qemu/backends/hostmem-file.c
Michal Privoznik def835f0da hostmem: Don't report pmem attribute if unsupported
When management applications (like Libvirt) want to check whether
memory-backend-file.pmem is supported they can list object
properties using 'qom-list-properties'. However, 'pmem' is
declared always (and thus reported always) and only at runtime
QEMU errors out if it was built without libpmem (and thus can not
guarantee write persistence). This is suboptimal since we have
ability to declare attributes at compile time.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1915216
Message-Id: <dfcc5dc7e2efc0283bc38e3036da2c0323621cdb.1611647111.git.mprivozn@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2021-02-18 18:34:47 -05:00

229 lines
6.4 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/error-report.h"
#include "qemu/module.h"
#include "sysemu/hostmem.h"
#include "sysemu/sysemu.h"
#include "qom/object_interfaces.h"
#include "qom/object.h"
OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)
struct HostMemoryBackendFile {
HostMemoryBackend parent_obj;
char *mem_path;
uint64_t align;
bool discard_data;
bool is_pmem;
bool readonly;
};
static void
file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
{
#ifndef CONFIG_POSIX
error_setg(errp, "backend '%s' not supported on this host",
object_get_typename(OBJECT(backend)));
#else
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
gchar *name;
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;
}
name = host_memory_backend_get_name(backend);
memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
name,
backend->size, fb->align,
(backend->share ? RAM_SHARED : 0) |
(fb->is_pmem ? RAM_PMEM : 0),
fb->mem_path, fb->readonly, errp);
g_free(name);
#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 'mem-path' of %s",
object_get_typename(o));
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);
uint64_t val;
if (host_memory_backend_mr_inited(backend)) {
error_setg(errp, "cannot change property '%s' of %s", name,
object_get_typename(o));
return;
}
if (!visit_type_size(v, name, &val, errp)) {
return;
}
fb->align = val;
}
#ifdef CONFIG_LIBPMEM
static bool file_memory_backend_get_pmem(Object *o, Error **errp)
{
return MEMORY_BACKEND_FILE(o)->is_pmem;
}
static void file_memory_backend_set_pmem(Object *o, bool value, 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 'pmem' of %s.",
object_get_typename(o));
return;
}
fb->is_pmem = value;
}
#endif /* CONFIG_LIBPMEM */
static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
{
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
return fb->readonly;
}
static void file_memory_backend_set_readonly(Object *obj, bool value,
Error **errp)
{
HostMemoryBackend *backend = MEMORY_BACKEND(obj);
HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
if (host_memory_backend_mr_inited(backend)) {
error_setg(errp, "cannot change property 'readonly' of %s.",
object_get_typename(obj));
return;
}
fb->readonly = value;
}
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);
object_class_property_add_str(oc, "mem-path",
get_mem_path, set_mem_path);
object_class_property_add(oc, "align", "int",
file_memory_backend_get_align,
file_memory_backend_set_align,
NULL, NULL);
#ifdef CONFIG_LIBPMEM
object_class_property_add_bool(oc, "pmem",
file_memory_backend_get_pmem, file_memory_backend_set_pmem);
#endif
object_class_property_add_bool(oc, "readonly",
file_memory_backend_get_readonly,
file_memory_backend_set_readonly);
}
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);