1 /* 2 * QEMU Host Memory Backend for hugetlbfs 3 * 4 * Copyright (C) 2013-2014 Red Hat Inc 5 * 6 * Authors: 7 * Paolo Bonzini <pbonzini@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 "qapi/error.h" 15 #include "qemu/error-report.h" 16 #include "qemu/module.h" 17 #include "sysemu/hostmem.h" 18 #include "sysemu/sysemu.h" 19 #include "qom/object_interfaces.h" 20 21 #define MEMORY_BACKEND_FILE(obj) \ 22 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 23 24 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 25 26 struct HostMemoryBackendFile { 27 HostMemoryBackend parent_obj; 28 29 char *mem_path; 30 uint64_t align; 31 bool discard_data; 32 bool is_pmem; 33 }; 34 35 static void 36 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 37 { 38 #ifndef CONFIG_POSIX 39 error_setg(errp, "backend '%s' not supported on this host", 40 object_get_typename(OBJECT(backend))); 41 #else 42 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 43 gchar *name; 44 45 if (!backend->size) { 46 error_setg(errp, "can't create backend with size 0"); 47 return; 48 } 49 if (!fb->mem_path) { 50 error_setg(errp, "mem-path property not set"); 51 return; 52 } 53 54 backend->force_prealloc = mem_prealloc; 55 name = host_memory_backend_get_name(backend); 56 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 57 name, 58 backend->size, fb->align, 59 (backend->share ? RAM_SHARED : 0) | 60 (fb->is_pmem ? RAM_PMEM : 0), 61 fb->mem_path, errp); 62 g_free(name); 63 #endif 64 } 65 66 static char *get_mem_path(Object *o, Error **errp) 67 { 68 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 69 70 return g_strdup(fb->mem_path); 71 } 72 73 static void set_mem_path(Object *o, const char *str, Error **errp) 74 { 75 HostMemoryBackend *backend = MEMORY_BACKEND(o); 76 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 77 78 if (host_memory_backend_mr_inited(backend)) { 79 error_setg(errp, "cannot change property 'mem-path' of %s", 80 object_get_typename(o)); 81 return; 82 } 83 g_free(fb->mem_path); 84 fb->mem_path = g_strdup(str); 85 } 86 87 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 88 { 89 return MEMORY_BACKEND_FILE(o)->discard_data; 90 } 91 92 static void file_memory_backend_set_discard_data(Object *o, bool value, 93 Error **errp) 94 { 95 MEMORY_BACKEND_FILE(o)->discard_data = value; 96 } 97 98 static void file_memory_backend_get_align(Object *o, Visitor *v, 99 const char *name, void *opaque, 100 Error **errp) 101 { 102 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 103 uint64_t val = fb->align; 104 105 visit_type_size(v, name, &val, errp); 106 } 107 108 static void file_memory_backend_set_align(Object *o, Visitor *v, 109 const char *name, void *opaque, 110 Error **errp) 111 { 112 HostMemoryBackend *backend = MEMORY_BACKEND(o); 113 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 114 Error *local_err = NULL; 115 uint64_t val; 116 117 if (host_memory_backend_mr_inited(backend)) { 118 error_setg(&local_err, "cannot change property '%s' of %s", 119 name, object_get_typename(o)); 120 goto out; 121 } 122 123 visit_type_size(v, name, &val, &local_err); 124 if (local_err) { 125 goto out; 126 } 127 fb->align = val; 128 129 out: 130 error_propagate(errp, local_err); 131 } 132 133 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 134 { 135 return MEMORY_BACKEND_FILE(o)->is_pmem; 136 } 137 138 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 139 { 140 HostMemoryBackend *backend = MEMORY_BACKEND(o); 141 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 142 143 if (host_memory_backend_mr_inited(backend)) { 144 145 error_setg(errp, "cannot change property 'pmem' of %s.", 146 object_get_typename(o)); 147 return; 148 } 149 150 #ifndef CONFIG_LIBPMEM 151 if (value) { 152 Error *local_err = NULL; 153 154 error_setg(&local_err, 155 "Lack of libpmem support while setting the 'pmem=on'" 156 " of %s. We can't ensure data persistence.", 157 object_get_typename(o)); 158 error_propagate(errp, local_err); 159 return; 160 } 161 #endif 162 163 fb->is_pmem = value; 164 } 165 166 static void file_backend_unparent(Object *obj) 167 { 168 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 169 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 170 171 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 172 void *ptr = memory_region_get_ram_ptr(&backend->mr); 173 uint64_t sz = memory_region_size(&backend->mr); 174 175 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 176 } 177 } 178 179 static void 180 file_backend_class_init(ObjectClass *oc, void *data) 181 { 182 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 183 184 bc->alloc = file_backend_memory_alloc; 185 oc->unparent = file_backend_unparent; 186 187 object_class_property_add_bool(oc, "discard-data", 188 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 189 &error_abort); 190 object_class_property_add_str(oc, "mem-path", 191 get_mem_path, set_mem_path, 192 &error_abort); 193 object_class_property_add(oc, "align", "int", 194 file_memory_backend_get_align, 195 file_memory_backend_set_align, 196 NULL, NULL, &error_abort); 197 object_class_property_add_bool(oc, "pmem", 198 file_memory_backend_get_pmem, file_memory_backend_set_pmem, 199 &error_abort); 200 } 201 202 static void file_backend_instance_finalize(Object *o) 203 { 204 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 205 206 g_free(fb->mem_path); 207 } 208 209 static const TypeInfo file_backend_info = { 210 .name = TYPE_MEMORY_BACKEND_FILE, 211 .parent = TYPE_MEMORY_BACKEND, 212 .class_init = file_backend_class_init, 213 .instance_finalize = file_backend_instance_finalize, 214 .instance_size = sizeof(HostMemoryBackendFile), 215 }; 216 217 static void register_types(void) 218 { 219 type_register_static(&file_backend_info); 220 } 221 222 type_init(register_types); 223