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 #ifdef CONFIG_XEN_PVHVM
  34 /* store the value of xen_emul_unplug after the unplug is done */
  35 static int xen_platform_pci_unplug;
  36 static int xen_emul_unplug;
  37
  38 static int check_platform_magic(void)
  39 {
  40         short magic;
  41         char protocol;
  42
  43         magic = inw(XEN_IOPORT_MAGIC);
  44         if (magic != XEN_IOPORT_MAGIC_VAL) {
  45                 printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
  46                 return XEN_PLATFORM_ERR_MAGIC;
  47         }
  48
  49         protocol = inb(XEN_IOPORT_PROTOVER);
  50
  51         printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n",
  52                         protocol);
  53
  54         switch (protocol) {
  55         case 1:
  56                 outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
  57                 outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
  58                 if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
  59                         printk(KERN_ERR "Xen Platform: blacklisted by host\n");
  60                         return XEN_PLATFORM_ERR_BLACKLIST;
  61                 }
  62                 break;
  63         default:
  64                 printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
  65                 return XEN_PLATFORM_ERR_PROTOCOL;
  66         }
  67
  68         return 0;
  69 }
  70
  71 bool xen_has_pv_devices()
  72 {
  73         if (!xen_domain())
  74                 return false;
  75
  76         /* PV domains always have them. */
  77         if (xen_pv_domain())
  78                 return true;
  79
  80         /* And user has xen_platform_pci=0 set in guest config as
  81          * driver did not modify the value. */
  82         if (xen_platform_pci_unplug == 0)
  83                 return false;
  84
  85         if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
  86                 return false;
  87
  88         if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
  89                 return true;
  90
  91         /* This is an odd one - we are going to run legacy
  92          * and PV drivers at the same time. */
  93         if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
  94                 return true;
  95
  96         /* And the caller has to follow with xen_pv_{disk,nic}_devices
  97          * to be certain which driver can load. */
  98         return false;
  99 }
 100 EXPORT_SYMBOL_GPL(xen_has_pv_devices);
 101
 102 static bool __xen_has_pv_device(int state)
 103 {
 104         /* HVM domains might or might not */
 105         if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
 106                 return true;
 107
 108         return xen_has_pv_devices();
 109 }
 110
 111 bool xen_has_pv_nic_devices(void)
 112 {
 113         return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
 114 }
 115 EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
 116
 117 bool xen_has_pv_disk_devices(void)
 118 {
 119         return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
 120                                    XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
 121 }
 122 EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
 123
 124 /*
 125  * This one is odd - it determines whether you want to run PV _and_
 126  * legacy (IDE) drivers together. This combination is only possible
 127  * under HVM.
 128  */
 129 bool xen_has_pv_and_legacy_disk_devices(void)
 130 {
 131         if (!xen_domain())
 132                 return false;
 133
 134         /* N.B. This is only ever used in HVM mode */
 135         if (xen_pv_domain())
 136                 return false;
 137
 138         if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
 139                 return true;
 140
 141         return false;
 142 }
 143 EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
 144
 145 void xen_unplug_emulated_devices(void)
 146 {
 147         int r;
 148
 149         /* user explicitly requested no unplug */
 150         if (xen_emul_unplug & XEN_UNPLUG_NEVER)
 151                 return;
 152         /* check the version of the xen platform PCI device */
 153         r = check_platform_magic();
 154         /* If the version matches enable the Xen platform PCI driver.
 155          * Also enable the Xen platform PCI driver if the host does
 156          * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
 157          * but the user told us that unplugging is unnecessary. */
 158         if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
 159                         (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
 160                 return;
 161         /* Set the default value of xen_emul_unplug depending on whether or
 162          * not the Xen PV frontends and the Xen platform PCI driver have
 163          * been compiled for this kernel (modules or built-in are both OK). */
 164         if (!xen_emul_unplug) {
 165                 if (xen_must_unplug_nics()) {
 166                         printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
 167                                         "been compiled for this kernel: unplug emulated NICs.\n");
 168                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 169                 }
 170                 if (xen_must_unplug_disks()) {
 171                         printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
 172                                         "been compiled for this kernel: unplug emulated disks.\n"
 173                                         "You might have to change the root device\n"
 174                                         "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
 175                                         "in your root= kernel command line option\n");
 176                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 177                 }
 178         }
 179         /* Now unplug the emulated devices */
 180         if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
 181                 outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
 182         xen_platform_pci_unplug = xen_emul_unplug;
 183 }
 184
 185 static int __init parse_xen_emul_unplug(char *arg)
 186 {
 187         char *p, *q;
 188         int l;
 189
 190         for (p = arg; p; p = q) {
 191                 q = strchr(p, ',');
 192                 if (q) {
 193                         l = q - p;
 194                         q++;
 195                 } else {
 196                         l = strlen(p);
 197                 }
 198                 if (!strncmp(p, "all", l))
 199                         xen_emul_unplug |= XEN_UNPLUG_ALL;
 200                 else if (!strncmp(p, "ide-disks", l))
 201                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 202                 else if (!strncmp(p, "aux-ide-disks", l))
 203                         xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
 204                 else if (!strncmp(p, "nics", l))
 205                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 206                 else if (!strncmp(p, "unnecessary", l))
 207                         xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
 208                 else if (!strncmp(p, "never", l))
 209                         xen_emul_unplug |= XEN_UNPLUG_NEVER;
 210                 else
 211                         printk(KERN_WARNING "unrecognised option '%s' "
 212                                  "in parameter 'xen_emul_unplug'\n", p);
 213         }
 214         return 0;
 215 }
 216 early_param("xen_emul_unplug", parse_xen_emul_unplug);
 217 #endif