blob: 9588b90f2b9cb48b5d7dc675346933bf52472c74 [file] [log] [blame]
/*
* TOD (Time Of Day) clock - KVM implementation
*
* 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 "qapi/error.h"
#include "qemu/module.h"
#include "sysemu/runstate.h"
#include "hw/s390x/tod.h"
#include "target/s390x/kvm/pv.h"
#include "kvm/kvm_s390x.h"
static void kvm_s390_get_tod_raw(S390TOD *tod, Error **errp)
{
int r;
r = kvm_s390_get_clock_ext(&tod->high, &tod->low);
if (r == -ENXIO) {
r = kvm_s390_get_clock(&tod->high, &tod->low);
}
if (r) {
error_setg(errp, "Unable to get KVM guest TOD clock: %s",
strerror(-r));
}
}
static void kvm_s390_tod_get(const S390TODState *td, S390TOD *tod, Error **errp)
{
if (td->stopped) {
*tod = td->base;
return;
}
kvm_s390_get_tod_raw(tod, errp);
}
static void kvm_s390_set_tod_raw(const S390TOD *tod, Error **errp)
{
int r;
r = kvm_s390_set_clock_ext(tod->high, tod->low);
if (r == -ENXIO) {
r = kvm_s390_set_clock(tod->high, tod->low);
}
if (r) {
error_setg(errp, "Unable to set KVM guest TOD clock: %s",
strerror(-r));
}
}
static void kvm_s390_tod_set(S390TODState *td, const S390TOD *tod, Error **errp)
{
Error *local_err = NULL;
/*
* Somebody (e.g. migration) set the TOD. We'll store it into KVM to
* properly detect errors now but take a look at the runstate to decide
* whether really to keep the tod running. E.g. during migration, this
* is the point where we want to stop the initially running TOD to fire
* it back up when actually starting the migrated guest.
*/
kvm_s390_set_tod_raw(tod, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
if (runstate_is_running()) {
td->stopped = false;
} else {
td->stopped = true;
td->base = *tod;
}
}
static void kvm_s390_tod_vm_state_change(void *opaque, bool running,
RunState state)
{
S390TODState *td = opaque;
Error *local_err = NULL;
/*
* Under PV, the clock is under ultravisor control, hence we cannot restore
* it on resume.
*/
if (s390_is_pv()) {
return;
}
if (running && td->stopped) {
/* Set the old TOD when running the VM - start the TOD clock. */
kvm_s390_set_tod_raw(&td->base, &local_err);
if (local_err) {
warn_report_err(local_err);
}
/* Treat errors like the TOD was running all the time. */
td->stopped = false;
} else if (!running && !td->stopped) {
/* Store the TOD when stopping the VM - stop the TOD clock. */
kvm_s390_get_tod_raw(&td->base, &local_err);
if (local_err) {
/* Keep the TOD running in case we could not back it up. */
warn_report_err(local_err);
} else {
td->stopped = true;
}
}
}
static void kvm_s390_tod_realize(DeviceState *dev, Error **errp)
{
S390TODState *td = S390_TOD(dev);
S390TODClass *tdc = S390_TOD_GET_CLASS(td);
Error *local_err = NULL;
tdc->parent_realize(dev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
/*
* We need to know when the VM gets started/stopped to start/stop the TOD.
* As we can never have more than one TOD instance (and that will never be
* removed), registering here and never unregistering is good enough.
*/
qemu_add_vm_change_state_handler(kvm_s390_tod_vm_state_change, td);
}
static void kvm_s390_tod_class_init(ObjectClass *oc, void *data)
{
S390TODClass *tdc = S390_TOD_CLASS(oc);
device_class_set_parent_realize(DEVICE_CLASS(oc), kvm_s390_tod_realize,
&tdc->parent_realize);
tdc->get = kvm_s390_tod_get;
tdc->set = kvm_s390_tod_set;
}
static void kvm_s390_tod_init(Object *obj)
{
S390TODState *td = S390_TOD(obj);
/*
* The TOD is initially running (value stored in KVM). Avoid needless
* loading/storing of the TOD when starting a simple VM, so let it
* run although the (never started) VM is stopped. For migration, we
* will properly set the TOD later.
*/
td->stopped = false;
}
static const TypeInfo kvm_s390_tod_info = {
.name = TYPE_KVM_S390_TOD,
.parent = TYPE_S390_TOD,
.instance_size = sizeof(S390TODState),
.instance_init = kvm_s390_tod_init,
.class_init = kvm_s390_tod_class_init,
.class_size = sizeof(S390TODClass),
};
static void register_types(void)
{
type_register_static(&kvm_s390_tod_info);
}
type_init(register_types);