dbcb898118
A new "share" property can be used with the "memory-file" backend to map memory with MAP_SHARED instead of MAP_PRIVATE. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
/*
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* QEMU Host Memory Backend for hugetlbfs
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*
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* Copyright (C) 2013-2014 Red Hat Inc
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*
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* Authors:
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* Paolo Bonzini <pbonzini@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu-common.h"
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#include "sysemu/hostmem.h"
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#include "sysemu/sysemu.h"
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#include "qom/object_interfaces.h"
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/* hostmem-file.c */
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/**
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* @TYPE_MEMORY_BACKEND_FILE:
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* name of backend that uses mmap on a file descriptor
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*/
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#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"
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#define MEMORY_BACKEND_FILE(obj) \
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OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE)
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typedef struct HostMemoryBackendFile HostMemoryBackendFile;
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struct HostMemoryBackendFile {
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HostMemoryBackend parent_obj;
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bool share;
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char *mem_path;
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};
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static void
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file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
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{
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HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
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if (!backend->size) {
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error_setg(errp, "can't create backend with size 0");
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return;
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}
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if (!fb->mem_path) {
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error_setg(errp, "mem_path property not set");
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return;
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}
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#ifndef CONFIG_LINUX
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error_setg(errp, "-mem-path not supported on this host");
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#else
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if (!memory_region_size(&backend->mr)) {
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backend->force_prealloc = mem_prealloc;
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memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
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object_get_canonical_path(OBJECT(backend)),
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backend->size, fb->share,
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fb->mem_path, errp);
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}
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#endif
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}
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static void
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file_backend_class_init(ObjectClass *oc, void *data)
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{
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HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
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bc->alloc = file_backend_memory_alloc;
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}
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static char *get_mem_path(Object *o, Error **errp)
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{
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HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
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return g_strdup(fb->mem_path);
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}
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static void set_mem_path(Object *o, const char *str, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
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if (memory_region_size(&backend->mr)) {
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error_setg(errp, "cannot change property value");
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return;
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}
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if (fb->mem_path) {
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g_free(fb->mem_path);
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}
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fb->mem_path = g_strdup(str);
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}
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static bool file_memory_backend_get_share(Object *o, Error **errp)
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{
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HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
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return fb->share;
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}
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static void file_memory_backend_set_share(Object *o, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
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if (memory_region_size(&backend->mr)) {
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error_setg(errp, "cannot change property value");
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return;
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}
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fb->share = value;
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}
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static void
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file_backend_instance_init(Object *o)
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{
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object_property_add_bool(o, "share",
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file_memory_backend_get_share,
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file_memory_backend_set_share, NULL);
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object_property_add_str(o, "mem-path", get_mem_path,
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set_mem_path, NULL);
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}
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static const TypeInfo file_backend_info = {
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.name = TYPE_MEMORY_BACKEND_FILE,
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.parent = TYPE_MEMORY_BACKEND,
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.class_init = file_backend_class_init,
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.instance_init = file_backend_instance_init,
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.instance_size = sizeof(HostMemoryBackendFile),
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};
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static void register_types(void)
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{
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type_register_static(&file_backend_info);
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}
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type_init(register_types);
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