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 #include "qom/object.h" 21 22 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 23 DECLARE_INSTANCE_CHECKER(HostMemoryBackendFile, MEMORY_BACKEND_FILE, 24 TYPE_MEMORY_BACKEND_FILE) 25 26 27 struct HostMemoryBackendFile { 28 HostMemoryBackend parent_obj; 29 30 char *mem_path; 31 uint64_t align; 32 bool discard_data; 33 bool is_pmem; 34 }; 35 36 static void 37 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 38 { 39 #ifndef CONFIG_POSIX 40 error_setg(errp, "backend '%s' not supported on this host", 41 object_get_typename(OBJECT(backend))); 42 #else 43 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 44 gchar *name; 45 46 if (!backend->size) { 47 error_setg(errp, "can't create backend with size 0"); 48 return; 49 } 50 if (!fb->mem_path) { 51 error_setg(errp, "mem-path property not set"); 52 return; 53 } 54 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 uint64_t val; 115 116 if (host_memory_backend_mr_inited(backend)) { 117 error_setg(errp, "cannot change property '%s' of %s", name, 118 object_get_typename(o)); 119 return; 120 } 121 122 if (!visit_type_size(v, name, &val, errp)) { 123 return; 124 } 125 fb->align = val; 126 } 127 128 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 129 { 130 return MEMORY_BACKEND_FILE(o)->is_pmem; 131 } 132 133 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 134 { 135 HostMemoryBackend *backend = MEMORY_BACKEND(o); 136 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 137 138 if (host_memory_backend_mr_inited(backend)) { 139 error_setg(errp, "cannot change property 'pmem' of %s.", 140 object_get_typename(o)); 141 return; 142 } 143 144 #ifndef CONFIG_LIBPMEM 145 if (value) { 146 error_setg(errp, "Lack of libpmem support while setting the 'pmem=on'" 147 " of %s. We can't ensure data persistence.", 148 object_get_typename(o)); 149 return; 150 } 151 #endif 152 153 fb->is_pmem = value; 154 } 155 156 static void file_backend_unparent(Object *obj) 157 { 158 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 159 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 160 161 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 162 void *ptr = memory_region_get_ram_ptr(&backend->mr); 163 uint64_t sz = memory_region_size(&backend->mr); 164 165 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 166 } 167 } 168 169 static void 170 file_backend_class_init(ObjectClass *oc, void *data) 171 { 172 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 173 174 bc->alloc = file_backend_memory_alloc; 175 oc->unparent = file_backend_unparent; 176 177 object_class_property_add_bool(oc, "discard-data", 178 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data); 179 object_class_property_add_str(oc, "mem-path", 180 get_mem_path, set_mem_path); 181 object_class_property_add(oc, "align", "int", 182 file_memory_backend_get_align, 183 file_memory_backend_set_align, 184 NULL, NULL); 185 object_class_property_add_bool(oc, "pmem", 186 file_memory_backend_get_pmem, file_memory_backend_set_pmem); 187 } 188 189 static void file_backend_instance_finalize(Object *o) 190 { 191 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 192 193 g_free(fb->mem_path); 194 } 195 196 static const TypeInfo file_backend_info = { 197 .name = TYPE_MEMORY_BACKEND_FILE, 198 .parent = TYPE_MEMORY_BACKEND, 199 .class_init = file_backend_class_init, 200 .instance_finalize = file_backend_instance_finalize, 201 .instance_size = sizeof(HostMemoryBackendFile), 202 }; 203 204 static void register_types(void) 205 { 206 type_register_static(&file_backend_info); 207 } 208 209 type_init(register_types); 210