qemu/hw/s390x/tod.c
David Hildenbrand 7de3b1cdc6 s390x/tcg: properly implement the TOD
Right now, each CPU has its own TOD. Especially, the TOD will differ
based on creation time of a CPU - e.g. when hotplugging a CPU the times
will differ quite a lot, resulting in stall warnings in the guest.

Let's use a single TOD by implementing our new TOD device. Prepare it
for TOD-clock epoch extension.

Most importantly, whenever we set the TOD, we have to update the CKC
timer.

Introduce "tcg_s390x.h" just like "kvm_s390x.h" for tcg specific
function declarations that should not go into cpu.h.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180627134410.4901-6-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2018-07-02 10:37:38 +02:00

131 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 "sysemu/kvm.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, NULL);
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(NULL, "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);