platform-pci-unplug.c

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/******************************************************************************
 * platform-pci-unplug.c
 *
 * Xen platform PCI device driver
 * Copyright (c) 2010, Citrix
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 */

#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>

#include <xen/platform_pci.h>
#include "xen-ops.h"

#define XEN_PLATFORM_ERR_MAGIC -1
#define XEN_PLATFORM_ERR_PROTOCOL -2
#define XEN_PLATFORM_ERR_BLACKLIST -3

/* store the value of xen_emul_unplug after the unplug is done */
int xen_platform_pci_unplug;
EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
#ifdef CONFIG_XEN_PVHVM
static int xen_emul_unplug;

static int check_platform_magic(void)
{
    short magic;
    char protocol;

    magic = inw(XEN_IOPORT_MAGIC);
    if (magic != XEN_IOPORT_MAGIC_VAL) {
        printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
        return XEN_PLATFORM_ERR_MAGIC;
    }

    protocol = inb(XEN_IOPORT_PROTOVER);

    printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n",
            protocol);

    switch (protocol) {
    case 1:
        outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
        outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
        if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
            printk(KERN_ERR "Xen Platform: blacklisted by host\n");
            return XEN_PLATFORM_ERR_BLACKLIST;
        }
        break;
    default:
        printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
        return XEN_PLATFORM_ERR_PROTOCOL;
    }

    return 0;
}

void xen_unplug_emulated_devices(void)
{
    int r;

    /* user explicitly requested no unplug */
    if (xen_emul_unplug & XEN_UNPLUG_NEVER)
        return;
    /* check the version of the xen platform PCI device */
    r = check_platform_magic();
    /* If the version matches enable the Xen platform PCI driver.
     * Also enable the Xen platform PCI driver if the host does
     * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
     * but the user told us that unplugging is unnecessary. */
    if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
            (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
        return;
    /* Set the default value of xen_emul_unplug depending on whether or
     * not the Xen PV frontends and the Xen platform PCI driver have
     * been compiled for this kernel (modules or built-in are both OK). */
    if (!xen_emul_unplug) {
        if (xen_must_unplug_nics()) {
            printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
                    "been compiled for this kernel: unplug emulated NICs.\n");
            xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
        }
        if (xen_must_unplug_disks()) {
            printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
                    "been compiled for this kernel: unplug emulated disks.\n"
                    "You might have to change the root device\n"
                    "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
                    "in your root= kernel command line option\n");
            xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
        }
    }
    /* Now unplug the emulated devices */
    if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
        outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
    xen_platform_pci_unplug = xen_emul_unplug;
}

static int __init parse_xen_emul_unplug(char *arg)
{
    char *p, *q;
    int l;

    for (p = arg; p; p = q) {
        q = strchr(p, ',');
        if (q) {
            l = q - p;
            q++;
        } else {
            l = strlen(p);
        }
        if (!strncmp(p, "all", l))
            xen_emul_unplug |= XEN_UNPLUG_ALL;
        else if (!strncmp(p, "ide-disks", l))
            xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
        else if (!strncmp(p, "aux-ide-disks", l))
            xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
        else if (!strncmp(p, "nics", l))
            xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
        else if (!strncmp(p, "unnecessary", l))
            xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
        else if (!strncmp(p, "never", l))
            xen_emul_unplug |= XEN_UNPLUG_NEVER;
        else
            printk(KERN_WARNING "unrecognised option '%s' "
                 "in parameter 'xen_emul_unplug'\n", p);
    }
    return 0;
}
early_param("xen_emul_unplug", parse_xen_emul_unplug);
#endif