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 #include "qemu/osdep.h" 13 #include "qapi/error.h" 14 #include "qemu-common.h" 15 #include "qemu/error-report.h" 16 #include "sysemu/hostmem.h" 17 #include "sysemu/sysemu.h" 18 #include "qom/object_interfaces.h" 19 20 /* hostmem-file.c */ 21 /** 22 * @TYPE_MEMORY_BACKEND_FILE: 23 * name of backend that uses mmap on a file descriptor 24 */ 25 #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" 26 27 #define MEMORY_BACKEND_FILE(obj) \ 28 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 29 30 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 31 32 struct HostMemoryBackendFile { 33 HostMemoryBackend parent_obj; 34 35 char *mem_path; 36 uint64_t align; 37 bool discard_data; 38 bool is_pmem; 39 }; 40 41 static void 42 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 43 { 44 #ifndef CONFIG_POSIX 45 error_setg(errp, "backend '%s' not supported on this host", 46 object_get_typename(OBJECT(backend))); 47 #else 48 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 49 gchar *name; 50 51 if (!backend->size) { 52 error_setg(errp, "can't create backend with size 0"); 53 return; 54 } 55 if (!fb->mem_path) { 56 error_setg(errp, "mem-path property not set"); 57 return; 58 } 59 backend->force_prealloc = mem_prealloc; 60 name = host_memory_backend_get_name(backend); 61 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 62 name, 63 backend->size, fb->align, 64 (backend->share ? RAM_SHARED : 0) | 65 (fb->is_pmem ? RAM_PMEM : 0), 66 fb->mem_path, errp); 67 g_free(name); 68 #endif 69 } 70 71 static char *get_mem_path(Object *o, Error **errp) 72 { 73 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 74 75 return g_strdup(fb->mem_path); 76 } 77 78 static void set_mem_path(Object *o, const char *str, Error **errp) 79 { 80 HostMemoryBackend *backend = MEMORY_BACKEND(o); 81 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 82 83 if (host_memory_backend_mr_inited(backend)) { 84 error_setg(errp, "cannot change property 'mem-path' of %s", 85 object_get_typename(o)); 86 return; 87 } 88 g_free(fb->mem_path); 89 fb->mem_path = g_strdup(str); 90 } 91 92 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 93 { 94 return MEMORY_BACKEND_FILE(o)->discard_data; 95 } 96 97 static void file_memory_backend_set_discard_data(Object *o, bool value, 98 Error **errp) 99 { 100 MEMORY_BACKEND_FILE(o)->discard_data = value; 101 } 102 103 static void file_memory_backend_get_align(Object *o, Visitor *v, 104 const char *name, void *opaque, 105 Error **errp) 106 { 107 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 108 uint64_t val = fb->align; 109 110 visit_type_size(v, name, &val, errp); 111 } 112 113 static void file_memory_backend_set_align(Object *o, Visitor *v, 114 const char *name, void *opaque, 115 Error **errp) 116 { 117 HostMemoryBackend *backend = MEMORY_BACKEND(o); 118 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 119 Error *local_err = NULL; 120 uint64_t val; 121 122 if (host_memory_backend_mr_inited(backend)) { 123 error_setg(&local_err, "cannot change property '%s' of %s", 124 name, object_get_typename(o)); 125 goto out; 126 } 127 128 visit_type_size(v, name, &val, &local_err); 129 if (local_err) { 130 goto out; 131 } 132 fb->align = val; 133 134 out: 135 error_propagate(errp, local_err); 136 } 137 138 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 139 { 140 return MEMORY_BACKEND_FILE(o)->is_pmem; 141 } 142 143 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 144 { 145 HostMemoryBackend *backend = MEMORY_BACKEND(o); 146 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 147 148 if (host_memory_backend_mr_inited(backend)) { 149 150 error_setg(errp, "cannot change property 'pmem' of %s.", 151 object_get_typename(o)); 152 return; 153 } 154 155 #ifndef CONFIG_LIBPMEM 156 if (value) { 157 Error *local_err = NULL; 158 159 error_setg(&local_err, 160 "Lack of libpmem support while setting the 'pmem=on'" 161 " of %s. We can't ensure data persistence.", 162 object_get_typename(o)); 163 error_propagate(errp, local_err); 164 return; 165 } 166 #endif 167 168 fb->is_pmem = value; 169 } 170 171 static void file_backend_unparent(Object *obj) 172 { 173 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 174 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 175 176 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 177 void *ptr = memory_region_get_ram_ptr(&backend->mr); 178 uint64_t sz = memory_region_size(&backend->mr); 179 180 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 181 } 182 } 183 184 static void 185 file_backend_class_init(ObjectClass *oc, void *data) 186 { 187 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 188 189 bc->alloc = file_backend_memory_alloc; 190 oc->unparent = file_backend_unparent; 191 192 object_class_property_add_bool(oc, "discard-data", 193 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 194 &error_abort); 195 object_class_property_add_str(oc, "mem-path", 196 get_mem_path, set_mem_path, 197 &error_abort); 198 object_class_property_add(oc, "align", "int", 199 file_memory_backend_get_align, 200 file_memory_backend_set_align, 201 NULL, NULL, &error_abort); 202 object_class_property_add_bool(oc, "pmem", 203 file_memory_backend_get_pmem, file_memory_backend_set_pmem, 204 &error_abort); 205 } 206 207 static void file_backend_instance_finalize(Object *o) 208 { 209 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 210 211 g_free(fb->mem_path); 212 } 213 214 static const TypeInfo file_backend_info = { 215 .name = TYPE_MEMORY_BACKEND_FILE, 216 .parent = TYPE_MEMORY_BACKEND, 217 .class_init = file_backend_class_init, 218 .instance_finalize = file_backend_instance_finalize, 219 .instance_size = sizeof(HostMemoryBackendFile), 220 }; 221 222 static void register_types(void) 223 { 224 type_register_static(&file_backend_info); 225 } 226 227 type_init(register_types); 228