1 // SPDX-License-Identifier: GPL-2.0
2
3 /******************************************************************************
4 * platform-pci-unplug.c
5 *
6 * Xen platform PCI device driver
7 * Copyright (c) 2010, Citrix
8 */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/init.h>
13 #include <linux/io.h>
14 #include <linux/export.h>
15
16 #include <xen/xen.h>
17 #include <xen/platform_pci.h>
18 #include "xen-ops.h"
19
20 #define XEN_PLATFORM_ERR_MAGIC -1
21 #define XEN_PLATFORM_ERR_PROTOCOL -2
22 #define XEN_PLATFORM_ERR_BLACKLIST -3
23
24 /* store the value of xen_emul_unplug after the unplug is done */
25 static int xen_platform_pci_unplug;
26 static int xen_emul_unplug;
27
check_platform_magic(void)28 static int check_platform_magic(void)
29 {
30 short magic;
31 char protocol;
32
33 magic = inw(XEN_IOPORT_MAGIC);
34 if (magic != XEN_IOPORT_MAGIC_VAL) {
35 pr_err("Xen Platform PCI: unrecognised magic value\n");
36 return XEN_PLATFORM_ERR_MAGIC;
37 }
38
39 protocol = inb(XEN_IOPORT_PROTOVER);
40
41 pr_debug("Xen Platform PCI: I/O protocol version %d\n",
42 protocol);
43
44 switch (protocol) {
45 case 1:
46 outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
47 outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
48 if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
49 pr_err("Xen Platform: blacklisted by host\n");
50 return XEN_PLATFORM_ERR_BLACKLIST;
51 }
52 break;
53 default:
54 pr_warn("Xen Platform PCI: unknown I/O protocol version\n");
55 return XEN_PLATFORM_ERR_PROTOCOL;
56 }
57
58 return 0;
59 }
60
xen_has_pv_devices(void)61 bool xen_has_pv_devices(void)
62 {
63 if (!xen_domain())
64 return false;
65
66 /* PV and PVH domains always have them. */
67 if (xen_pv_domain() || xen_pvh_domain())
68 return true;
69
70 /* And user has xen_platform_pci=0 set in guest config as
71 * driver did not modify the value. */
72 if (xen_platform_pci_unplug == 0)
73 return false;
74
75 if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
76 return false;
77
78 if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
79 return true;
80
81 /* This is an odd one - we are going to run legacy
82 * and PV drivers at the same time. */
83 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
84 return true;
85
86 /* And the caller has to follow with xen_pv_{disk,nic}_devices
87 * to be certain which driver can load. */
88 return false;
89 }
90 EXPORT_SYMBOL_GPL(xen_has_pv_devices);
91
__xen_has_pv_device(int state)92 static bool __xen_has_pv_device(int state)
93 {
94 /* HVM domains might or might not */
95 if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
96 return true;
97
98 return xen_has_pv_devices();
99 }
100
xen_has_pv_nic_devices(void)101 bool xen_has_pv_nic_devices(void)
102 {
103 return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
104 }
105 EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
106
xen_has_pv_disk_devices(void)107 bool xen_has_pv_disk_devices(void)
108 {
109 return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
110 XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
111 }
112 EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
113
114 /*
115 * This one is odd - it determines whether you want to run PV _and_
116 * legacy (IDE) drivers together. This combination is only possible
117 * under HVM.
118 */
xen_has_pv_and_legacy_disk_devices(void)119 bool xen_has_pv_and_legacy_disk_devices(void)
120 {
121 if (!xen_domain())
122 return false;
123
124 /* N.B. This is only ever used in HVM mode */
125 if (xen_pv_domain())
126 return false;
127
128 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
129 return true;
130
131 return false;
132 }
133 EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
134
xen_unplug_emulated_devices(void)135 void xen_unplug_emulated_devices(void)
136 {
137 int r;
138
139 /* PVH guests don't have emulated devices. */
140 if (xen_pvh_domain())
141 return;
142
143 /* user explicitly requested no unplug */
144 if (xen_emul_unplug & XEN_UNPLUG_NEVER)
145 return;
146 /* check the version of the xen platform PCI device */
147 r = check_platform_magic();
148 /* If the version matches enable the Xen platform PCI driver.
149 * Also enable the Xen platform PCI driver if the host does
150 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
151 * but the user told us that unplugging is unnecessary. */
152 if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
153 (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
154 return;
155 /* Set the default value of xen_emul_unplug depending on whether or
156 * not the Xen PV frontends and the Xen platform PCI driver have
157 * been compiled for this kernel (modules or built-in are both OK). */
158 if (!xen_emul_unplug) {
159 if (xen_must_unplug_nics()) {
160 pr_info("Netfront and the Xen platform PCI driver have "
161 "been compiled for this kernel: unplug emulated NICs.\n");
162 xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
163 }
164 if (xen_must_unplug_disks()) {
165 pr_info("Blkfront and the Xen platform PCI driver have "
166 "been compiled for this kernel: unplug emulated disks.\n"
167 "You might have to change the root device\n"
168 "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
169 "in your root= kernel command line option\n");
170 xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
171 }
172 }
173 /* Now unplug the emulated devices */
174 if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
175 outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
176 xen_platform_pci_unplug = xen_emul_unplug;
177 }
178
parse_xen_emul_unplug(char * arg)179 static int __init parse_xen_emul_unplug(char *arg)
180 {
181 char *p, *q;
182 int l;
183
184 for (p = arg; p; p = q) {
185 q = strchr(p, ',');
186 if (q) {
187 l = q - p;
188 q++;
189 } else {
190 l = strlen(p);
191 }
192 if (!strncmp(p, "all", l))
193 xen_emul_unplug |= XEN_UNPLUG_ALL;
194 else if (!strncmp(p, "ide-disks", l))
195 xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
196 else if (!strncmp(p, "aux-ide-disks", l))
197 xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
198 else if (!strncmp(p, "nics", l))
199 xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
200 else if (!strncmp(p, "unnecessary", l))
201 xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
202 else if (!strncmp(p, "never", l))
203 xen_emul_unplug |= XEN_UNPLUG_NEVER;
204 else
205 pr_warn("unrecognised option '%s' "
206 "in parameter 'xen_emul_unplug'\n", p);
207 }
208 return 0;
209 }
210 early_param("xen_emul_unplug", parse_xen_emul_unplug);
211