LXR linux/arch/x86/xen/platform-pci-unplug.c

   1// SPDX-License-Identifier: GPL-2.0
   2
   3/******************************************************************************
   4 * platform-pci-unplug.c
   5 *
   6 * Xen platform PCI device driver
   7 * Copyright (c) 2010, Citrix
   8 */
   9
  10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12#include <linux/init.h>
  13#include <linux/io.h>
  14#include <linux/export.h>
  15
  16#include <xen/xen.h>
  17#include <xen/platform_pci.h>
  18#include "xen-ops.h"
  19
  20#define XEN_PLATFORM_ERR_MAGIC -1
  21#define XEN_PLATFORM_ERR_PROTOCOL -2
  22#define XEN_PLATFORM_ERR_BLACKLIST -3
  23
  24/* store the value of xen_emul_unplug after the unplug is done */
  25static int xen_platform_pci_unplug;
  26static int xen_emul_unplug;
  27
  28static int check_platform_magic(void)
  29{
  30        short magic;
  31        char protocol;
  32
  33        magic = inw(XEN_IOPORT_MAGIC);
  34        if (magic != XEN_IOPORT_MAGIC_VAL) {
  35                pr_err("Xen Platform PCI: unrecognised magic value\n");
  36                return XEN_PLATFORM_ERR_MAGIC;
  37        }
  38
  39        protocol = inb(XEN_IOPORT_PROTOVER);
  40
  41        pr_debug("Xen Platform PCI: I/O protocol version %d\n",
  42                        protocol);
  43
  44        switch (protocol) {
  45        case 1:
  46                outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
  47                outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
  48                if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
  49                        pr_err("Xen Platform: blacklisted by host\n");
  50                        return XEN_PLATFORM_ERR_BLACKLIST;
  51                }
  52                break;
  53        default:
  54                pr_warn("Xen Platform PCI: unknown I/O protocol version\n");
  55                return XEN_PLATFORM_ERR_PROTOCOL;
  56        }
  57
  58        return 0;
  59}
  60
  61bool xen_has_pv_devices(void)
  62{
  63        if (!xen_domain())
  64                return false;
  65
  66        /* PV and PVH domains always have them. */
  67        if (xen_pv_domain() || xen_pvh_domain())
  68                return true;
  69
  70        /* And user has xen_platform_pci=0 set in guest config as
  71         * driver did not modify the value. */
  72        if (xen_platform_pci_unplug == 0)
  73                return false;
  74
  75        if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
  76                return false;
  77
  78        if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
  79                return true;
  80
  81        /* This is an odd one - we are going to run legacy
  82         * and PV drivers at the same time. */
  83        if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
  84                return true;
  85
  86        /* And the caller has to follow with xen_pv_{disk,nic}_devices
  87         * to be certain which driver can load. */
  88        return false;
  89}
  90EXPORT_SYMBOL_GPL(xen_has_pv_devices);
  91
  92static bool __xen_has_pv_device(int state)
  93{
  94        /* HVM domains might or might not */
  95        if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
  96                return true;
  97
  98        return xen_has_pv_devices();
  99}
 100
 101bool xen_has_pv_nic_devices(void)
 102{
 103        return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
 104}
 105EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
 106
 107bool xen_has_pv_disk_devices(void)
 108{
 109        return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
 110                                   XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
 111}
 112EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
 113
 114/*
 115 * This one is odd - it determines whether you want to run PV _and_
 116 * legacy (IDE) drivers together. This combination is only possible
 117 * under HVM.
 118 */
 119bool xen_has_pv_and_legacy_disk_devices(void)
 120{
 121        if (!xen_domain())
 122                return false;
 123
 124        /* N.B. This is only ever used in HVM mode */
 125        if (xen_pv_domain())
 126                return false;
 127
 128        if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
 129                return true;
 130
 131        return false;
 132}
 133EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
 134
 135void xen_unplug_emulated_devices(void)
 136{
 137        int r;
 138
 139        /* PVH guests don't have emulated devices. */
 140        if (xen_pvh_domain())
 141                return;
 142
 143        /* user explicitly requested no unplug */
 144        if (xen_emul_unplug & XEN_UNPLUG_NEVER)
 145                return;
 146        /* check the version of the xen platform PCI device */
 147        r = check_platform_magic();
 148        /* If the version matches enable the Xen platform PCI driver.
 149         * Also enable the Xen platform PCI driver if the host does
 150         * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
 151         * but the user told us that unplugging is unnecessary. */
 152        if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
 153                        (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
 154                return;
 155        /* Set the default value of xen_emul_unplug depending on whether or
 156         * not the Xen PV frontends and the Xen platform PCI driver have
 157         * been compiled for this kernel (modules or built-in are both OK). */
 158        if (!xen_emul_unplug) {
 159                if (xen_must_unplug_nics()) {
 160                        pr_info("Netfront and the Xen platform PCI driver have "
 161                                        "been compiled for this kernel: unplug emulated NICs.\n");
 162                        xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 163                }
 164                if (xen_must_unplug_disks()) {
 165                        pr_info("Blkfront and the Xen platform PCI driver have "
 166                                        "been compiled for this kernel: unplug emulated disks.\n"
 167                                        "You might have to change the root device\n"
 168                                        "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
 169                                        "in your root= kernel command line option\n");
 170                        xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 171                }
 172        }
 173        /* Now unplug the emulated devices */
 174        if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
 175                outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
 176        xen_platform_pci_unplug = xen_emul_unplug;
 177}
 178
 179static int __init parse_xen_emul_unplug(char *arg)
 180{
 181        char *p, *q;
 182        int l;
 183
 184        for (p = arg; p; p = q) {
 185                q = strchr(p, ',');
 186                if (q) {
 187                        l = q - p;
 188                        q++;
 189                } else {
 190                        l = strlen(p);
 191                }
 192                if (!strncmp(p, "all", l))
 193                        xen_emul_unplug |= XEN_UNPLUG_ALL;
 194                else if (!strncmp(p, "ide-disks", l))
 195                        xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 196                else if (!strncmp(p, "aux-ide-disks", l))
 197                        xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
 198                else if (!strncmp(p, "nics", l))
 199                        xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 200                else if (!strncmp(p, "unnecessary", l))
 201                        xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
 202                else if (!strncmp(p, "never", l))
 203                        xen_emul_unplug |= XEN_UNPLUG_NEVER;
 204                else
 205                        pr_warn("unrecognised option '%s' "
 206                                 "in parameter 'xen_emul_unplug'\n", p);
 207        }
 208        return 0;
 209}
 210early_param("xen_emul_unplug", parse_xen_emul_unplug);
 211