xref: /qemu/backends/hostmem.c (revision dc03272d) 
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 
13 #include "qemu/osdep.h"
14 #include "sysemu/hostmem.h"
15 #include "hw/boards.h"
16 #include "qapi/error.h"
17 #include "qapi/qapi-builtin-visit.h"
18 #include "qapi/visitor.h"
19 #include "qemu/config-file.h"
20 #include "qom/object_interfaces.h"
21 #include "qemu/mmap-alloc.h"
22 
23 #ifdef CONFIG_NUMA
24 #include <numaif.h>
25 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
26 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
27 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
28 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
29 #endif
30 
31 static void
32 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
33                              void *opaque, Error **errp)
34 {
35     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
36     uint64_t value = backend->size;
37 
38     visit_type_size(v, name, &value, errp);
39 }
40 
41 static void
42 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
43                              void *opaque, Error **errp)
44 {
45     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
46     Error *local_err = NULL;
47     uint64_t value;
48 
49     if (host_memory_backend_mr_inited(backend)) {
50         error_setg(&local_err, "cannot change property value");
51         goto out;
52     }
53 
54     visit_type_size(v, name, &value, &local_err);
55     if (local_err) {
56         goto out;
57     }
58     if (!value) {
59         error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
60                    PRIu64 "'", object_get_typename(obj), name, value);
61         goto out;
62     }
63     backend->size = value;
64 out:
65     error_propagate(errp, local_err);
66 }
67 
68 static void
69 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
70                                    void *opaque, Error **errp)
71 {
72     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
73     uint16List *host_nodes = NULL;
74     uint16List **node = &host_nodes;
75     unsigned long value;
76 
77     value = find_first_bit(backend->host_nodes, MAX_NODES);
78     if (value == MAX_NODES) {
79         return;
80     }
81 
82     *node = g_malloc0(sizeof(**node));
83     (*node)->value = value;
84     node = &(*node)->next;
85 
86     do {
87         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
88         if (value == MAX_NODES) {
89             break;
90         }
91 
92         *node = g_malloc0(sizeof(**node));
93         (*node)->value = value;
94         node = &(*node)->next;
95     } while (true);
96 
97     visit_type_uint16List(v, name, &host_nodes, errp);
98 }
99 
100 static void
101 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
102                                    void *opaque, Error **errp)
103 {
104 #ifdef CONFIG_NUMA
105     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
106     uint16List *l = NULL;
107 
108     visit_type_uint16List(v, name, &l, errp);
109 
110     while (l) {
111         bitmap_set(backend->host_nodes, l->value, 1);
112         l = l->next;
113     }
114 #else
115     error_setg(errp, "NUMA node binding are not supported by this QEMU");
116 #endif
117 }
118 
119 static int
120 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
121 {
122     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
123     return backend->policy;
124 }
125 
126 static void
127 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
128 {
129     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
130     backend->policy = policy;
131 
132 #ifndef CONFIG_NUMA
133     if (policy != HOST_MEM_POLICY_DEFAULT) {
134         error_setg(errp, "NUMA policies are not supported by this QEMU");
135     }
136 #endif
137 }
138 
139 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
140 {
141     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
142 
143     return backend->merge;
144 }
145 
146 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
147 {
148     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
149 
150     if (!host_memory_backend_mr_inited(backend)) {
151         backend->merge = value;
152         return;
153     }
154 
155     if (value != backend->merge) {
156         void *ptr = memory_region_get_ram_ptr(&backend->mr);
157         uint64_t sz = memory_region_size(&backend->mr);
158 
159         qemu_madvise(ptr, sz,
160                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
161         backend->merge = value;
162     }
163 }
164 
165 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
166 {
167     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
168 
169     return backend->dump;
170 }
171 
172 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
173 {
174     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
175 
176     if (!host_memory_backend_mr_inited(backend)) {
177         backend->dump = value;
178         return;
179     }
180 
181     if (value != backend->dump) {
182         void *ptr = memory_region_get_ram_ptr(&backend->mr);
183         uint64_t sz = memory_region_size(&backend->mr);
184 
185         qemu_madvise(ptr, sz,
186                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
187         backend->dump = value;
188     }
189 }
190 
191 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
192 {
193     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
194 
195     return backend->prealloc || backend->force_prealloc;
196 }
197 
198 static void host_memory_backend_set_prealloc(Object *obj, bool value,
199                                              Error **errp)
200 {
201     Error *local_err = NULL;
202     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
203 
204     if (backend->force_prealloc) {
205         if (value) {
206             error_setg(errp,
207                        "remove -mem-prealloc to use the prealloc property");
208             return;
209         }
210     }
211 
212     if (!host_memory_backend_mr_inited(backend)) {
213         backend->prealloc = value;
214         return;
215     }
216 
217     if (value && !backend->prealloc) {
218         int fd = memory_region_get_fd(&backend->mr);
219         void *ptr = memory_region_get_ram_ptr(&backend->mr);
220         uint64_t sz = memory_region_size(&backend->mr);
221 
222         os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
223         if (local_err) {
224             error_propagate(errp, local_err);
225             return;
226         }
227         backend->prealloc = true;
228     }
229 }
230 
231 static void host_memory_backend_init(Object *obj)
232 {
233     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
234     MachineState *machine = MACHINE(qdev_get_machine());
235 
236     backend->merge = machine_mem_merge(machine);
237     backend->dump = machine_dump_guest_core(machine);
238     backend->prealloc = mem_prealloc;
239 }
240 
241 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
242 {
243     /*
244      * NOTE: We forbid zero-length memory backend, so here zero means
245      * "we haven't inited the backend memory region yet".
