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

   1 /******************************************************************************
   2  * platform-pci-unplug.c
   3  *
   4  * Xen platform PCI device driver
   5  * Copyright (c) 2010, Citrix
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  18  * Place - Suite 330, Boston, MA 02111-1307 USA.
  19  *
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/io.h>
  24 #include <linux/module.h>
  25
  26 #include <xen/platform_pci.h>
  27 #include "xen-ops.h"
  28
  29 #define XEN_PLATFORM_ERR_MAGIC -1
  30 #define XEN_PLATFORM_ERR_PROTOCOL -2
  31 #define XEN_PLATFORM_ERR_BLACKLIST -3
  32
  33 /* store the value of xen_emul_unplug after the unplug is done */
  34 int xen_platform_pci_unplug;
  35 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
  36 #ifdef CONFIG_XEN_PVHVM
  37 static int xen_emul_unplug;
  38
  39 static int check_platform_magic(void)
  40 {
  41         short magic;
  42         char protocol;
  43
  44         magic = inw(XEN_IOPORT_MAGIC);
  45         if (magic != XEN_IOPORT_MAGIC_VAL) {
  46                 printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
  47                 return XEN_PLATFORM_ERR_MAGIC;
  48         }
  49
  50         protocol = inb(XEN_IOPORT_PROTOVER);
  51
  52         printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n",
  53                         protocol);
  54
  55         switch (protocol) {
  56         case 1:
  57                 outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
  58                 outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
  59                 if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
  60                         printk(KERN_ERR "Xen Platform: blacklisted by host\n");
  61                         return XEN_PLATFORM_ERR_BLACKLIST;
  62                 }
  63                 break;
  64         default:
  65                 printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
  66                 return XEN_PLATFORM_ERR_PROTOCOL;
  67         }
  68
  69         return 0;
  70 }
  71
  72 bool xen_has_pv_devices()
  73 {
  74         if (!xen_domain())
  75                 return false;
  76
  77         /* PV domains always have them. */
  78         if (xen_pv_domain())
  79                 return true;
  80
  81         /* And user has xen_platform_pci=0 set in guest config as
  82          * driver did not modify the value. */
  83         if (xen_platform_pci_unplug == 0)
  84                 return false;
  85
  86         if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
  87                 return false;
  88
  89         if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
  90                 return true;
  91
  92         /* This is an odd one - we are going to run legacy
  93          * and PV drivers at the same time. */
  94         if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
  95                 return true;
  96
  97         /* And the caller has to follow with xen_pv_{disk,nic}_devices
  98          * to be certain which driver can load. */
  99         return false;
 100 }
 101 EXPORT_SYMBOL_GPL(xen_has_pv_devices);
 102
 103 static bool __xen_has_pv_device(int state)
 104 {
 105         /* HVM domains might or might not */
 106         if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
 107                 return true;
 108
 109         return xen_has_pv_devices();
 110 }
 111
 112 bool xen_has_pv_nic_devices(void)
 113 {
 114         return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
 115 }
 116 EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
 117
 118 bool xen_has_pv_disk_devices(void)
 119 {
 120         return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
 121                                    XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
 122 }
 123 EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
 124
 125 /*
 126  * This one is odd - it determines whether you want to run PV _and_
 127  * legacy (IDE) drivers together. This combination is only possible
 128  * under HVM.
 129  */
 130 bool xen_has_pv_and_legacy_disk_devices(void)
 131 {
 132         if (!xen_domain())
 133                 return false;
 134
 135         /* N.B. This is only ever used in HVM mode */
 136         if (xen_pv_domain())
 137                 return false;
 138
 139         if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
 140                 return true;
 141
 142         return false;
 143 }
 144 EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
 145
 146 void xen_unplug_emulated_devices(void)
 147 {
 148         int r;
 149
 150         /* user explicitly requested no unplug */
 151         if (xen_emul_unplug & XEN_UNPLUG_NEVER)
 152                 return;
 153         /* check the version of the xen platform PCI device */
 154         r = check_platform_magic();
 155         /* If the version matches enable the Xen platform PCI driver.
 156          * Also enable the Xen platform PCI driver if the host does
 157          * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
 158          * but the user told us that unplugging is unnecessary. */
 159         if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
 160                         (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
 161                 return;
 162         /* Set the default value of xen_emul_unplug depending on whether or
 163          * not the Xen PV frontends and the Xen platform PCI driver have
 164          * been compiled for this kernel (modules or built-in are both OK). */
 165         if (!xen_emul_unplug) {
 166                 if (xen_must_unplug_nics()) {
 167                         printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
 168                                         "been compiled for this kernel: unplug emulated NICs.\n");
 169                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 170                 }
 171                 if (xen_must_unplug_disks()) {
 172                         printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
 173                                         "been compiled for this kernel: unplug emulated disks.\n"
 174                                         "You might have to change the root device\n"
 175                                         "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
 176                                         "in your root= kernel command line option\n");
 177                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 178                 }
 179         }
 180         /* Now unplug the emulated devices */
 181         if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
 182                 outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
 183         xen_platform_pci_unplug = xen_emul_unplug;
 184 }
 185
 186 static int __init parse_xen_emul_unplug(char *arg)
 187 {
 188         char *p, *q;
 189         int l;
 190
 191         for (p = arg; p; p = q) {
 192                 q = strchr(p, ',');
 193                 if (q) {
 194                         l = q - p;
 195                         q++;
 196                 } else {
 197                         l = strlen(p);
 198                 }
 199                 if (!strncmp(p, "all", l))
 200                         xen_emul_unplug |= XEN_UNPLUG_ALL;
 201                 else if (!strncmp(p, "ide-disks", l))
 202                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 203                 else if (!strncmp(p, "aux-ide-disks", l))
 204                         xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
 205                 else if (!strncmp(p, "nics", l))
 206                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 207                 else if (!strncmp(p, "unnecessary", l))
 208                         xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
 209                 else if (!strncmp(p, "never", l))
 210                         xen_emul_unplug |= XEN_UNPLUG_NEVER;
 211                 else
 212                         printk(KERN_WARNING "unrecognised option '%s' "
 213                                  "in parameter 'xen_emul_unplug'\n", p);
 214         }
 215         return 0;
 216 }
 217 early_param("xen_emul_unplug", parse_xen_emul_unplug);
 218 #endif