qemu/backends/hostmem-file.c
Paolo Bonzini dbcb898118 hostmem: add property to map memory with MAP_SHARED
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>
2014-06-19 18:44:20 +03:00

135 lines
3.5 KiB
C

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