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#ifdef CONFIG_XEN_PVHVM
34/* store the value of xen_emul_unplug after the unplug is done */
35static int xen_platform_pci_unplug;
36static int xen_emul_unplug;
37
38static 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
71bool xen_has_pv_devices()
72{
73	if (!xen_domain())
74		return false;
75
76	/* PV domains always have them. */
77	if (xen_pv_domain())
78		return true;
79
80	/* And user has xen_platform_pci=0 set in guest config as
81	 * driver did not modify the value. */
82	if (xen_platform_pci_unplug == 0)
83		return false;
84
85	if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
86		return false;
87
88	if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
89		return true;
90
91	/* This is an odd one - we are going to run legacy
92	 * and PV drivers at the same time. */
93	if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
94		return true;
95
96	/* And the caller has to follow with xen_pv_{disk,nic}_devices
97	 * to be certain which driver can load. */
98	return false;
99}
100EXPORT_SYMBOL_GPL(xen_has_pv_devices);
101
102static bool __xen_has_pv_device(int state)
103{
104	/* HVM domains might or might not */
105	if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
106		return true;
107
108	return xen_has_pv_devices();
109}
110
111bool xen_has_pv_nic_devices(void)
112{
113	return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
114}
115EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
116
117bool xen_has_pv_disk_devices(void)
118{
119	return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
120				   XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
121}
122EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
123
124/*
125 * This one is odd - it determines whether you want to run PV _and_
126 * legacy (IDE) drivers together. This combination is only possible
127 * under HVM.
128 */
129bool xen_has_pv_and_legacy_disk_devices(void)
130{
131	if (!xen_domain())
132		return false;
133
134	/* N.B. This is only ever used in HVM mode */
135	if (xen_pv_domain())
136		return false;
137
138	if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
139		return true;
140
141	return false;
142}
143EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
144
145void xen_unplug_emulated_devices(void)
146{
147	int r;
148
149	/* user explicitly requested no unplug */
150	if (xen_emul_unplug & XEN_UNPLUG_NEVER)
151		return;
152	/* check the version of the xen platform PCI device */
153	r = check_platform_magic();
154	/* If the version matches enable the Xen platform PCI driver.
155	 * Also enable the Xen platform PCI driver if the host does
156	 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
157	 * but the user told us that unplugging is unnecessary. */
158	if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
159			(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
160		return;
161	/* Set the default value of xen_emul_unplug depending on whether or
162	 * not the Xen PV frontends and the Xen platform PCI driver have
163	 * been compiled for this kernel (modules or built-in are both OK). */
164	if (!xen_emul_unplug) {
165		if (xen_must_unplug_nics()) {
166			printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
167					"been compiled for this kernel: unplug emulated NICs.\n");
168			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
169		}
170		if (xen_must_unplug_disks()) {
171			printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
172					"been compiled for this kernel: unplug emulated disks.\n"
173					"You might have to change the root device\n"
174					"from /dev/hd[a-d] to /dev/xvd[a-d]\n"
175					"in your root= kernel command line option\n");
176			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
177		}
178	}
179	/* Now unplug the emulated devices */
180	if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
181		outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
182	xen_platform_pci_unplug = xen_emul_unplug;
183}
184
185static int __init parse_xen_emul_unplug(char *arg)
186{
187	char *p, *q;
188	int l;
189
190	for (p = arg; p; p = q) {
191		q = strchr(p, ',');
192		if (q) {
193			l = q - p;
194			q++;
195		} else {
196			l = strlen(p);
197		}
198		if (!strncmp(p, "all", l))
199			xen_emul_unplug |= XEN_UNPLUG_ALL;
200		else if (!strncmp(p, "ide-disks", l))
201			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
202		else if (!strncmp(p, "aux-ide-disks", l))
203			xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
204		else if (!strncmp(p, "nics", l))
205			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
206		else if (!strncmp(p, "unnecessary", l))
207			xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
208		else if (!strncmp(p, "never", l))
209			xen_emul_unplug |= XEN_UNPLUG_NEVER;
210		else
211			printk(KERN_WARNING "unrecognised option '%s' "
212				 "in parameter 'xen_emul_unplug'\n", p);
213	}
214	return 0;
215}
216early_param("xen_emul_unplug", parse_xen_emul_unplug);
217#endif
218