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
check_platform_magic(void)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
xen_unplug_emulated_devices(void)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
parse_xen_emul_unplug(char * arg)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
144