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 | |
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 | |
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 | |
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 | |
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 | |
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 | */ |
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 | |
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(value: xen_emul_unplug, XEN_IOPORT_UNPLUG); |
176 | xen_platform_pci_unplug = xen_emul_unplug; |
177 | } |
178 | |
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 | |