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