xref: /freebsd/sys/dev/xen/bus/xenpv.c (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1 /*
2  * Copyright (c) 2014 Roger Pau Monné <roger.pau@citrix.com>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/param.h>
28 #include <sys/systm.h>
29 #include <sys/bus.h>
30 #include <sys/kernel.h>
31 #include <sys/module.h>
32 #include <sys/pcpu.h>
33 #include <sys/rman.h>
34 #include <sys/smp.h>
35 #include <sys/limits.h>
36 #include <sys/vmmeter.h>
37 
38 #include <vm/vm.h>
39 #include <vm/vm_page.h>
40 #include <vm/vm_param.h>
41 #include <vm/vm_phys.h>
42 
43 #include <xen/xen-os.h>
44 #include <xen/gnttab.h>
45 
46 #include "xenmem_if.h"
47 
48 /*
49  * Allocate unused physical memory above 4GB in order to map memory
50  * from foreign domains. We use memory starting at 4GB in order to
51  * prevent clashes with MMIO/ACPI regions.
52  *
53  * Since this is not possible on i386 just use any available memory
54  * chunk above 1MB and hope we don't clash with anything else.
55  *
56  * Other architectures better document MMIO regions and drivers more
57  * reliably reserve them.  As such, allow using any unpopulated memory
58  * region.
59  */
60 #ifdef __amd64__
61 #define LOW_MEM_LIMIT	0x100000000ul
62 #elif defined(__i386__)
63 #define LOW_MEM_LIMIT	0x100000ul
64 #else
65 #define LOW_MEM_LIMIT	0
66 #endif
67 
68 static void
69 xenpv_identify(driver_t *driver, device_t parent)
70 {
71 	if (!xen_domain())
72 		return;
73 
74 	/* Make sure there's only one xenpv device. */
75 	if (devclass_get_device(devclass_find(driver->name), 0))
76 		return;
77 
78 	/*
79 	 * The xenpv bus should be the last to attach in order
80 	 * to properly detect if an ISA bus has already been added.
81 	 */
82 	if (BUS_ADD_CHILD(parent, UINT_MAX, driver->name, 0) == NULL)
83 		panic("Unable to attach xenpv bus.");
84 }
85 
86 static int
87 xenpv_probe(device_t dev)
88 {
89 
90 	device_set_desc(dev, "Xen PV bus");
91 	return (BUS_PROBE_NOWILDCARD);
92 }
93 
94 static int
95 xenpv_attach(device_t dev)
96 {
97 	int error;
98 
99 	/*
100 	 * Let our child drivers identify any child devices that they
101 	 * can find.  Once that is done attach any devices that we
102 	 * found.
103 	 */
104 	error = bus_generic_probe(dev);
105 	if (error)
106 		return (error);
107 
108 	error = bus_generic_attach(dev);
109 
110 	return (error);
111 }
112 
113 static struct resource *
114 xenpv_alloc_physmem(device_t dev, device_t child, int *res_id, size_t size)
115 {
116 	struct resource *res;
117 	vm_paddr_t phys_addr;
118 	void *virt_addr;
119 	int error;
120 
121 	res = bus_alloc_resource(child, SYS_RES_MEMORY, res_id, LOW_MEM_LIMIT,
122 	    ~0, size, RF_ACTIVE | RF_UNMAPPED);
123 	if (res == NULL)
124 		return (NULL);
125 
126 	phys_addr = rman_get_start(res);
127 	error = vm_phys_fictitious_reg_range(phys_addr, phys_addr + size,
128 	    VM_MEMATTR_XEN);
129 	if (error) {
130 		bus_release_resource(child, SYS_RES_MEMORY, *res_id, res);
131 		return (NULL);
132 	}
133 	virt_addr = pmap_mapdev_attr(phys_addr, size, VM_MEMATTR_XEN);
134 	KASSERT(virt_addr != NULL, ("Failed to create linear mappings"));
135 	rman_set_virtual(res, virt_addr);
136 
137 	return (res);
138 }
139 
140 static int
141 xenpv_free_physmem(device_t dev, device_t child, int res_id, struct resource *res)
142 {
143 	vm_paddr_t phys_addr;
144 	void *virt_addr;
145 	size_t size;
146 
147 	phys_addr = rman_get_start(res);
148 	size = rman_get_size(res);
149 	virt_addr = rman_get_virtual(res);
150 
151 	pmap_unmapdev(virt_addr, size);
152 	vm_phys_fictitious_unreg_range(phys_addr, phys_addr + size);
153 	return (bus_release_resource(child, SYS_RES_MEMORY, res_id, res));
154 }
155 
156 static device_method_t xenpv_methods[] = {
157 	/* Device interface */
158 	DEVMETHOD(device_identify,		xenpv_identify),
159 	DEVMETHOD(device_probe,			xenpv_probe),
160 	DEVMETHOD(device_attach,		xenpv_attach),
161 	DEVMETHOD(device_suspend,		bus_generic_suspend),
162 	DEVMETHOD(device_resume,		bus_generic_resume),
163 
164 	/* Bus interface */
165 	DEVMETHOD(bus_add_child,		bus_generic_add_child),
166 	DEVMETHOD(bus_alloc_resource,		bus_generic_alloc_resource),
167 	DEVMETHOD(bus_release_resource,		bus_generic_release_resource),
168 	DEVMETHOD(bus_activate_resource,	bus_generic_activate_resource),
169 	DEVMETHOD(bus_deactivate_resource,	bus_generic_deactivate_resource),
170 
171 	/* Interface to allocate memory for foreign mappings */
172 	DEVMETHOD(xenmem_alloc,			xenpv_alloc_physmem),
173 	DEVMETHOD(xenmem_free,			xenpv_free_physmem),
174 
175 	DEVMETHOD_END
176 };
177 
178 static driver_t xenpv_driver = {
179 	"xenpv",
180 	xenpv_methods,
181 	0,
182 };
183 
184 DRIVER_MODULE(xenpv, nexus, xenpv_driver, 0, 0);
185 
186 struct resource *
187 xenmem_alloc(device_t dev, int *res_id, size_t size)
188 {
189 	device_t parent;
190 
191 	parent = device_get_parent(dev);
192 	if (parent == NULL)
193 		return (NULL);
194 	return (XENMEM_ALLOC(parent, dev, res_id, size));
195 }
196 
197 int
198 xenmem_free(device_t dev, int res_id, struct resource *res)
199 {
200 	device_t parent;
201 
202 	parent = device_get_parent(dev);
203 	if (parent == NULL)
204 		return (ENXIO);
205 	return (XENMEM_FREE(parent, dev, res_id, res));
206 }
207