qemu/hw/s390x/tod.c
Markus Armbruster d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00

133 lines
3.1 KiB
C

/*
* TOD (Time Of Day) clock
*
* Copyright 2018 Red Hat, Inc.
* Author(s): David Hildenbrand <david@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 "hw/s390x/tod.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "sysemu/kvm.h"
#include "migration/qemu-file-types.h"
#include "migration/register.h"
void s390_init_tod(void)
{
Object *obj;
if (kvm_enabled()) {
obj = object_new(TYPE_KVM_S390_TOD);
} else {
obj = object_new(TYPE_QEMU_S390_TOD);
}
object_property_add_child(qdev_get_machine(), TYPE_S390_TOD, obj);
object_unref(obj);
qdev_init_nofail(DEVICE(obj));
}
S390TODState *s390_get_todstate(void)
{
static S390TODState *ts;
if (!ts) {
ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
}
return ts;
}
#define S390_TOD_CLOCK_VALUE_MISSING 0x00
#define S390_TOD_CLOCK_VALUE_PRESENT 0x01
static void s390_tod_save(QEMUFile *f, void *opaque)
{
S390TODState *td = opaque;
S390TODClass *tdc = S390_TOD_GET_CLASS(td);
Error *err = NULL;
S390TOD tod;
tdc->get(td, &tod, &err);
if (err) {
warn_report_err(err);
error_printf("Guest clock will not be migrated "
"which could cause the guest to hang.");
qemu_put_byte(f, S390_TOD_CLOCK_VALUE_MISSING);
return;
}
qemu_put_byte(f, S390_TOD_CLOCK_VALUE_PRESENT);
qemu_put_byte(f, tod.high);
qemu_put_be64(f, tod.low);
}
static int s390_tod_load(QEMUFile *f, void *opaque, int version_id)
{
S390TODState *td = opaque;
S390TODClass *tdc = S390_TOD_GET_CLASS(td);
Error *err = NULL;
S390TOD tod;
if (qemu_get_byte(f) == S390_TOD_CLOCK_VALUE_MISSING) {
warn_report("Guest clock was not migrated. This could "
"cause the guest to hang.");
return 0;
}
tod.high = qemu_get_byte(f);
tod.low = qemu_get_be64(f);
tdc->set(td, &tod, &err);
if (err) {
error_report_err(err);
return -1;
}
return 0;
}
static SaveVMHandlers savevm_tod = {
.save_state = s390_tod_save,
.load_state = s390_tod_load,
};
static void s390_tod_realize(DeviceState *dev, Error **errp)
{
S390TODState *td = S390_TOD(dev);
/* Legacy migration interface */
register_savevm_live("todclock", 0, 1, &savevm_tod, td);
}
static void s390_tod_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
dc->desc = "TOD (Time Of Day) Clock";
dc->realize = s390_tod_realize;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
/* We only have one TOD clock in the system attached to the machine */
dc->user_creatable = false;
}
static TypeInfo s390_tod_info = {
.name = TYPE_S390_TOD,
.parent = TYPE_DEVICE,
.instance_size = sizeof(S390TODState),
.class_init = s390_tod_class_init,
.class_size = sizeof(S390TODClass),
.abstract = true,
};
static void register_types(void)
{
type_register_static(&s390_tod_info);
}
type_init(register_types);