xref: /qemu/backends/hostmem.c (revision 7609ffb9191e3fc473203f4bd58b934161eab358) 
1 /*
2  * QEMU Host Memory Backend
3  *
4  * Copyright (C) 2013-2014 Red Hat Inc
5  *
6  * Authors:
7  *   Igor Mammedov <imammedo@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  */
12 #include "qemu/osdep.h"
13 #include "sysemu/hostmem.h"
14 #include "hw/boards.h"
15 #include "qapi/error.h"
16 #include "qapi/visitor.h"
17 #include "qapi-types.h"
18 #include "qapi-visit.h"
19 #include "qemu/config-file.h"
20 #include "qom/object_interfaces.h"
21 
22 #ifdef CONFIG_NUMA
23 #include <numaif.h>
24 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
25 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
26 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
27 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
28 #endif
29 
30 static void
31 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
32                              void *opaque, Error **errp)
33 {
34     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
35     uint64_t value = backend->size;
36 
37     visit_type_size(v, name, &value, errp);
38 }
39 
40 static void
41 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
42                              void *opaque, Error **errp)
43 {
44     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
45     Error *local_err = NULL;
46     uint64_t value;
47 
48     if (memory_region_size(&backend->mr)) {
49         error_setg(&local_err, "cannot change property value");
50         goto out;
51     }
52 
53     visit_type_size(v, name, &value, &local_err);
54     if (local_err) {
55         goto out;
56     }
57     if (!value) {
58         error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
59                    PRIu64 "'", object_get_typename(obj), name, value);
60         goto out;
61     }
62     backend->size = value;
63 out:
64     error_propagate(errp, local_err);
65 }
66 
67 static void
68 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
69                                    void *opaque, Error **errp)
70 {
71     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
72     uint16List *host_nodes = NULL;
73     uint16List **node = &host_nodes;
74     unsigned long value;
75 
76     value = find_first_bit(backend->host_nodes, MAX_NODES);
77     if (value == MAX_NODES) {
78         return;
79     }
80 
81     *node = g_malloc0(sizeof(**node));
82     (*node)->value = value;
83     node = &(*node)->next;
84 
85     do {
86         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
87         if (value == MAX_NODES) {
88             break;
89         }
90 
91         *node = g_malloc0(sizeof(**node));
92         (*node)->value = value;
93         node = &(*node)->next;
94     } while (true);
95 
96     visit_type_uint16List(v, name, &host_nodes, errp);
97 }
98 
99 static void
100 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
101                                    void *opaque, Error **errp)
102 {
103 #ifdef CONFIG_NUMA
104     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
105     uint16List *l = NULL;
106 
107     visit_type_uint16List(v, name, &l, errp);
108 
109     while (l) {
110         bitmap_set(backend->host_nodes, l->value, 1);
111         l = l->next;
112     }
113 #else
114     error_setg(errp, "NUMA node binding are not supported by this QEMU");
115 #endif
116 }
117 
118 static int
119 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
120 {
121     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
122     return backend->policy;
123 }
124 
125 static void
126 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
127 {
128     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
129     backend->policy = policy;
130 
131 #ifndef CONFIG_NUMA
132     if (policy != HOST_MEM_POLICY_DEFAULT) {
133         error_setg(errp, "NUMA policies are not supported by this QEMU");
134     }
135 #endif
136 }
137 
138 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
139 {
140     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
141 
142     return backend->merge;
143 }
144 
145 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
146 {
147     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
148 
149     if (!memory_region_size(&backend->mr)) {
150         backend->merge = value;
151         return;
152     }
153 
154     if (value != backend->merge) {
155         void *ptr = memory_region_get_ram_ptr(&backend->mr);
156         uint64_t sz = memory_region_size(&backend->mr);
157 
158         qemu_madvise(ptr, sz,
159                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
160         backend->merge = value;
161     }
162 }
163 
164 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
165 {
166     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
167 
168     return backend->dump;
169 }
170 
171 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
172 {
173     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
174 
175     if (!memory_region_size(&backend->mr)) {
176         backend->dump = value;
177         return;
178     }
179 
180     if (value != backend->dump) {
181         void *ptr = memory_region_get_ram_ptr(&backend->mr);
182         uint64_t sz = memory_region_size(&backend->mr);
183 
184         qemu_madvise(ptr, sz,
185                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
186         backend->dump = value;
187     }
188 }
189 
190 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
191 {
192     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
193 
194     return backend->prealloc || backend->force_prealloc;
195 }
196 
197 static void host_memory_backend_set_prealloc(Object *obj, bool value,
198                                              Error **errp)
199 {
200     Error *local_err = NULL;
201     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
202 
203     if (backend->force_prealloc) {
204         if (value) {
205             error_setg(errp,
206                        "remove -mem-prealloc to use the prealloc property");
207             return;
208         }
209     }
210 
211     if (!memory_region_size(&backend->mr)) {
212         backend->prealloc = value;
213         return;
214     }
215 
216     if (value && !backend->prealloc) {
217         int fd = memory_region_get_fd(&backend->mr);
218         void *ptr = memory_region_get_ram_ptr(&backend->mr);
219         uint64_t sz = memory_region_size(&backend->mr);
220 
221         os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
222         if (local_err) {
223             error_propagate(errp, local_err);
224             return;
225         }
226         backend->prealloc = true;
227     }
228 }
229 
230 static void host_memory_backend_init(Object *obj)
231 {
232     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
