg, sizeof (value),
            mode))
            return (EFAULT);
        break;
    default:
        rval = EINVAL;
        break;
    }
    return (rval);
}

static struct cb_ops balloon_cb_ops = {
    balloon_open,
    nulldev,    /* close */
    nodev,      /* strategy */
    nodev,      /* print */
    nodev,      /* dump */
    nodev,      /* read */
    nodev,      /* write */
    balloon_ioctl,  /* ioctl */
    nodev,      /* devmap */
    nodev,      /* mmap */
    nodev,      /* segmap */
    nochpoll,   /* poll */
    ddi_prop_op,
    NULL,
    D_64BIT | D_MP,
    CB_REV,
    NULL,
    NULL
};

static struct dev_ops balloon_dv_ops = {
    DEVO_REV,
    0,
    balloon_getinfo,
    nulldev,    /* identify */
    nulldev,    /* probe */
    balloon_attach,
    balloon_detach,
    nodev,      /* reset */
    &balloon_cb_ops,
    NULL,       /* struct bus_ops */
    NULL        /* power */
};

static struct modldrv modldrv = {
    &mod_driverops,
    "balloon driver 1.1",
    &balloon_dv_ops
};

static struct modlinkage modl = {
    MODREV_1,
    {
        (void *)&modldrv,
        NULL        /* null termination */
    }
};

int
_init(void)
{
    return (mod_install(&modl));
}

int
_fini(void)
{
    return (mod_remove(&modl));
}

int
_info(struct modinfo *modinfo)
{
    return (mod_info(&modl, modinfo));
}