qemu/backends/hostmem-file.c

187 lines
5.1 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/osdep.h"
#include "qapi/error.h"
#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 discard_data;
char *mem_path;
uint64_t align;
};
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 (!host_memory_backend_mr_inited(backend)) {
gchar *path;
backend->force_prealloc = mem_prealloc;
path = object_get_canonical_path(OBJECT(backend));
memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
path,
backend->size, fb->align, backend->share,
fb->mem_path, errp);
g_free(path);
}
#endif
}
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 (host_memory_backend_mr_inited(backend)) {
error_setg(errp, "cannot change property value");
return;
}
g_free(fb->mem_path);
fb->mem_path = g_strdup(str);
}
static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
{
return MEMORY_BACKEND_FILE(o)->discard_data;
}
static void file_memory_backend_set_discard_data(Object *o, bool value,
Error **errp)
{
MEMORY_BACKEND_FILE(o)->discard_data = value;
}
static void file_memory_backend_get_align(Object *o, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
uint64_t val = fb->align;
visit_type_size(v, name, &val, errp);
}
static void file_memory_backend_set_align(Object *o, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
HostMemoryBackend *backend = MEMORY_BACKEND(o);
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
Error *local_err = NULL;
uint64_t val;
if (host_memory_backend_mr_inited(backend)) {
error_setg(&local_err, "cannot change property value");
goto out;
}
visit_type_size(v, name, &val, &local_err);
if (local_err) {
goto out;
}
fb->align = val;
out:
error_propagate(errp, local_err);
}
static void file_backend_unparent(Object *obj)
{
HostMemoryBackend *backend = MEMORY_BACKEND(obj);
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
void *ptr = memory_region_get_ram_ptr(&backend->mr);
uint64_t sz = memory_region_size(&backend->mr);
qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
}
}
static void
file_backend_class_init(ObjectClass *oc, void *data)
{
HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
bc->alloc = file_backend_memory_alloc;
oc->unparent = file_backend_unparent;
object_class_property_add_bool(oc, "discard-data",
file_memory_backend_get_discard_data, file_memory_backend_set_discard_data,
&error_abort);
object_class_property_add_str(oc, "mem-path",
get_mem_path, set_mem_path,
&error_abort);
object_class_property_add(oc, "align", "int",
file_memory_backend_get_align,
file_memory_backend_set_align,
NULL, NULL, &error_abort);
}
static void file_backend_instance_finalize(Object *o)
{
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
g_free(fb->mem_path);
}
static const TypeInfo file_backend_info = {
.name = TYPE_MEMORY_BACKEND_FILE,
.parent = TYPE_MEMORY_BACKEND,
.class_init = file_backend_class_init,
.instance_finalize = file_backend_instance_finalize,
.instance_size = sizeof(HostMemoryBackendFile),
};
static void register_types(void)
{
type_register_static(&file_backend_info);
}
type_init(register_types);