xref: /openbmc/qemu/backends/hostmem.c (revision 795c40b8) 
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 (host_memory_backend_mr_inited(backend)) {
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 (!host_memory_backend_mr_inited(backend)) {
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 (!host_memory_backend_mr_inited(backend)) {
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 (!host_memory_backend_mr_inited(backend)) {
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 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
241 {
242     /*
243      * NOTE: We forbid zero-length memory backend, so here zero means
244      * "we haven't inited the backend memory region yet".
245      */
246     return memory_region_size(&backend->mr) != 0;
247 }
248 
249 MemoryRegion *
250 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
251 {
252     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
253 }
254 
255 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
256 {
257     backend->is_mapped = mapped;
258 }
259 
260 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
261 {
262     return backend->is_mapped;
263 }
264 
265 static void
266 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
267 {
268     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
269     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
270     Error *local_err = NULL;
271     void *ptr;
272     uint64_t sz;
273 
274     if (bc->alloc) {
275         bc->alloc(backend, &local_err);
276         if (local_err) {
277             goto out;
278         }
279 
280         ptr = memory_region_get_ram_ptr(&backend->mr);
281         sz = memory_region_size(&backend->mr);
282 
283         if (backend->merge) {
284             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
285         }
286         if (!backend->dump) {
287             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
288         }
289 #ifdef CONFIG_NUMA
290         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
291         /* lastbit == MAX_NODES means maxnode = 0 */
292         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
293         /* ensure policy won't be ignored in case memory is preallocated
294          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
295          * this doesn't catch hugepage case. */
296         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
297 
298         /* check for invalid host-nodes and policies and give more verbose
299          * error messages than mbind(). */
300         if (maxnode && backend->policy == MPOL_DEFAULT) {
301             error_setg(errp, "host-nodes must be empty for policy default,"
302                        " or you should explicitly specify a policy other"
303                        " than default");
304             return;
305         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
306             error_setg(errp, "host-nodes must be set for policy %s",
307                        HostMemPolicy_lookup[backend->policy]);
308             return;
309         }
310 
311         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
312          * as argument to mbind() due to an old Linux bug (feature?) which
313          * cuts off the last specified node. This means backend->host_nodes
314          * must have MAX_NODES+1 bits available.
315          */
316         assert(sizeof(backend->host_nodes) >=
317                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
318         assert(maxnode <= MAX_NODES);
319         if (mbind(ptr, sz, backend->policy,
320                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
321             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
322                 error_setg_errno(errp, errno,
323                                  "cannot bind memory to host NUMA nodes");
324                 return;
325             }
326         }
327 #endif
328         /* Preallocate memory after the NUMA policy has been instantiated.
329          * This is necessary to guarantee memory is allocated with
330          * specified NUMA policy in place.
331          */
332         if (backend->prealloc) {
333             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
334                             smp_cpus, &local_err);
335             if (local_err) {
336                 goto out;
337             }
338         }
339     }
340 out:
341     error_propagate(errp, local_err);
342 }
343 
344 static bool
345 host_memory_backend_can_be_deleted(UserCreatable *uc, Error **errp)
346 {
347     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
348         return false;
349     } else {
350         return true;
351     }
352 }
353 
354 static char *get_id(Object *o, Error **errp)
355 {
356     HostMemoryBackend *backend = MEMORY_BACKEND(o);
357 
358     return g_strdup(backend->id);
359 }
360 
361 static void set_id(Object *o, const char *str, Error **errp)
362 {
363     HostMemoryBackend *backend = MEMORY_BACKEND(o);
364 
365     if (backend->id) {
366         error_setg(errp, "cannot change property value");
367         return;
368     }
369     backend->id = g_strdup(str);
370 }
371 
372 static void
373 host_memory_backend_class_init(ObjectClass *oc, void *data)
374 {
375     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
376 
377     ucc->complete = host_memory_backend_memory_complete;
378     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
379 
380     object_class_property_add_bool(oc, "merge",
381         host_memory_backend_get_merge,
382         host_memory_backend_set_merge, &error_abort);
383     object_class_property_add_bool(oc, "dump",
384         host_memory_backend_get_dump,
385         host_memory_backend_set_dump, &error_abort);
386     object_class_property_add_bool(oc, "prealloc",
387         host_memory_backend_get_prealloc,
388         host_memory_backend_set_prealloc, &error_abort);
389     object_class_property_add(oc, "size", "int",
390         host_memory_backend_get_size,
391         host_memory_backend_set_size,
392         NULL, NULL, &error_abort);
393     object_class_property_add(oc, "host-nodes", "int",
394         host_memory_backend_get_host_nodes,
395         host_memory_backend_set_host_nodes,
396         NULL, NULL, &error_abort);
397     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
398         HostMemPolicy_lookup,
399         host_memory_backend_get_policy,
400         host_memory_backend_set_policy, &error_abort);
401     object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);
402 }
403 
404 static void host_memory_backend_finalize(Object *o)
405 {
406     HostMemoryBackend *backend = MEMORY_BACKEND(o);
407     g_free(backend->id);
408 }
409 
410 static const TypeInfo host_memory_backend_info = {
411     .name = TYPE_MEMORY_BACKEND,
412     .parent = TYPE_OBJECT,
413     .abstract = true,
414     .class_size = sizeof(HostMemoryBackendClass),
415     .class_init = host_memory_backend_class_init,
416     .instance_size = sizeof(HostMemoryBackend),
417     .instance_init = host_memory_backend_init,
418     .instance_finalize = host_memory_backend_finalize,
419     .interfaces = (InterfaceInfo[]) {
420         { TYPE_USER_CREATABLE },
421         { }
422     }
423 };
424 
425 static void register_types(void)
426 {
427     type_register_static(&host_memory_backend_info);
428 }
429 
430 type_init(register_types);
431