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
  28 #define XEN_PLATFORM_ERR_MAGIC -1
  29 #define XEN_PLATFORM_ERR_PROTOCOL -2
  30 #define XEN_PLATFORM_ERR_BLACKLIST -3
  31
  32 /* store the value of xen_emul_unplug after the unplug is done */
  33 int xen_platform_pci_unplug;
  34 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
  35 #ifdef CONFIG_XEN_PVHVM
  36 static int xen_emul_unplug;
  37
  38 static int __init 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 void xen_unplug_emulated_devices(void)
  72 {
  73         int r;
  74
  75         /* user explicitly requested no unplug */
  76         if (xen_emul_unplug & XEN_UNPLUG_NEVER)
  77                 return;
  78         /* check the version of the xen platform PCI device */
  79         r = check_platform_magic();
  80         /* If the version matches enable the Xen platform PCI driver.
  81          * Also enable the Xen platform PCI driver if the host does
  82          * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
  83          * but the user told us that unplugging is unnecessary. */
  84         if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
  85                         (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
  86                 return;
  87         /* Set the default value of xen_emul_unplug depending on whether or
  88          * not the Xen PV frontends and the Xen platform PCI driver have
  89          * been compiled for this kernel (modules or built-in are both OK). */
  90         if (!xen_emul_unplug) {
  91                 if (xen_must_unplug_nics()) {
  92                         printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
  93                                         "been compiled for this kernel: unplug emulated NICs.\n");
  94                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
  95                 }
  96                 if (xen_must_unplug_disks()) {
  97                         printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
  98                                         "been compiled for this kernel: unplug emulated disks.\n"
  99                                         "You might have to change the root device\n"
 100                                         "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
 101                                         "in your root= kernel command line option\n");
 102                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 103                 }
 104         }
 105         /* Now unplug the emulated devices */
 106         if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
 107                 outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
 108         xen_platform_pci_unplug = xen_emul_unplug;
 109 }
 110
 111 static int __init parse_xen_emul_unplug(char *arg)
 112 {
 113         char *p, *q;
 114         int l;
 115
 116         for (p = arg; p; p = q) {
 117                 q = strchr(p, ',');
 118                 if (q) {
 119                         l = q - p;
 120                         q++;
 121                 } else {
 122                         l = strlen(p);
 123                 }
 124                 if (!strncmp(p, "all", l))
 125                         xen_emul_unplug |= XEN_UNPLUG_ALL;
 126                 else if (!strncmp(p, "ide-disks", l))
 127                         xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
 128                 else if (!strncmp(p, "aux-ide-disks", l))
 129                         xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
 130                 else if (!strncmp(p, "nics", l))
 131                         xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
 132                 else if (!strncmp(p, "unnecessary", l))
 133                         xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
 134                 else if (!strncmp(p, "never", l))
 135                         xen_emul_unplug |= XEN_UNPLUG_NEVER;
 136                 else
 137                         printk(KERN_WARNING "unrecognised option '%s' "
 138                                  "in parameter 'xen_emul_unplug'\n", p);
 139         }
 140         return 0;
 141 }
 142 early_param("xen_emul_unplug", parse_xen_emul_unplug);
 143 #endif