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-common.h" 13 #include "sysemu/hostmem.h" 14 #include "sysemu/sysemu.h" 15 #include "qom/object_interfaces.h" 16 17 /* hostmem-file.c */ 18 /** 19 * @TYPE_MEMORY_BACKEND_FILE: 20 * name of backend that uses mmap on a file descriptor 21 */ 22 #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" 23 24 #define MEMORY_BACKEND_FILE(obj) \ 25 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 26 27 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 28 29 struct HostMemoryBackendFile { 30 HostMemoryBackend parent_obj; 31 32 bool share; 33 char *mem_path; 34 }; 35 36 static void 37 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 38 { 39 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 40 41 if (!backend->size) { 42 error_setg(errp, "can't create backend with size 0"); 43 return; 44 } 45 if (!fb->mem_path) { 46 error_setg(errp, "mem-path property not set"); 47 return; 48 } 49 #ifndef CONFIG_LINUX 50 error_setg(errp, "-mem-path not supported on this host"); 51 #else 52 if (!memory_region_size(&backend->mr)) { 53 backend->force_prealloc = mem_prealloc; 54 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 55 object_get_canonical_path(OBJECT(backend)), 56 backend->size, fb->share, 57 fb->mem_path, errp); 58 } 59 #endif 60 } 61 62 static void 63 file_backend_class_init(ObjectClass *oc, void *data) 64 { 65 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 66 67 bc->alloc = file_backend_memory_alloc; 68 } 69 70 static char *get_mem_path(Object *o, Error **errp) 71 { 72 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 73 74 return g_strdup(fb->mem_path); 75 } 76 77 static void set_mem_path(Object *o, const char *str, Error **errp) 78 { 79 HostMemoryBackend *backend = MEMORY_BACKEND(o); 80 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 81 82 if (memory_region_size(&backend->mr)) { 83 error_setg(errp, "cannot change property value"); 84 return; 85 } 86 g_free(fb->mem_path); 87 fb->mem_path = g_strdup(str); 88 } 89 90 static bool file_memory_backend_get_share(Object *o, Error **errp) 91 { 92 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 93 94 return fb->share; 95 } 96 97 static void file_memory_backend_set_share(Object *o, bool value, Error **errp) 98 { 99 HostMemoryBackend *backend = MEMORY_BACKEND(o); 100 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 101 102 if (memory_region_size(&backend->mr)) { 103 error_setg(errp, "cannot change property value"); 104 return; 105 } 106 fb->share = value; 107 } 108 109 static void 110 file_backend_instance_init(Object *o) 111 { 112 object_property_add_bool(o, "share", 113 file_memory_backend_get_share, 114 file_memory_backend_set_share, NULL); 115 object_property_add_str(o, "mem-path", get_mem_path, 116 set_mem_path, NULL); 117 } 118 119 static const TypeInfo file_backend_info = { 120 .name = TYPE_MEMORY_BACKEND_FILE, 121 .parent = TYPE_MEMORY_BACKEND, 122 .class_init = file_backend_class_init, 123 .instance_init = file_backend_instance_init, 124 .instance_size = sizeof(HostMemoryBackendFile), 125 }; 126 127 static void register_types(void) 128 { 129 type_register_static(&file_backend_info); 130 } 131 132 type_init(register_types); 133