233     MachineState *machine = MACHINE(qdev_get_machine());
234 
235     backend->merge = machine_mem_merge(machine);
236     backend->dump = machine_dump_guest_core(machine);
237     backend->prealloc = mem_prealloc;
238 }
239 
240 MemoryRegion *
241 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
242 {
243     return memory_region_size(&backend->mr) ? &backend->mr : NULL;
244 }
245 
246 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
247 {
248     backend->is_mapped = mapped;
249 }
250 
251 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
252 {
253     return backend->is_mapped;
254 }
255 
256 static void
257 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
258 {
259     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
260     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
261     Error *local_err = NULL;
262     void *ptr;
263     uint64_t sz;
264 
265     if (bc->alloc) {
266         bc->alloc(backend, &local_err);
267         if (local_err) {
268             goto out;
269         }
270 
271         ptr = memory_region_get_ram_ptr(&backend->mr);
272         sz = memory_region_size(&backend->mr);
273 
274         if (backend->merge) {
275             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
276         }
277         if (!backend->dump) {
278             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
279         }
280 #ifdef CONFIG_NUMA
281         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
282         /* lastbit == MAX_NODES means maxnode = 0 */
283         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
284         /* ensure policy won't be ignored in case memory is preallocated
285          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
286          * this doesn't catch hugepage case. */
287         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
288 
289         /* check for invalid host-nodes and policies and give more verbose
290          * error messages than mbind(). */
291         if (maxnode && backend->policy == MPOL_DEFAULT) {
292             error_setg(errp, "host-nodes must be empty for policy default,"
293                        " or you should explicitly specify a policy other"
294                        " than default");
295             return;
296         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
297             error_setg(errp, "host-nodes must be set for policy %s",
298                        HostMemPolicy_lookup[backend->policy]);
299             return;
300         }
301 
302         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
303          * as argument to mbind() due to an old Linux bug (feature?) which
304          * cuts off the last specified node. This means backend->host_nodes
305          * must have MAX_NODES+1 bits available.
306          */
307         assert(sizeof(backend->host_nodes) >=
308                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
309         assert(maxnode <= MAX_NODES);
310         if (mbind(ptr, sz, backend->policy,
311                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
312             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
313                 error_setg_errno(errp, errno,
314                                  "cannot bind memory to host NUMA nodes");
315                 return;
316             }
317         }
318 #endif
319         /* Preallocate memory after the NUMA policy has been instantiated.
320          * This is necessary to guarantee memory is allocated with
321          * specified NUMA policy in place.
322          */
323         if (backend->prealloc) {
324             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
325                             smp_cpus, &local_err);
326             if (local_err) {
327                 goto out;
328             }
329         }
330     }
331 out:
332     error_propagate(errp, local_err);
333 }
334 
335 static bool
336 host_memory_backend_can_be_deleted(UserCreatable *uc, Error **errp)
337 {
338     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
339         return false;
340     } else {
341         return true;
342     }
343 }
344 
345 static char *get_id(Object *o, Error **errp)
346 {
347     HostMemoryBackend *backend = MEMORY_BACKEND(o);
348 
349     return g_strdup(backend->id);
350 }
351 
352 static void set_id(Object *o, const char *str, Error **errp)
353 {
354     HostMemoryBackend *backend = MEMORY_BACKEND(o);
355 
356     if (backend->id) {
357         error_setg(errp, "cannot change property value");
358         return;
359     }
360     backend->id = g_strdup(str);
361 }
362 
363 static void
364 host_memory_backend_class_init(ObjectClass *oc, void *data)
365 {
366     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
367 
368     ucc->complete = host_memory_backend_memory_complete;
369     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
370 
371     object_class_property_add_bool(oc, "merge",
372         host_memory_backend_get_merge,
373         host_memory_backend_set_merge, &error_abort);
374     object_class_property_add_bool(oc, "dump",
375         host_memory_backend_get_dump,
376         host_memory_backend_set_dump, &error_abort);
377     object_class_property_add_bool(oc, "prealloc",
378         host_memory_backend_get_prealloc,
379         host_memory_backend_set_prealloc, &error_abort);
380     object_class_property_add(oc, "size", "int",
381         host_memory_backend_get_size,
382         host_memory_backend_set_size,
383         NULL, NULL, &error_abort);
384     object_class_property_add(oc, "host-nodes", "int",
385         host_memory_backend_get_host_nodes,
386         host_memory_backend_set_host_nodes,
387         NULL, NULL, &error_abort);
388     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
389         HostMemPolicy_lookup,
390         host_memory_backend_get_policy,
391         host_memory_backend_set_policy, &error_abort);
392     object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);
393 }
394 
395 static void host_memory_backend_finalize(Object *o)
396 {
397     HostMemoryBackend *backend = MEMORY_BACKEND(o);
398     g_free(backend->id);
399 }
400 
401 static const TypeInfo host_memory_backend_info = {
402     .name = TYPE_MEMORY_BACKEND,
403     .parent = TYPE_OBJECT,
404     .abstract = true,
405     .class_size = sizeof(HostMemoryBackendClass),
406     .class_init = host_memory_backend_class_init,
407     .instance_size = sizeof(HostMemoryBackend),
408     .instance_init = host_memory_backend_init,
409     .instance_finalize = host_memory_backend_finalize,
410     .interfaces = (InterfaceInfo[]) {
411         { TYPE_USER_CREATABLE },
412         { }
413     }
414 };
415 
416 static void register_types(void)
417 {
418     type_register_static(&host_memory_backend_info);
419 }
420 
421 type_init(register_types);
422