246      */
247     return memory_region_size(&backend->mr) != 0;
248 }
249 
250 MemoryRegion *
251 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
252 {
253     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
254 }
255 
256 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
257 {
258     backend->is_mapped = mapped;
259 }
260 
261 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
262 {
263     return backend->is_mapped;
264 }
265 
266 #ifdef __linux__
267 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
268 {
269     Object *obj = OBJECT(memdev);
270     char *path = object_property_get_str(obj, "mem-path", NULL);
271     size_t pagesize = qemu_mempath_getpagesize(path);
272 
273     g_free(path);
274     return pagesize;
275 }
276 #else
277 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
278 {
279     return getpagesize();
280 }
281 #endif
282 
283 static void
284 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
285 {
286     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
287     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
288     Error *local_err = NULL;
289     void *ptr;
290     uint64_t sz;
291 
292     if (bc->alloc) {
293         bc->alloc(backend, &local_err);
294         if (local_err) {
295             goto out;
296         }
297 
298         ptr = memory_region_get_ram_ptr(&backend->mr);
299         sz = memory_region_size(&backend->mr);
300 
301         if (backend->merge) {
302             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
303         }
304         if (!backend->dump) {
305             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
306         }
307 #ifdef CONFIG_NUMA
308         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
309         /* lastbit == MAX_NODES means maxnode = 0 */
310         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
311         /* ensure policy won't be ignored in case memory is preallocated
312          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
313          * this doesn't catch hugepage case. */
314         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
315 
316         /* check for invalid host-nodes and policies and give more verbose
317          * error messages than mbind(). */
318         if (maxnode && backend->policy == MPOL_DEFAULT) {
319             error_setg(errp, "host-nodes must be empty for policy default,"
320                        " or you should explicitly specify a policy other"
321                        " than default");
322             return;
323         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
324             error_setg(errp, "host-nodes must be set for policy %s",
325                        HostMemPolicy_str(backend->policy));
326             return;
327         }
328 
329         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
330          * as argument to mbind() due to an old Linux bug (feature?) which
331          * cuts off the last specified node. This means backend->host_nodes
332          * must have MAX_NODES+1 bits available.
333          */
334         assert(sizeof(backend->host_nodes) >=
335                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
336         assert(maxnode <= MAX_NODES);
337         if (mbind(ptr, sz, backend->policy,
338                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
339             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
340                 error_setg_errno(errp, errno,
341                                  "cannot bind memory to host NUMA nodes");
342                 return;
343             }
344         }
345 #endif
346         /* Preallocate memory after the NUMA policy has been instantiated.
347          * This is necessary to guarantee memory is allocated with
348          * specified NUMA policy in place.
349          */
350         if (backend->prealloc) {
351             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
352                             smp_cpus, &local_err);
353             if (local_err) {
354                 goto out;
355             }
356         }
357     }
358 out:
359     error_propagate(errp, local_err);
360 }
361 
362 static bool
363 host_memory_backend_can_be_deleted(UserCreatable *uc)
364 {
365     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
366         return false;
367     } else {
368         return true;
369     }
370 }
371 
372 static bool host_memory_backend_get_share(Object *o, Error **errp)
373 {
374     HostMemoryBackend *backend = MEMORY_BACKEND(o);
375 
376     return backend->share;
377 }
378 
379 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
380 {
381     HostMemoryBackend *backend = MEMORY_BACKEND(o);
382 
383     if (host_memory_backend_mr_inited(backend)) {
384         error_setg(errp, "cannot change property value");
385         return;
386     }
387     backend->share = value;
388 }
389 
390 static void
391 host_memory_backend_class_init(ObjectClass *oc, void *data)
392 {
393     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
394 
395     ucc->complete = host_memory_backend_memory_complete;
396     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
397 
398     object_class_property_add_bool(oc, "merge",
399         host_memory_backend_get_merge,
400         host_memory_backend_set_merge, &error_abort);
401     object_class_property_add_bool(oc, "dump",
402         host_memory_backend_get_dump,
403         host_memory_backend_set_dump, &error_abort);
404     object_class_property_add_bool(oc, "prealloc",
405         host_memory_backend_get_prealloc,
406         host_memory_backend_set_prealloc, &error_abort);
407     object_class_property_add(oc, "size", "int",
408         host_memory_backend_get_size,
409         host_memory_backend_set_size,
410         NULL, NULL, &error_abort);
411     object_class_property_add(oc, "host-nodes", "int",
412         host_memory_backend_get_host_nodes,
413         host_memory_backend_set_host_nodes,
414         NULL, NULL, &error_abort);
415     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
416         &HostMemPolicy_lookup,
417         host_memory_backend_get_policy,
418         host_memory_backend_set_policy, &error_abort);
419     object_class_property_add_bool(oc, "share",
420         host_memory_backend_get_share, host_memory_backend_set_share,
421         &error_abort);
422 }
423 
424 static const TypeInfo host_memory_backend_info = {
425     .name = TYPE_MEMORY_BACKEND,
426     .parent = TYPE_OBJECT,
427     .abstract = true,
428     .class_size = sizeof(HostMemoryBackendClass),
429     .class_init = host_memory_backend_class_init,
430     .instance_size = sizeof(HostMemoryBackend),
431     .instance_init = host_memory_backend_init,
432     .interfaces = (InterfaceInfo[]) {
433         { TYPE_USER_CREATABLE },
434         { }
435     }
436 };
437 
438 static void register_types(void)
439 {
440     type_register_static(&host_memory_backend_info);
441 }
442 
443 type_init(register_types);
444