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 /*
69 * Memory ranges available for creating external mappings (foreign or grant
70 * pages for example).
71 */
72 static struct rman unpopulated_mem = {
73 .rm_end = ~0,
74 .rm_type = RMAN_ARRAY,
75 .rm_descr = "Xen scratch memory",
76 };
77
78 static void
xenpv_identify(driver_t * driver,device_t parent)79 xenpv_identify(driver_t *driver, device_t parent)
80 {
81 if (!xen_domain())
82 return;
83
84 /* Make sure there's only one xenpv device. */
85 if (devclass_get_device(devclass_find(driver->name), 0))
86 return;
87
88 /*
89 * The xenpv bus should be the last to attach in order
90 * to properly detect if an ISA bus has already been added.
91 */
92 if (BUS_ADD_CHILD(parent, UINT_MAX, driver->name, 0) == NULL)
93 panic("Unable to attach xenpv bus.");
94 }
95
96 static int
xenpv_probe(device_t dev)97 xenpv_probe(device_t dev)
98 {
99
100 device_set_desc(dev, "Xen PV bus");
101 return (BUS_PROBE_NOWILDCARD);
102 }
103
104 /* Dummy init for arches that don't have a specific implementation. */
105 int __weak_symbol
xen_arch_init_physmem(device_t dev,struct rman * mem)106 xen_arch_init_physmem(device_t dev, struct rman *mem)
107 {
108
109 return (0);
110 }
111
112 static int
xenpv_attach(device_t dev)113 xenpv_attach(device_t dev)
114 {
115 int error = rman_init(&unpopulated_mem);
116
117 if (error != 0)
118 return (error);
119
120 error = xen_arch_init_physmem(dev, &unpopulated_mem);
121 if (error != 0)
122 return (error);
123
124 /*
125 * Let our child drivers identify any child devices that they
126 * can find. Once that is done attach any devices that we
127 * found.
128 */
129 bus_identify_children(dev);
130 bus_attach_children(dev);
131
132 return (0);
133 }
134
135 static int
release_unpopulated_mem(device_t dev,struct resource * res)136 release_unpopulated_mem(device_t dev, struct resource *res)
137 {
138
139 return (rman_is_region_manager(res, &unpopulated_mem) ?
140 rman_release_resource(res) : bus_release_resource(dev, res));
141 }
142
143 static struct resource *
xenpv_alloc_physmem(device_t dev,device_t child,int * res_id,size_t size)144 xenpv_alloc_physmem(device_t dev, device_t child, int *res_id, size_t size)
145 {
146 struct resource *res;
147 vm_paddr_t phys_addr;
148 void *virt_addr;
149 int error;
150 const unsigned int flags = RF_ACTIVE | RF_UNMAPPED |
151 RF_ALIGNMENT_LOG2(PAGE_SHIFT);
152
153 KASSERT((size & PAGE_MASK) == 0, ("unaligned size requested"));
154 size = round_page(size);
155
156 /* Attempt to allocate from arch resource manager. */
157 res = rman_reserve_resource(&unpopulated_mem, 0, ~0, size, flags,
158 child);
159 if (res != NULL) {
160 rman_set_rid(res, *res_id);
161 rman_set_type(res, SYS_RES_MEMORY);
162 } else {
163 static bool warned = false;
164
165 /* Fallback to generic MMIO allocator. */
166 if (__predict_false(!warned)) {
167 warned = true;
168 device_printf(dev,
169 "unable to allocate from arch specific routine, "
170 "fall back to unused memory areas\n");
171 }
172 res = bus_alloc_resource(child, SYS_RES_MEMORY, res_id,
173 LOW_MEM_LIMIT, ~0, size, flags);
174 }
175
176 if (res == NULL) {
177 device_printf(dev,
178 "failed to allocate Xen unpopulated memory\n");
179 return (NULL);
180 }
181
182 phys_addr = rman_get_start(res);
183 error = vm_phys_fictitious_reg_range(phys_addr, phys_addr + size,
184 VM_MEMATTR_XEN);
185 if (error) {
186 int error = release_unpopulated_mem(child, res);
187
188 if (error != 0)
189 device_printf(dev, "failed to release resource: %d\n",
190 error);
191
192 return (NULL);
193 }
194 virt_addr = pmap_mapdev_attr(phys_addr, size, VM_MEMATTR_XEN);
195 KASSERT(virt_addr != NULL, ("Failed to create linear mappings"));
196 rman_set_virtual(res, virt_addr);
197
198 return (res);
199 }
200
201 static int
xenpv_free_physmem(device_t dev,device_t child,int res_id,struct resource * res)202 xenpv_free_physmem(device_t dev, device_t child, int res_id, struct resource *res)
203 {
204 vm_paddr_t phys_addr;
205 void *virt_addr;
206 size_t size;
207
208 phys_addr = rman_get_start(res);
209 size = rman_get_size(res);
210 virt_addr = rman_get_virtual(res);
211
212 pmap_unmapdev(virt_addr, size);
213 vm_phys_fictitious_unreg_range(phys_addr, phys_addr + size);
214
215 return (release_unpopulated_mem(child, res));
216 }
217
218 static device_method_t xenpv_methods[] = {
219 /* Device interface */
220 DEVMETHOD(device_identify, xenpv_identify),
221 DEVMETHOD(device_probe, xenpv_probe),
222 DEVMETHOD(device_attach, xenpv_attach),
223 DEVMETHOD(device_suspend, bus_generic_suspend),
224 DEVMETHOD(device_resume, bus_generic_resume),
225
226 /* Bus interface */
227 DEVMETHOD(bus_add_child, bus_generic_add_child),
228 DEVMETHOD(bus_alloc_resource, bus_generic_alloc_resource),
229 DEVMETHOD(bus_release_resource, bus_generic_release_resource),
230 DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
231 DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
232
233 /* Interface to allocate memory for foreign mappings */
234 DEVMETHOD(xenmem_alloc, xenpv_alloc_physmem),
235 DEVMETHOD(xenmem_free, xenpv_free_physmem),
236
237 DEVMETHOD_END
238 };
239
240 static driver_t xenpv_driver = {
241 "xenpv",
242 xenpv_methods,
243 0,
244 };
245
246 DRIVER_MODULE(xenpv, nexus, xenpv_driver, 0, 0);
247
248 struct resource *
xenmem_alloc(device_t dev,int * res_id,size_t size)249 xenmem_alloc(device_t dev, int *res_id, size_t size)
250 {
251 device_t parent;
252
253 parent = device_get_parent(dev);
254 if (parent == NULL)
255 return (NULL);
256 return (XENMEM_ALLOC(parent, dev, res_id, size));
257 }
258
259 int
xenmem_free(device_t dev,int res_id,struct resource * res)260 xenmem_free(device_t dev, int res_id, struct resource *res)
261 {
262 device_t parent;
263
264 parent = device_get_parent(dev);
265 if (parent == NULL)
266 return (ENXIO);
267 return (XENMEM_FREE(parent, dev, res_id, res));
268 }
269